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Repair of Samsung 55" TV - backlight problem
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Peabody
Jul 21, 2022, 12:01:15 AM7/21/22
to
Friends of mine have a Samsung 55" 4K TV, model UN55HU6840 (about 2014).
They say they can hear audio, but the screen is black. I'd like to take a
shot at fixing it for them since they don't really have the money to buy
a new one. The encouraging thing is that until recently this has been an
intermittent problem that's just gradually gotten worse, and now is
permanent. But I'm encouraged to think it's not burned out LEDs, else it
would never have been intermittent.
I just told you everything I know about repairing TVs, but am generally
experienced in electronics as a hobbyist. Based on some Youtube videos
it seems I should take off the back cover and check all the connections.
Then I would go to the power board and check the voltages on the lines
going to the backlight LEDs, and if low, start checking diodes and
electrolytics, and of course look for bad solder joints.
Does this sound like a reasonable approach? Is there a typical cause of
this symptom?
I've had no luck finding a schematic. Does anyone know where I would
find that?
Well, any guidance would be appreciated.
They say they can hear audio, but the screen is black. I'd like to take a
shot at fixing it for them since they don't really have the money to buy
a new one. The encouraging thing is that until recently this has been an
intermittent problem that's just gradually gotten worse, and now is
permanent. But I'm encouraged to think it's not burned out LEDs, else it
would never have been intermittent.
I just told you everything I know about repairing TVs, but am generally
experienced in electronics as a hobbyist. Based on some Youtube videos
it seems I should take off the back cover and check all the connections.
Then I would go to the power board and check the voltages on the lines
going to the backlight LEDs, and if low, start checking diodes and
electrolytics, and of course look for bad solder joints.
Does this sound like a reasonable approach? Is there a typical cause of
this symptom?
I've had no luck finding a schematic. Does anyone know where I would
find that?
Well, any guidance would be appreciated.
Jeff Liebermann
Jul 21, 2022, 12:45:45 AM7/21/22
to
On Wed, 20 Jul 2022 23:01:11 -0500, Peabody
<waybackNO...@yahoo.com> wrote:
>Friends of mine have a Samsung 55" 4K TV, model UN55HU6840 (about 2014).
>They say they can hear audio, but the screen is black.
Have your friend turn on the TV and pretend that it has video. Make
<waybackNO...@yahoo.com> wrote:
>Friends of mine have a Samsung 55" 4K TV, model UN55HU6840 (about 2014).
>They say they can hear audio, but the screen is black.
sure he can hear the audio that goes with the video. Have him take a
flashlight and illuminate an area where you know there should be a
picture. No movies with dark scenes please. Have him move the
flashlight around and try different angles and room lighting. If he
sees anything that looks like a faint image on the screen, then the TV
has an backlighting problem. That model uses LED edge lighting, so
look for problems in that area. If he doesn't see anything with the
flashlight, then it's a video problem. Your approach is ok, but
without a service manual and a schematic, repairing a PCB might be
problematic. Think about isolating the problem to a particular PCB
and order a used replacement from the cannibals on eBay.
--
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558
Peabody
Jul 21, 2022, 11:10:33 AM7/21/22
to
Jeff Liebermann says...
> Your approach is ok, but without a service manual and a
> schematic, repairing a PCB might be problematic. Think
> about isolating the problem to a particular PCB and
> order a used replacement from the cannibals on eBay.
They've already taken it down and put it in the garage, so
I'll have to do the flashlight test when they bring it to
me. But I have a little more information.
This happened before, about three years ago, and they spent
$250 at a local repair shop, which replaced one of the
boards. But they don't know which board, and don't have the
paperwork that might tell. But they say the symptoms are
the same.
I found a repair video of this exact model:
https://www.youtube.com/watch?v=nhFnoLILlG4
which turned out to be bad electrolytics. I haven't done a
lot of repairs, but so far pretty much all of them have been
bad caps - usually high ESR. Most recently, that's two
Disney coffee mug warmers and the power supply for my Ooma
box. Anyway, what I'm hoping for is either a bad connection,
or a bad solder joint, or some component on the power board
that I can replace. I'm encouraged by the size of the
components on that board - not all tiny 0201 smd, but
through-hole stuff as God intended.
Well, I'm not sure anything will come of this, but I think
it's worth giving it a shot. And working on stuff like this
is my idea of a good time. But I would sure like to find the
schematic
Film at 11.
> Your approach is ok, but without a service manual and a
> schematic, repairing a PCB might be problematic. Think
> about isolating the problem to a particular PCB and
> order a used replacement from the cannibals on eBay.
I'll have to do the flashlight test when they bring it to
me. But I have a little more information.
This happened before, about three years ago, and they spent
$250 at a local repair shop, which replaced one of the
boards. But they don't know which board, and don't have the
paperwork that might tell. But they say the symptoms are
the same.
I found a repair video of this exact model:
https://www.youtube.com/watch?v=nhFnoLILlG4
which turned out to be bad electrolytics. I haven't done a
lot of repairs, but so far pretty much all of them have been
bad caps - usually high ESR. Most recently, that's two
Disney coffee mug warmers and the power supply for my Ooma
box. Anyway, what I'm hoping for is either a bad connection,
or a bad solder joint, or some component on the power board
that I can replace. I'm encouraged by the size of the
components on that board - not all tiny 0201 smd, but
through-hole stuff as God intended.
Well, I'm not sure anything will come of this, but I think
it's worth giving it a shot. And working on stuff like this
is my idea of a good time. But I would sure like to find the
schematic
Film at 11.
Jeff Liebermann
Jul 21, 2022, 12:16:23 PM7/21/22
to
On Thu, 21 Jul 2022 10:10:30 -0500, Peabody
<waybackNO...@yahoo.com> wrote:
>This happened before, about three years ago, and they spent
>$250 at a local repair shop, which replaced one of the
>boards. But they don't know which board, and don't have the
>paperwork that might tell. But they say the symptoms are
>the same.
You might be able to identify which PCB was replaced by inspecting the
<waybackNO...@yahoo.com> wrote:
>This happened before, about three years ago, and they spent
>$250 at a local repair shop, which replaced one of the
>boards. But they don't know which board, and don't have the
>paperwork that might tell. But they say the symptoms are
>the same.
heads on the PCB mounting screws for wear caused by the screwdriver
bit.
I don't know about your local repair shop. The lack of historical
information sounds like they want you to bring the TV in for another
repair instead of fixing it yourself.
In California, repair shops are required to keep records for 3 years.
<https://bhgs.dca.ca.gov/laws/ear_regs.pdf>
9842. One copy shall be given to the customer and one copy shall be
retained by the service dealer for a period of at least three years.
2764. Record Keeping - Customer-related Records
A legible original or legible copy of the following records shall be
retained by the service dealer for a period of at least three years:
invoice, customer claim check, estimate records, and employee records.
If your friend paid sales tax on the parts, the shop has to keep
records for 4 years.
Different states will have different rules and time periods.
ohg...@gmail.com
Jul 21, 2022, 12:17:34 PM7/21/22
to
legg
Jul 21, 2022, 3:35:46 PM7/21/22
to
On Wed, 20 Jul 2022 21:45:35 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:
>UN55HU6840
You might try a manual 'reset to factory', or a USB
re-flash. These procedures don't need an active screen
or remote.
I've yet to run across an audio-ok/blackscreen situation,
so can't advise.
You can take off the back and hunt for obvious problems
like bulging caps or iffy connectors.
To troubleshoot, you'll really need to get a service manual.
This should tell you how to get the back off, without
bending something. It will also offer test points for
measurement.
RL
wrote:
>UN55HU6840
You might try a manual 'reset to factory', or a USB
re-flash. These procedures don't need an active screen
or remote.
I've yet to run across an audio-ok/blackscreen situation,
so can't advise.
You can take off the back and hunt for obvious problems
like bulging caps or iffy connectors.
To troubleshoot, you'll really need to get a service manual.
This should tell you how to get the back off, without
bending something. It will also offer test points for
measurement.
RL
Jeff Liebermann
Jul 21, 2022, 6:04:33 PM7/21/22
to
On Thu, 21 Jul 2022 15:36:36 -0400, legg <le...@nospam.magma.ca> wrote:
>On Wed, 20 Jul 2022 21:45:35 -0700, Jeff Liebermann <je...@cruzio.com>
>wrote:
>
>>UN55HU6840
>
>You might try a manual 'reset to factory', or a USB
>re-flash. These procedures don't need an active screen
>or remote.
I looked at the user manual and searched the internet for such a
>On Wed, 20 Jul 2022 21:45:35 -0700, Jeff Liebermann <je...@cruzio.com>
>wrote:
>
>>UN55HU6840
>
>You might try a manual 'reset to factory', or a USB
>re-flash. These procedures don't need an active screen
>or remote.
procedure. There are two resets. One for resetting the smart hub and
another for resetting everything except the network settings. Both
are access from the setting menu which requires seeing something on
the screen. There are probably instruction for a factory reset
without using the remote or screen, but I couldn't find them.
>I've yet to run across an audio-ok/blackscreen situation,
>so can't advise.
>You can take off the back and hunt for obvious problems
> like bulging caps or iffy connectors.
bulging or leakage. I suggest an ESR tester to be certain.
>To troubleshoot, you'll really need to get a service manual.
>This should tell you how to get the back off, without
>bending something. It will also offer test points for
>measurement.
>
>RL
Peabody
Jul 21, 2022, 9:21:16 PM7/21/22
to
ohg...@gmail.com says...
> The HU series *does* have intermittent issues with LEDs,
> either from individual LEDs or the interconnects on the
> strips. Sometimes you can change just the bad LEDs or
> hardwire the interconnects if there is a voltage drop
> across them, but the best option is to order the
> complete set of strips from someone like ShopJimmy.
Having no experience with these TVs, I don't know how the
LEDs are connected to power lines, or how the lines are
interconnected. Because of the level of disassembly needed
to deal with LEDs, I'm hoping that it's a power board issue.
I looked around at ShopJimmy, and they are out of stock of
most things. I don't know what might be available on Ebay.
> The HU series *does* have intermittent issues with LEDs,
> either from individual LEDs or the interconnects on the
> strips. Sometimes you can change just the bad LEDs or
> hardwire the interconnects if there is a voltage drop
> across them, but the best option is to order the
> complete set of strips from someone like ShopJimmy.
LEDs are connected to power lines, or how the lines are
interconnected. Because of the level of disassembly needed
to deal with LEDs, I'm hoping that it's a power board issue.
I looked around at ShopJimmy, and they are out of stock of
most things. I don't know what might be available on Ebay.
Charles Lucas
Jul 21, 2022, 10:31:59 PM7/21/22
to
https://www.samsung.com/ca/support/model/UN55HU6840FXZC/
Click on the Manuals and downloads link on the menu selection you can choose
from.
>
> Well, any guidance would be appreciated.
strip.
ohg...@gmail.com
Jul 22, 2022, 10:07:59 AM7/22/22
to
ohg...@gmail.com
Jul 22, 2022, 10:10:52 AM7/22/22
to
On Thursday, July 21, 2022 at 9:21:16 PM UTC-4, Peabody wrote:
https://www.shopjimmy.com/samsung-bn96-34251a-bn96-34252a-led-backlight-strips-14/#mz-expanded-view-1444464375404
legg
Jul 22, 2022, 10:59:45 AM7/22/22
to
On Thu, 21 Jul 2022 15:04:24 -0700, Jeff Liebermann <je...@cruzio.com>
You're right. It looks like only Panasonoc, Sanyo and Sony
sets have a side-button power-on reset.
For Samsung audio/no image symptoms, the 'troubleshooting
tree' branches out as
-check LVDS connector
-change tcon
-change main board
Not very helpful. Unlikely it's a power supply issue, but
bulging caps are common, even so, on sets of this era.
Some TVs are too smart for their own good.
Haven't had one for personal use since 1978.
Bloody waste of time.
RL
sets have a side-button power-on reset.
For Samsung audio/no image symptoms, the 'troubleshooting
tree' branches out as
-check LVDS connector
-change tcon
-change main board
Not very helpful. Unlikely it's a power supply issue, but
bulging caps are common, even so, on sets of this era.
Some TVs are too smart for their own good.
Haven't had one for personal use since 1978.
Bloody waste of time.
RL
legg
Jul 22, 2022, 11:25:58 AM7/22/22
to
On Thu, 21 Jul 2022 15:04:24 -0700, Jeff Liebermann <je...@cruzio.com>
a 'Factory Mode', which can be unproductive, if not downright
destructive, if the screen isn't visible. Remote botton
functions may not as labelled.
So unless the manual says it, don't do it.
RL
wrote:
>On Thu, 21 Jul 2022 15:36:36 -0400, legg <le...@nospam.magma.ca> wrote:
>
>>On Wed, 20 Jul 2022 21:45:35 -0700, Jeff Liebermann <je...@cruzio.com>
>>wrote:
>>
>>>UN55HU6840
>>
>>You might try a manual 'reset to factory', or a USB
>>re-flash. These procedures don't need an active screen
>>or remote.
>
>I looked at the user manual and searched the internet for such a
>procedure. There are two resets. One for resetting the smart hub and
>another for resetting everything except the network settings. Both
>are access from the setting menu which requires seeing something on
>the screen. There are probably instruction for a factory reset
>without using the remote or screen, but I couldn't find them.
>
Some sets have a power-on keypress sequence that invokes
>On Thu, 21 Jul 2022 15:36:36 -0400, legg <le...@nospam.magma.ca> wrote:
>
>>On Wed, 20 Jul 2022 21:45:35 -0700, Jeff Liebermann <je...@cruzio.com>
>>wrote:
>>
>>>UN55HU6840
>>
>>You might try a manual 'reset to factory', or a USB
>>re-flash. These procedures don't need an active screen
>>or remote.
>
>I looked at the user manual and searched the internet for such a
>procedure. There are two resets. One for resetting the smart hub and
>another for resetting everything except the network settings. Both
>are access from the setting menu which requires seeing something on
>the screen. There are probably instruction for a factory reset
>without using the remote or screen, but I couldn't find them.
>
a 'Factory Mode', which can be unproductive, if not downright
destructive, if the screen isn't visible. Remote botton
functions may not as labelled.
So unless the manual says it, don't do it.
RL
legg
Jul 22, 2022, 11:38:07 AM7/22/22
to
From an old web search:
Factory Resets Listing
Over time, I have created a listing of manufacturers and their factory
reset/factory mode procedures that may help others. This list is from
my own experience, and is by no means complete for any given
manufacturer. Some have been found by searching the internet, some by
trial and error. I hope some may find this information useful
**** WARNING!!!! ******
Some of these procedures may allow you to enter factory service modes.
IF YOU DO NOT KNOW WHAT YOU ARE DOING, DO NOT MAKE CHANGES TO SETTINGS
IN FACTORY MODES!! Improper settings may cause undesired operation,
and could result in a situation where your TV cannot boot/turn on.
YOU ARE USING THESE PROCEDURES AT YOUR OWN RISK!!
Factory Resets / modes
For all listed procedures, start with TV on, in TV mode, unless
otherwise instructed. After procedure is complete, unplug set and
re-plug in to finish reset.
If more than one procedure is listed for a given manufacturer, try the
different ones until you see which one works for your set.
Coby:****************************************-
Enter menu, hi-lite “audio” then enter 8893
mode/source 2580 select “other setting”,select “shipment” then yes,
after it exits service menu you need to power set off.
Dynex ****************************************-
source/input 2580
hold vol down on tv and hold #1 button on remote, vol will jump to
halfway and set shuts off. Turn back on have 1st time setup screen.
source/input 2580
menu 1999 (tv is on)
Element ****************************************
menu 0000
menu 1147
Haier ******************************************
pull up menu, hi-lite “audio” then enter 8893
Hisense *****************************************
In customer menu go to”Parental” enter 0000 then select”Clean All”
then power the set off and back on and first time setup menu will be
there.
For some models, same as above model except in menu it is labeled
“Lock”
Insignia *****************************************-
input 2580 (tv is on)
Mitsubishi ****************************************
Menu 123 or menu 2470 (tv is on)
Panasonic
Hold vol- on TV, press and hold menu button on remote
Philips ******************************************
Push menu, select”Features”then select”current software info” push
062596-info on remote then push info again then red”initialize appears
and changes color then complete. Push power button to exit
TV is on,push 062596-info on remote,then push info again,
red”initialized”appears it turns green when completed, then push power
button to exit
Polariod *****************************************-
Hold vol- and chan- or hold vol+ and chan+ (tv is on)
Proscan ******************************************
In customer menu go to setup,select parental control menu, enter 0000
then select “clear channel list”.
RCA *******************************************-
Menu 1147
Sanyo *******************************************
hold vol down on TV, press and hold #1 button on remote, vol will jump
to halfway and set shuts off. Turn back on have 1st time setup screen.
Samsung *****************************************-
Mute 182 power (tv is off)
(On some models, Factory Reset is on this menu, on some, you must go
into the “Options” submenu
Seiki ********************************************-
Menu 0000
Sharp ********************************************
(Note – On Sharp models, you will need to look through the menus to
find the reset option)
menu 1999
menu, 3481
menu 1147
while holding vol– & input buttons on tv plug in set when “k” appears
push vol– & chan-
Sony *********************************************
Hold “arrow up” on remote and push power button on tv (tv is on)
Symphony *****************************************-
Source/input 2580
Toshiba ******************************************-
on Menu, select “Installation”, then “System Information” press the
right arrow button, (“System Information” will change to “Factory
Reset” or something similar) follow on-screen instructions
Vision Quest ***************************************-
Source/input 2580
Vizio ********************************************
In customer menu under “Help” tab is Factory Default enter 0000
*****************************************************8
Vestel (most):
Menu 4725 then select "RESET"
Samsung (European):
Power off, Info - Menu - Mute - Power, then find factory reset and
execute option.
LG/Zenith:
Hold MENU on TV and MENU on remote for 5~10 seconds, then select reset
option.
NEC:
While powering on hold "MENU" or "INPUT" on TV, depending on model.
(Only disables error lock out/buffer and puts TV in temporary service
mode.)
To reset to factory, on remote, Off Timer - Menu - Exit - Off Timer,
then select reset option.
***********************************************************8
Vizio Service Menu Method 1
1. Turn The TV off.
2. Press and hold the {CH +} & {CH -} buttons on the TV.
3. Then press and release the {POWER} button on the TV.
4. Release the {CH +} & {CH -} buttons.
5. Now press the {MENU} button on the remote.
6. You should get your regular menu up, but with a "F" in the bottom
right corner of the menu (This is for factory).
7. Press and hold the {MENU} button for few seconds.
8. The Service Menu will be displayed.
Vizio Service Menu Method 2
1. Turn The TV off.
2. Press and hold the {CH +} & {CH -} buttons on the TV.
3. Then press and hold the {POWER} button on the TV.
4. Keep all three buttons pressed for few seconds.
5. Now press the {MENU} button on the remote.
6. You should get your regular menu up, but with a "F" in the bottom
right corner of the menu (This is for factory).
7. Press and hold the {MENU} button for few seconds.
8. The Service Menu will be displayed.
Vizio Service Menu Method 3
1. Press and hold the {EXIT} button on the remote for 3 seconds then
release it.
2. Then press the {1} {2} {3} buttons on the remote.
3. To exit, press the {EXIT} button.
---------------------------------------------------------------
GV42L FHDTV10A / JV50 / SV42 / SV320XVT / SV370XVT / SV420M / SV470M /
SV420XVT1A / SV470XVT1A /
VECO320L1A / VO22L / VO32 / VO37 / VO47L / VOJ320 / VOJ370 / VP322 /
VP42 HDTV20A / VP422 / VS420LF1A /
VU42 / VW32 / VW37 / VW42 / VX20 / VX32 / VX37 HDTV10A /VX42
Push "Menu" on remote and then push "Vol-" and "Input" on keypad
GV46 / P50HDM / P50HDTV10A
Press "Ch-" and "Ch+" buttons together once on keypad
GV42 / L42 / VP42HDTV10A / VP50 / VX37
Press and release "Menu" on keypad. Hold "Ch-" and "Ch+" buttons on
keypad, then hold "Menu" on remote.
P42
Hold "Ch+" and "Ch-" along with "Power" on keypad. OSD will show "F"
on right bottom portion of OSD.
VM60P
Press "Info" on remote, then press "Right Arrow," "Down Arrow," "Left
Arrow," "Up Arrow," "Right Arrow."
The TV will show "Enter Factory Mode." Press "Menu" after message
disappears and go do to "Setup."
GV47
Press "Menu" then press the following combination: "Info," "8," "2,"
"0," "6."
SV420M / SV470M / VF550M / VF550XVT1A / VF551XVT / VL260M / VL320M /
VL420M / VL470M / VO320E /
VO320EP8 / VO370M / VO420E / VP504 / VP505
Press "Menu," and then press "2," "4," "8," "9."
SV420M / SV470M / VF550M / VF550XVT1A / VF551XVT / VL260M / VL320M /
VL420M / VL470M / VO320E /
VO320EP8 / VO370M / VO420E / VP504 / VP505
Press "Menu," and then press "2," "4," "8," "9."
VA19 / VA22LF / VA220E / VA26
Press "Menu" and then press the following combination: "0," "6," "2,"
"5," "9," "6"
VA320E / VA320M / VA370M / VT420M / VT470M
Press "Menu" and then press the following combination: "1," "9," "9,"
"1"
VW22 / VS370E
Press "Mute" once OR "-" twice (the dash next to the "0") and then
press the following combination: "9," "8," "7," "6"
**************************************************
PANASONIC lcd and plasma TV's service menu (factory reset is done via
menu)
press and hold volume down (on tv panel)
while still holding vol- press i (info botton) on remote three times
service menu starts up - scrolling pages is done by color botton
(green if not mistaking
*usefull for people who know what they are doing (not me at the
moment)
-i found it usfull only for white wash for plasma TV's (just scroll
throuh the menu untill you see the white wash apears
exit the menu by turning off the TV
***************************************
Here in South Africa - and I guess most of the Southern Hemisphere -
we are reluctantly getting used to a myriad of Chinese sets with
Anglic-sounding names like 'Ultravision' and Germanic ones like
'Bauer'.
Inside they are mostly Chinese generic boards and most respond to the
following for factory mode:
Hold down volume minus (Volume down) on set and press 'recall' on
remote.
'Recall' is the button that activates the channel number and clock
onscreen.
After you have made your changes, in most cases, pressing 'power' on
the remote will clear the factory mode.
On some models pressing the 'AV' button will revert things to normal
operation.
In rare cases, the sequence first described above - (Vol - on set and
recall on remote) will have to be repeated at least once more.
If none of the above methods works, try using a universal remote -
best one that has a LOT of in-built models..!
Search through the available models looking for any that suddenly
causes the set to change channels.
Lock this setting into the remote and press '2'.
Factory mode should appear.
BE WARNED that NONE of the remote's buttons will function normally!
Use the front panel buttons to scroll through available menus and make
any changes. Power off set to revert to normal functioning.
***************************************************
Lamp Error Reset for Sharp LCD TV.
With power LED off (TV in fake standby or AC power plug removed) hold
Vol- and SOURCE/INPUT.
Power on the TV. Do not release the buttons.
This may take up to 20 seconds.
Look for a letter "K" on the side of the screen when it powers up. If
this appears, continue. If not, repeat the above procedure.
Press CH- and VOL- to access service menu. See if LAMP ERROR appears
in listing. If so, then a reset procedure is necessary
Page through the menus looking for "L ERR RESET". Execute the option
(highlight and press OK.)
Power off the TV (TV in fake standby or AC power plug removed)
Hold Vol- and SOURCE/INPUT.
Power on the TV. Do not release the buttons.
No "K" should appear.
Power off the TV.
The TV should now be fixed.
**********************************************
https://factory-reset.com/
****************************************
Hisense TV.....
goto menu, sound, balance set to "0" then press 1969
be carefull....
********************************************
Factory Resets Listing
Over time, I have created a listing of manufacturers and their factory
reset/factory mode procedures that may help others. This list is from
my own experience, and is by no means complete for any given
manufacturer. Some have been found by searching the internet, some by
trial and error. I hope some may find this information useful
**** WARNING!!!! ******
Some of these procedures may allow you to enter factory service modes.
IF YOU DO NOT KNOW WHAT YOU ARE DOING, DO NOT MAKE CHANGES TO SETTINGS
IN FACTORY MODES!! Improper settings may cause undesired operation,
and could result in a situation where your TV cannot boot/turn on.
YOU ARE USING THESE PROCEDURES AT YOUR OWN RISK!!
Factory Resets / modes
For all listed procedures, start with TV on, in TV mode, unless
otherwise instructed. After procedure is complete, unplug set and
re-plug in to finish reset.
If more than one procedure is listed for a given manufacturer, try the
different ones until you see which one works for your set.
Coby:****************************************-
Enter menu, hi-lite “audio” then enter 8893
mode/source 2580 select “other setting”,select “shipment” then yes,
after it exits service menu you need to power set off.
Dynex ****************************************-
source/input 2580
hold vol down on tv and hold #1 button on remote, vol will jump to
halfway and set shuts off. Turn back on have 1st time setup screen.
source/input 2580
menu 1999 (tv is on)
Element ****************************************
menu 0000
menu 1147
Haier ******************************************
pull up menu, hi-lite “audio” then enter 8893
Hisense *****************************************
In customer menu go to”Parental” enter 0000 then select”Clean All”
then power the set off and back on and first time setup menu will be
there.
For some models, same as above model except in menu it is labeled
“Lock”
Insignia *****************************************-
input 2580 (tv is on)
Mitsubishi ****************************************
Menu 123 or menu 2470 (tv is on)
Panasonic
Hold vol- on TV, press and hold menu button on remote
Philips ******************************************
Push menu, select”Features”then select”current software info” push
062596-info on remote then push info again then red”initialize appears
and changes color then complete. Push power button to exit
TV is on,push 062596-info on remote,then push info again,
red”initialized”appears it turns green when completed, then push power
button to exit
Polariod *****************************************-
Hold vol- and chan- or hold vol+ and chan+ (tv is on)
Proscan ******************************************
In customer menu go to setup,select parental control menu, enter 0000
then select “clear channel list”.
RCA *******************************************-
Menu 1147
Sanyo *******************************************
hold vol down on TV, press and hold #1 button on remote, vol will jump
to halfway and set shuts off. Turn back on have 1st time setup screen.
Samsung *****************************************-
Mute 182 power (tv is off)
(On some models, Factory Reset is on this menu, on some, you must go
into the “Options” submenu
Seiki ********************************************-
Menu 0000
Sharp ********************************************
(Note – On Sharp models, you will need to look through the menus to
find the reset option)
menu 1999
menu, 3481
menu 1147
while holding vol– & input buttons on tv plug in set when “k” appears
push vol– & chan-
Sony *********************************************
Hold “arrow up” on remote and push power button on tv (tv is on)
Symphony *****************************************-
Source/input 2580
Toshiba ******************************************-
on Menu, select “Installation”, then “System Information” press the
right arrow button, (“System Information” will change to “Factory
Reset” or something similar) follow on-screen instructions
Vision Quest ***************************************-
Source/input 2580
Vizio ********************************************
In customer menu under “Help” tab is Factory Default enter 0000
*****************************************************8
Vestel (most):
Menu 4725 then select "RESET"
Samsung (European):
Power off, Info - Menu - Mute - Power, then find factory reset and
execute option.
LG/Zenith:
Hold MENU on TV and MENU on remote for 5~10 seconds, then select reset
option.
NEC:
While powering on hold "MENU" or "INPUT" on TV, depending on model.
(Only disables error lock out/buffer and puts TV in temporary service
mode.)
To reset to factory, on remote, Off Timer - Menu - Exit - Off Timer,
then select reset option.
***********************************************************8
Vizio Service Menu Method 1
1. Turn The TV off.
2. Press and hold the {CH +} & {CH -} buttons on the TV.
3. Then press and release the {POWER} button on the TV.
4. Release the {CH +} & {CH -} buttons.
5. Now press the {MENU} button on the remote.
6. You should get your regular menu up, but with a "F" in the bottom
right corner of the menu (This is for factory).
7. Press and hold the {MENU} button for few seconds.
8. The Service Menu will be displayed.
Vizio Service Menu Method 2
1. Turn The TV off.
2. Press and hold the {CH +} & {CH -} buttons on the TV.
3. Then press and hold the {POWER} button on the TV.
4. Keep all three buttons pressed for few seconds.
5. Now press the {MENU} button on the remote.
6. You should get your regular menu up, but with a "F" in the bottom
right corner of the menu (This is for factory).
7. Press and hold the {MENU} button for few seconds.
8. The Service Menu will be displayed.
Vizio Service Menu Method 3
1. Press and hold the {EXIT} button on the remote for 3 seconds then
release it.
2. Then press the {1} {2} {3} buttons on the remote.
3. To exit, press the {EXIT} button.
---------------------------------------------------------------
GV42L FHDTV10A / JV50 / SV42 / SV320XVT / SV370XVT / SV420M / SV470M /
SV420XVT1A / SV470XVT1A /
VECO320L1A / VO22L / VO32 / VO37 / VO47L / VOJ320 / VOJ370 / VP322 /
VP42 HDTV20A / VP422 / VS420LF1A /
VU42 / VW32 / VW37 / VW42 / VX20 / VX32 / VX37 HDTV10A /VX42
Push "Menu" on remote and then push "Vol-" and "Input" on keypad
GV46 / P50HDM / P50HDTV10A
Press "Ch-" and "Ch+" buttons together once on keypad
GV42 / L42 / VP42HDTV10A / VP50 / VX37
Press and release "Menu" on keypad. Hold "Ch-" and "Ch+" buttons on
keypad, then hold "Menu" on remote.
P42
Hold "Ch+" and "Ch-" along with "Power" on keypad. OSD will show "F"
on right bottom portion of OSD.
VM60P
Press "Info" on remote, then press "Right Arrow," "Down Arrow," "Left
Arrow," "Up Arrow," "Right Arrow."
The TV will show "Enter Factory Mode." Press "Menu" after message
disappears and go do to "Setup."
GV47
Press "Menu" then press the following combination: "Info," "8," "2,"
"0," "6."
SV420M / SV470M / VF550M / VF550XVT1A / VF551XVT / VL260M / VL320M /
VL420M / VL470M / VO320E /
VO320EP8 / VO370M / VO420E / VP504 / VP505
Press "Menu," and then press "2," "4," "8," "9."
SV420M / SV470M / VF550M / VF550XVT1A / VF551XVT / VL260M / VL320M /
VL420M / VL470M / VO320E /
VO320EP8 / VO370M / VO420E / VP504 / VP505
Press "Menu," and then press "2," "4," "8," "9."
VA19 / VA22LF / VA220E / VA26
Press "Menu" and then press the following combination: "0," "6," "2,"
"5," "9," "6"
VA320E / VA320M / VA370M / VT420M / VT470M
Press "Menu" and then press the following combination: "1," "9," "9,"
"1"
VW22 / VS370E
Press "Mute" once OR "-" twice (the dash next to the "0") and then
press the following combination: "9," "8," "7," "6"
**************************************************
PANASONIC lcd and plasma TV's service menu (factory reset is done via
menu)
press and hold volume down (on tv panel)
while still holding vol- press i (info botton) on remote three times
service menu starts up - scrolling pages is done by color botton
(green if not mistaking
*usefull for people who know what they are doing (not me at the
moment)
-i found it usfull only for white wash for plasma TV's (just scroll
throuh the menu untill you see the white wash apears
exit the menu by turning off the TV
***************************************
Here in South Africa - and I guess most of the Southern Hemisphere -
we are reluctantly getting used to a myriad of Chinese sets with
Anglic-sounding names like 'Ultravision' and Germanic ones like
'Bauer'.
Inside they are mostly Chinese generic boards and most respond to the
following for factory mode:
Hold down volume minus (Volume down) on set and press 'recall' on
remote.
'Recall' is the button that activates the channel number and clock
onscreen.
After you have made your changes, in most cases, pressing 'power' on
the remote will clear the factory mode.
On some models pressing the 'AV' button will revert things to normal
operation.
In rare cases, the sequence first described above - (Vol - on set and
recall on remote) will have to be repeated at least once more.
If none of the above methods works, try using a universal remote -
best one that has a LOT of in-built models..!
Search through the available models looking for any that suddenly
causes the set to change channels.
Lock this setting into the remote and press '2'.
Factory mode should appear.
BE WARNED that NONE of the remote's buttons will function normally!
Use the front panel buttons to scroll through available menus and make
any changes. Power off set to revert to normal functioning.
***************************************************
Lamp Error Reset for Sharp LCD TV.
With power LED off (TV in fake standby or AC power plug removed) hold
Vol- and SOURCE/INPUT.
Power on the TV. Do not release the buttons.
This may take up to 20 seconds.
Look for a letter "K" on the side of the screen when it powers up. If
this appears, continue. If not, repeat the above procedure.
Press CH- and VOL- to access service menu. See if LAMP ERROR appears
in listing. If so, then a reset procedure is necessary
Page through the menus looking for "L ERR RESET". Execute the option
(highlight and press OK.)
Power off the TV (TV in fake standby or AC power plug removed)
Hold Vol- and SOURCE/INPUT.
Power on the TV. Do not release the buttons.
No "K" should appear.
Power off the TV.
The TV should now be fixed.
**********************************************
https://factory-reset.com/
****************************************
Hisense TV.....
goto menu, sound, balance set to "0" then press 1969
be carefull....
********************************************
Peabody
Jul 22, 2022, 2:06:13 PM7/22/22
to
Ok, this is the first hands-on update.
The TV arrived this morning. I hooked it up to my computer via HDMI (it
was, of course, the last HDMI connector I tried) and I get audio. Running
the flashlight test, I can see the icons on my desktop and any video I play
on the computer. The screen is dark, but as I understand it, passing the
flashlight test means the video is working, and it's the backlight that's
out.
However, the owner brought his paperwork with him, and I found the invoice
for the repair done in 2017. He says the symptoms were the same then as
now. The invoice says they replaced the main board, #BN94-08076A. They
charged $135 for the part.
I doubt I could repair the main board, but I think it's still worth taking
a look. After all, I don't know that the invoice reflects what they
actually did to fix it. And even if it was the main board last time, it
could be something else this time.
Perhaps it will be obvious when I take the cover off, but it seems to me
that one test would be to disconnnect the main board from the power board,
and see if the LEDs light up. If they do, then it is the main board that's
keeping the LEDs off. If they don't then it's either the power board or
the LEDs. But is it possible to test what the voltage should be on the
lines driving the LEDs? If the LEDs are in series, then it has to be high
enough to drive all of them, so maybe 150V or more. Is that right? What
I'm looking for is a way to test whether the power board is working or not.
Well maybe the voltages will be printed on the board. In the videos it
looks like they might be.
I'm just not clear how the LEDs are driven. Are they like the old
Christmas tree lights - all in series, so if one burns out they all go
dark? Or are they in parallel, or what?
Still no success finding a schematic or service manual.
The TV arrived this morning. I hooked it up to my computer via HDMI (it
was, of course, the last HDMI connector I tried) and I get audio. Running
the flashlight test, I can see the icons on my desktop and any video I play
on the computer. The screen is dark, but as I understand it, passing the
flashlight test means the video is working, and it's the backlight that's
out.
However, the owner brought his paperwork with him, and I found the invoice
for the repair done in 2017. He says the symptoms were the same then as
now. The invoice says they replaced the main board, #BN94-08076A. They
charged $135 for the part.
I doubt I could repair the main board, but I think it's still worth taking
a look. After all, I don't know that the invoice reflects what they
actually did to fix it. And even if it was the main board last time, it
could be something else this time.
Perhaps it will be obvious when I take the cover off, but it seems to me
that one test would be to disconnnect the main board from the power board,
and see if the LEDs light up. If they do, then it is the main board that's
keeping the LEDs off. If they don't then it's either the power board or
the LEDs. But is it possible to test what the voltage should be on the
lines driving the LEDs? If the LEDs are in series, then it has to be high
enough to drive all of them, so maybe 150V or more. Is that right? What
I'm looking for is a way to test whether the power board is working or not.
Well maybe the voltages will be printed on the board. In the videos it
looks like they might be.
I'm just not clear how the LEDs are driven. Are they like the old
Christmas tree lights - all in series, so if one burns out they all go
dark? Or are they in parallel, or what?
Still no success finding a schematic or service manual.
ohg...@gmail.com
Jul 22, 2022, 2:56:39 PM7/22/22
to
On Friday, July 22, 2022 at 2:06:13 PM UTC-4, Peabody wrote:
> I'm just not clear how the LEDs are driven. Are they like the old
> Christmas tree lights - all in series, so if one burns out they all go
> dark? Or are they in parallel, or what?
In *this* model, they're all in series and it's a one channel LED system - one LED or if one interconnect opens, no light.
> I'm just not clear how the LEDs are driven. Are they like the old
> Christmas tree lights - all in series, so if one burns out they all go
> dark? Or are they in parallel, or what?
> Still no success finding a schematic or service manual.
An easy test on this model is to unplug the harness between the main board and the power supply and plug in the AC. With the main disconnected, the on/off line pull-up resistor will put the power supply into free-run, including the LED drive. If the back light comes on, the main *or* the power supply board is bad. If the LEDs come on, post that and I'll walk you through isolating the main or the power supply.
If the LEDs don't come on with the main disconnected and the AC applied which is what I'm confident you'll find, measure between BD9101 (either side) and J858 on the top side of the board near the LED harness. Should be more than 150V-300V (depending on whether this uses 3V or 6V LEDs) there between those jumpers. If it's there or higher, the problem is inside the display - either a bad LED or open interconnect between the LED strips.
No voltage or low voltage between those points? Bad power supply.
Peabody
Jul 22, 2022, 5:32:13 PM7/22/22
to
ohg...@gmail.com says...
> An easy test on this model is to unplug the harness
> between the main board and the power supply and plug in
> the AC. With the main disconnected, the on/off line
> pull-up resistor will put the power supply into
> free-run, including the LED drive. If the back light
> comes on, the main *or* the power supply board is bad.
> If the LEDs come on, post that and I'll walk you through
> isolating the main or the power supply.
Ok, so the main board controls the brightness of the LEDs
through some kind of PWM signal to the power board. If so,
then it seems to me if the LEDs fire up when the main board
is disconnected, then the main board is the problem -
something is grounding that signal line. It seems the power
board has proved it's ok.
But it does occur to me that if nothing else on the main
board is bad, then you could replace the PWM signal with
something coming out of an Arduino. :-)
> If the LEDs don't come on with the main disconnected and
> the AC applied which is what I'm confident you'll find,
> measure between BD9101 (either side) and J858 on the top
> side of the board near the LED harness. Should be more
> than 150V-300V (depending on whether this uses 3V or 6V
> LEDs) there between those jumpers. If it's there or
> higher, the problem is inside the display - either a bad
> LED or open interconnect between the LED strips.
> No voltage or low voltage between those points? Bad
> power supply.
Yes, that makes sense. I don't have a lab power supply, but
if I could borrow one, it seems another test would be to
disconnect the LED strips and reconnect them to a power
supply. You could ramp up the voltage to see if the LEDs
light up at some point. If they do, then they aren't the
problem. If they don't, something is open.
> An easy test on this model is to unplug the harness
> between the main board and the power supply and plug in
> the AC. With the main disconnected, the on/off line
> pull-up resistor will put the power supply into
> free-run, including the LED drive. If the back light
> comes on, the main *or* the power supply board is bad.
> If the LEDs come on, post that and I'll walk you through
> isolating the main or the power supply.
through some kind of PWM signal to the power board. If so,
then it seems to me if the LEDs fire up when the main board
is disconnected, then the main board is the problem -
something is grounding that signal line. It seems the power
board has proved it's ok.
But it does occur to me that if nothing else on the main
board is bad, then you could replace the PWM signal with
something coming out of an Arduino. :-)
> If the LEDs don't come on with the main disconnected and
> the AC applied which is what I'm confident you'll find,
> measure between BD9101 (either side) and J858 on the top
> side of the board near the LED harness. Should be more
> than 150V-300V (depending on whether this uses 3V or 6V
> LEDs) there between those jumpers. If it's there or
> higher, the problem is inside the display - either a bad
> LED or open interconnect between the LED strips.
> No voltage or low voltage between those points? Bad
> power supply.
if I could borrow one, it seems another test would be to
disconnect the LED strips and reconnect them to a power
supply. You could ramp up the voltage to see if the LEDs
light up at some point. If they do, then they aren't the
problem. If they don't, something is open.
legg
Jul 22, 2022, 8:47:42 PM7/22/22
to
issue.
RL
Peabody
Jul 23, 2022, 9:27:02 AM7/23/22
to
ohg...@gmail.com says...
> In *this* model, they're all in series and it's a one
> channel LED system - one LED or if one interconnect
> opens, no light.
On the ShopJimmy page for this model, it shows the LED
package as seven strips of eight LEDs, plus seven strips of
five LEDs. That's 91 LEDs. If they're all in series, then
3V LEDs would need 273V. So perhaps the strips are wired in
some parallel configuration?
I'm starting on the diagnostics this morning with a neighbor
who I discovered used to work for TI back in the day.
One of the ShopJimmy videos say flatly that if you pass the
flashlight test, with audio, then a dark screen is either
the power board or the LEDs. I guess that's not absolutely
always true, but seems logical to me. I'm hoping for the
power supply to be the problem. I'm not sure I would be
willing to tackle the LEDs. I've watched those videos, and
it's a major undertaking, with lots of opportunities to break
things.
> In *this* model, they're all in series and it's a one
> channel LED system - one LED or if one interconnect
> opens, no light.
package as seven strips of eight LEDs, plus seven strips of
five LEDs. That's 91 LEDs. If they're all in series, then
3V LEDs would need 273V. So perhaps the strips are wired in
some parallel configuration?
I'm starting on the diagnostics this morning with a neighbor
who I discovered used to work for TI back in the day.
One of the ShopJimmy videos say flatly that if you pass the
flashlight test, with audio, then a dark screen is either
the power board or the LEDs. I guess that's not absolutely
always true, but seems logical to me. I'm hoping for the
power supply to be the problem. I'm not sure I would be
willing to tackle the LEDs. I've watched those videos, and
it's a major undertaking, with lots of opportunities to break
things.
Adrian Caspersz
Jul 23, 2022, 9:36:15 AM7/23/22
to
--
Adrian C
Peabody
Jul 23, 2022, 12:33:56 PM7/23/22
to
Well, I had a major setback trying to diagnose the repair. Last night I
set it on the dining room table, face down, and this morning I did the
flashlight and audio test again before even taking the back cover off,
just to confirm the video and audio were still working. But after about 30
minutes, the TV started working again. All the backlights came on, and the
picture is perfect. This is the behavior the owner reported - it might
get backlight at any time, or it might not.
I measured 267V between BD9101 and J858, so that's the benchmark in case it
dies again.
So I don't know how you diagnose anything when it's working properly. We
tried tapping on every part and connector on the power board, but not even
a flicker in the lights.
Both sides of the power board look perfect - not a hint of a bad solder, no
domed capacitors, no brown marks. The connector to the LEDs (CLN802) has 7
black wires and one blue wire, and a legend that doesn't seem to match the
connector.
In any case, I will let it cool down, and see how it powers up. I guess I
could remove and test all the electrolytics, but there are a lot of them.
Same for the diodes. But it seems it could be anything. Major bummer that
it's working. :-)
set it on the dining room table, face down, and this morning I did the
flashlight and audio test again before even taking the back cover off,
just to confirm the video and audio were still working. But after about 30
minutes, the TV started working again. All the backlights came on, and the
picture is perfect. This is the behavior the owner reported - it might
get backlight at any time, or it might not.
I measured 267V between BD9101 and J858, so that's the benchmark in case it
dies again.
So I don't know how you diagnose anything when it's working properly. We
tried tapping on every part and connector on the power board, but not even
a flicker in the lights.
Both sides of the power board look perfect - not a hint of a bad solder, no
domed capacitors, no brown marks. The connector to the LEDs (CLN802) has 7
black wires and one blue wire, and a legend that doesn't seem to match the
connector.
In any case, I will let it cool down, and see how it powers up. I guess I
could remove and test all the electrolytics, but there are a lot of them.
Same for the diodes. But it seems it could be anything. Major bummer that
it's working. :-)
ohg...@gmail.com
Jul 23, 2022, 12:49:23 PM7/23/22
to
On Saturday, July 23, 2022 at 9:27:02 AM UTC-4, Peabody wrote:
> ohg...@gmail.com says...
> > In *this* model, they're all in series and it's a one
> > channel LED system - one LED or if one interconnect
> > opens, no light.
> On the ShopJimmy page for this model, it shows the LED
> package as seven strips of eight LEDs, plus seven strips of
> five LEDs. That's 91 LEDs. If they're all in series, then
> 3V LEDs would need 273V. So perhaps the strips are wired in
> some parallel configuration?
I have an HU board here in front of me that I grabbed the standby IC out of for another job, and I have the LED voltage marked as 325/375V on the BD9101 ferrite jumper (with respect to cold ground. Use the mounting screws for ground). I have seen a bunch of TVs that use a series/parallel arrangement, but I can't recall Samsung ever doing that.
> ohg...@gmail.com says...
> > In *this* model, they're all in series and it's a one
> > channel LED system - one LED or if one interconnect
> > opens, no light.
> On the ShopJimmy page for this model, it shows the LED
> package as seven strips of eight LEDs, plus seven strips of
> five LEDs. That's 91 LEDs. If they're all in series, then
> 3V LEDs would need 273V. So perhaps the strips are wired in
> some parallel configuration?
> I'm starting on the diagnostics this morning with a neighbor
> who I discovered used to work for TI back in the day.
>
> One of the ShopJimmy videos say flatly that if you pass the
> flashlight test, with audio, then a dark screen is either
> the power board or the LEDs. I guess that's not absolutely
> always true, but seems logical to me. I'm hoping for the
> power supply to be the problem. I'm not sure I would be
> willing to tackle the LEDs. I've watched those videos, and
> it's a major undertaking, with lots of opportunities to break
> things.
ohg...@gmail.com
Jul 23, 2022, 1:42:02 PM7/23/22
to
On Saturday, July 23, 2022 at 12:33:56 PM UTC-4, Peabody wrote:
> Well, I had a major setback trying to diagnose the repair. Last night I
> set it on the dining room table, face down, and this morning I did the
> flashlight and audio test again before even taking the back cover off,
> just to confirm the video and audio were still working. But after about 30
> minutes, the TV started working again. All the backlights came on, and the
> picture is perfect. This is the behavior the owner reported - it might
> get backlight at any time, or it might not.
>
> I measured 267V between BD9101 and J858, so that's the benchmark in case it
> dies again.
Keep a meter on it all the time. If it has a min/max recording feature, connect a DVD player and leave it on the title screen so the TV doesn't dynamically adjust the back light to scene content or time out and shut off. Check the max voltage every once in a while. If your baseline drifts more than a tenth or so with no change of picture content, it indicates a failing LED (they do intermitt both towards open and leaky) or a bad interconnect between the A/B sections of the LED strips or where the LED strips plug into the main feed strip.
> Well, I had a major setback trying to diagnose the repair. Last night I
> set it on the dining room table, face down, and this morning I did the
> flashlight and audio test again before even taking the back cover off,
> just to confirm the video and audio were still working. But after about 30
> minutes, the TV started working again. All the backlights came on, and the
> picture is perfect. This is the behavior the owner reported - it might
> get backlight at any time, or it might not.
>
> I measured 267V between BD9101 and J858, so that's the benchmark in case it
> dies again.
> So I don't know how you diagnose anything when it's working properly.
Sometimes we have to hard wire all the interconnects - if just one is bad, another will follow eventually. It's not intuitive but poor connections *don't* show much if any change in brightness even when tapped on as the LED drive controller is extremely fast and compensates immediately for any change in load impedance. Only when the connection is bad enough to cause the controller IC to detect either an overvoltage or undercurrent condition does the LED array shut down.
Ralph Mowery
Jul 23, 2022, 3:41:36 PM7/23/22
to
In article <20220723-1...@Peabody.ssl-us.astraweb.com>,
waybackNO...@yahoo.com says...
If it does not power up, you may try heating the capacitors one at a
time. I have seen that work on equipment that comes on after the set is
powered up for a while if the capacitor is bad.
waybackNO...@yahoo.com says...
time. I have seen that work on equipment that comes on after the set is
powered up for a while if the capacitor is bad.
Jeff Liebermann
Jul 23, 2022, 5:53:59 PM7/23/22
to
On Sat, 23 Jul 2022 11:33:53 -0500, Peabody
<waybackNO...@yahoo.com> wrote:
>So I don't know how you diagnose anything when it's working properly. We
>tried tapping on every part and connector on the power board, but not even
>a flicker in the lights.
Intermittents are a PITA. I'll spare you my guess of the day. The
<waybackNO...@yahoo.com> wrote:
>So I don't know how you diagnose anything when it's working properly. We
>tried tapping on every part and connector on the power board, but not even
>a flicker in the lights.
way I used to troubleshoot intermittents is heating with a hot air gun
and cooling with freeze spray in a can. Whatever connection is
intermittent, is going to move when it gets hot or cold, either making
the connections, or as in this case, breaking the connection. Don't
use to much cooling or heating. Dropping the temperature below the
dew point will condense water all over the board. Heating the PCB too
much will melt plastic parts. If you do condense water on the PCB,
remove power from the TV, apply a little heat, and wait until the
water evaporates before trying again.
You missed a golden opportunity when you discovered that:
>I measured 267V between BD9101 and J858, so that's the
>benchmark in case it dies again.
The LED's are connected in series. That means you should see a
>benchmark in case it dies again.
voltage equal to 267V divided by the number of strips, across each
strip.
<https://www.shopjimmy.com/samsung-bn96-34251a-bn96-34252a-led-backlight-strips-14/#mz-expanded-view-1444464375404>
Assuming they're all in series, that would be:
267 / 14 = 19V
Walk your DVM across each strip and see which one has the full 267V
across it. That's the defective (open) LED strip.
Jeff Liebermann
Jul 23, 2022, 6:32:00 PM7/23/22
to
On Sat, 23 Jul 2022 14:53:50 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:
Never mind. It looks like you will need to disassemble the LCD panel
in order to obtain access to the LED connections. Once everything is
disassembled, you might as well replace all the LED strips instead of
trying to find the one with an intermittent connection.
I just watched the LED replacement video at:
<https://youtu.be/y5d_JkOEBSg>
I can't deduce which LED strip is bad, but my guess(tm) is it's one of
the two pin connectors on the LED strips. See video starting at:
<https://youtu.be/y5d_JkOEBSg?t=472>
My free advice is to put the TV back together and hope it continues to
function normally. This doesn't appear to be a paying repair, so you
might be able to convince the owner to do it this way which minimizes
the risk of breaking the panel. After all, the previous repair lasted
3 years. If it fails in the future, order the parts and follow the
video. I couldn't (and wouldn't) do that to a paying customer who
expects a repair and a warranty on the labor.
BTW, you were right about your suspicion that the problem wasn't the
main board. The repair shop probably had the intermittent back
lighting magically fix itself, and just added the board replacement to
the invoice to make it look like they actually did something useful.
wrote:
in order to obtain access to the LED connections. Once everything is
disassembled, you might as well replace all the LED strips instead of
trying to find the one with an intermittent connection.
I just watched the LED replacement video at:
<https://youtu.be/y5d_JkOEBSg>
I can't deduce which LED strip is bad, but my guess(tm) is it's one of
the two pin connectors on the LED strips. See video starting at:
<https://youtu.be/y5d_JkOEBSg?t=472>
My free advice is to put the TV back together and hope it continues to
function normally. This doesn't appear to be a paying repair, so you
might be able to convince the owner to do it this way which minimizes
the risk of breaking the panel. After all, the previous repair lasted
3 years. If it fails in the future, order the parts and follow the
video. I couldn't (and wouldn't) do that to a paying customer who
expects a repair and a warranty on the labor.
BTW, you were right about your suspicion that the problem wasn't the
main board. The repair shop probably had the intermittent back
lighting magically fix itself, and just added the board replacement to
the invoice to make it look like they actually did something useful.
Peabody
Jul 24, 2022, 10:06:21 AM7/24/22
to
Jeff Liebermann says...
> The LED's are connected in series. That means you
> should see a voltage equal to 267V divided by the number
> of strips, across each strip. <https://www.shopjimmy.com
> /samsung-bn96-34251a-bn96-34252a-led-backlight-strips-
> 14/#mz-expanded-view-1444464375404> Assuming they're all
> in series, that would be: 267 / 14 = 19V Walk your DVM
> across each strip and see which one has the full 267V
> across it. That's the defective (open) LED strip.
> The LED's are connected in series. That means you
> should see a voltage equal to 267V divided by the number
> of strips, across each strip.
<https://www.shopjimmy.com/samsung-bn96-34251a-bn96-34252a-led-backlight-
strips-14/#mz-expanded-view-1444464375404>
> Assuming they're all in series, that would be:
> 267 / 14 = 19V
> Walk your DVM across each strip and see which one has
> the full 267V across it. That's the defective (open)
> LED strip.
As you said later, I can't get to them without taking
everything apart. But I'm confused about what the LED
circuit is:
First, the ShopJimmy LED package has 7 strips of 8 LEDs,
plus 7 strips of 5 LEDs. Is this an all-Samsung LED package
so you might not need to use all of them, or are there 91
LEDs in my TV? If not 91, how many?
Second, there appear to be three chains of LEDs in the TV,
connected in series, but the interconnects between the three
chains are on the power supply board via the connector:
Voltage vs Chassis Ground
Connector Pin Black Mixed Light
1+ (also BD9101) 240 283 284
1-, 2+ 153 168 182
2-, 3+ 96 90 113
3- (also J858) 42 15 45
I got these readings by connecting my computer via HDMI.
"Black" means a black screen. Light is an editor that's
almost all whaite space, and Mixed is a video of Glenn
Gould playing the piano. When in Black, the LEDs are dark -
no light visible coming through the chassis. So the main
board clearly has some way of modifying the backlight
brightness.
But while Black looks like the LEDs are off, there obviously
must be some current getting through.
So how many LEDs are in each of the three circuits? And do
these numbers tell me anything about what might be wrong?
The screen looks completely normal on the front, so I assume
the readings above are normal.
I've decided that I'm not going to replace the LED strips
unless I can prove that's the problem. I don't want to go
through all that, and spend the money, only to end up with
it still not working. I think proof would be high voltage
applied to the LED string, but no light. And I can't get
that unless it goes back to not working. Short of that, I
can check the electrolytics on the power board, and replace
any that look bad. And maybe try the coolant thing. However,
the owner confirmed that once the backlight comes on, it never
goes off on its own. It continues to work until they turn off
the TV. So I would have to apply coolant while it's off, and
hope it won't turn on.
I have not checked to see if there's any PWM going on in the
LED supply. But I'm not sure it matters.
> The LED's are connected in series. That means you
> should see a voltage equal to 267V divided by the number
> of strips, across each strip. <https://www.shopjimmy.com
> /samsung-bn96-34251a-bn96-34252a-led-backlight-strips-
> 14/#mz-expanded-view-1444464375404> Assuming they're all
> in series, that would be: 267 / 14 = 19V Walk your DVM
> across each strip and see which one has the full 267V
> across it. That's the defective (open) LED strip.
> The LED's are connected in series. That means you
> should see a voltage equal to 267V divided by the number
> of strips, across each strip.
<https://www.shopjimmy.com/samsung-bn96-34251a-bn96-34252a-led-backlight-
strips-14/#mz-expanded-view-1444464375404>
> Assuming they're all in series, that would be:
> 267 / 14 = 19V
> Walk your DVM across each strip and see which one has
> the full 267V across it. That's the defective (open)
> LED strip.
everything apart. But I'm confused about what the LED
circuit is:
First, the ShopJimmy LED package has 7 strips of 8 LEDs,
plus 7 strips of 5 LEDs. Is this an all-Samsung LED package
so you might not need to use all of them, or are there 91
LEDs in my TV? If not 91, how many?
Second, there appear to be three chains of LEDs in the TV,
connected in series, but the interconnects between the three
chains are on the power supply board via the connector:
Voltage vs Chassis Ground
Connector Pin Black Mixed Light
1+ (also BD9101) 240 283 284
1-, 2+ 153 168 182
2-, 3+ 96 90 113
3- (also J858) 42 15 45
I got these readings by connecting my computer via HDMI.
"Black" means a black screen. Light is an editor that's
almost all whaite space, and Mixed is a video of Glenn
Gould playing the piano. When in Black, the LEDs are dark -
no light visible coming through the chassis. So the main
board clearly has some way of modifying the backlight
brightness.
But while Black looks like the LEDs are off, there obviously
must be some current getting through.
So how many LEDs are in each of the three circuits? And do
these numbers tell me anything about what might be wrong?
The screen looks completely normal on the front, so I assume
the readings above are normal.
I've decided that I'm not going to replace the LED strips
unless I can prove that's the problem. I don't want to go
through all that, and spend the money, only to end up with
it still not working. I think proof would be high voltage
applied to the LED string, but no light. And I can't get
that unless it goes back to not working. Short of that, I
can check the electrolytics on the power board, and replace
any that look bad. And maybe try the coolant thing. However,
the owner confirmed that once the backlight comes on, it never
goes off on its own. It continues to work until they turn off
the TV. So I would have to apply coolant while it's off, and
hope it won't turn on.
I have not checked to see if there's any PWM going on in the
LED supply. But I'm not sure it matters.
Chris K-Man
Jul 24, 2022, 5:57:31 PM7/24/22
to
On Thursday, July 21, 2022 at 12:01:15 AM UTC-4, Peabody wrote:
> Friends of mine have a Samsung 55" 4K TV, model UN55HU6840 (about 2014).
> They say they can hear audio, but the screen is black. I'd like to take a
> shot at fixing it for them since they don't really have the money to buy
> a new one. The encouraging thing is that until recently this has been an
> intermittent problem that's just gradually gotten worse, and now is
> permanent. But I'm encouraged to think it's not burned out LEDs, else it
> would never have been intermittent.
>
> I just told you everything I know about repairing TVs, but am generally
> experienced in electronics as a hobbyist. Based on some Youtube videos
> it seems I should take off the back cover and check all the connections.
> Then I would go to the power board and check the voltages on the lines
> going to the backlight LEDs, and if low, start checking diodes and
> electrolytics, and of course look for bad solder joints.
>
> Does this sound like a reasonable approach? Is there a typical cause of
> this symptom?
>
> Friends of mine have a Samsung 55" 4K TV, model UN55HU6840 (about 2014).
> They say they can hear audio, but the screen is black. I'd like to take a
> shot at fixing it for them since they don't really have the money to buy
> a new one. The encouraging thing is that until recently this has been an
> intermittent problem that's just gradually gotten worse, and now is
> permanent. But I'm encouraged to think it's not burned out LEDs, else it
> would never have been intermittent.
>
> I just told you everything I know about repairing TVs, but am generally
> experienced in electronics as a hobbyist. Based on some Youtube videos
> it seems I should take off the back cover and check all the connections.
> Then I would go to the power board and check the voltages on the lines
> going to the backlight LEDs, and if low, start checking diodes and
> electrolytics, and of course look for bad solder joints.
>
> Does this sound like a reasonable approach? Is there a typical cause of
> this symptom?
>
> I've had no luck finding a schematic. Does anyone know where I would
> find that?
>
> find that?
>
> Well, any guidance would be appreciated.
____________________
And once it is repaired, do not operate the set with the backlight set any higher than 12(I believe Samsung backlight
scale is 1-20). Use a higher Brightness(black level) setting to see detail in darker parts of the image
Peabody
Jul 25, 2022, 12:11:46 PM7/25/22
to
Ok I think I've figured it out. One strip of LEDs across
the panel consists of one 8-LED section plus one 5-LED
section. So 7 strips times 13 LEDs is 91 LEDs. The
voltages show there are one three-strip (39-LED) and two
two-strip (26-LED) lines that are individually wired back to
the power board, but are simply jumpered together there.
This confirms what you guys said - in effect all the LEDs
are in series, so any problem with one LED, or one
connection, and they all go out.
I think this is the most relevant video on LED replacements.
It's not exactly the same model, but very similar:
https://www.youtube.com/watch?v=oI52B4ba2Dg
It doesn't look too bad, except I don't have the suction
cups. But as of this morning, ShopJimmy is out of stock on
these, with no indication of a restock date. I can get them
on Amazon for $100, or I can get knockoffs on Ebay for as
little as $40. I don't know if the Ebay Chinese ones are
any good. And I don't know if the Amazons are different
from the Chinese ones on Ebay.
https://www.ebay.com/itm/125141436851
I did try disconnecting the main board, and the LEDs did
indeed light up fully, with about 281V across the LEDs. But
unfortunately, it's still working, so there's still no way
to tell where the problem is. It could be the main board
(unlikely, but still possible), the power board, or the
LEDs. And I just can't narrow it down unless it goes into
failure mode again.
So I'm going to continue testing it for a couple days, but
if it doesn't fail again, I'll give it back to the owner.
After all, with all the messing around I did, I may have
fixed whatever was wrong, and it may go another five years.
I really appreciate everyone's help with this. I just wish
we had reached more definitive result.
the panel consists of one 8-LED section plus one 5-LED
section. So 7 strips times 13 LEDs is 91 LEDs. The
voltages show there are one three-strip (39-LED) and two
two-strip (26-LED) lines that are individually wired back to
the power board, but are simply jumpered together there.
This confirms what you guys said - in effect all the LEDs
are in series, so any problem with one LED, or one
connection, and they all go out.
I think this is the most relevant video on LED replacements.
It's not exactly the same model, but very similar:
https://www.youtube.com/watch?v=oI52B4ba2Dg
It doesn't look too bad, except I don't have the suction
cups. But as of this morning, ShopJimmy is out of stock on
these, with no indication of a restock date. I can get them
on Amazon for $100, or I can get knockoffs on Ebay for as
little as $40. I don't know if the Ebay Chinese ones are
any good. And I don't know if the Amazons are different
from the Chinese ones on Ebay.
https://www.ebay.com/itm/125141436851
I did try disconnecting the main board, and the LEDs did
indeed light up fully, with about 281V across the LEDs. But
unfortunately, it's still working, so there's still no way
to tell where the problem is. It could be the main board
(unlikely, but still possible), the power board, or the
LEDs. And I just can't narrow it down unless it goes into
failure mode again.
So I'm going to continue testing it for a couple days, but
if it doesn't fail again, I'll give it back to the owner.
After all, with all the messing around I did, I may have
fixed whatever was wrong, and it may go another five years.
I really appreciate everyone's help with this. I just wish
we had reached more definitive result.
ohg...@gmail.com
Jul 25, 2022, 12:20:39 PM7/25/22
to
ohg...@gmail.com
Jul 25, 2022, 12:29:34 PM7/25/22
to
On Monday, July 25, 2022 at 12:11:46 PM UTC-4, Peabody wrote:
>
>
> I did try disconnecting the main board, and the LEDs did
> indeed light up fully, with about 281V across the LEDs. But
> unfortunately, it's still working,
Don't run it long with the main disconnected when testing - it will run the LEDs at higher current than full backlight adjustment will even drive them. Good for a quick test but don't leave it running that way.
> indeed light up fully, with about 281V across the LEDs. But
> unfortunately, it's still working,
Put the TV on a static input (DVD in pause) and watch that voltage across the LED array. If it drifts more than a couple of tenths either way, either an LED is starting to break down or there's a resistive contact in the interconnects. Sometimes one or both will settle down for a while before acting up again.
There is another possibility however. Most Samsung LEDs are built with a zener inside each die. Ordinarily, the zener does nothing but if the LED fails open, the entire voltage of the array will appear across the zener causing it to conduct and (hopefully) short hard effectively jumping out the bad LED. If it does, the problem will fix itself until another wayward LED crops up or if an interconnect gets resistive.
Peabody
Jul 25, 2022, 1:41:31 PM7/25/22
to
ohg...@gmail.com says...
> There is another possibility however. Most Samsung LEDs
> are built with a zener inside each die. Ordinarily, the
> zener does nothing but if the LED fails open, the entire
> voltage of the array will appear across the zener
> causing it to conduct and (hopefully) short hard
> effectively jumping out the bad LED. If it does, the
> problem will fix itself until another wayward LED crops
> up or if an interconnect gets resistive.
If I connect my computer to the TV via HDMI, and display a
competely white (all FFs) BMP image full screen, would I be
able to detect an LED that's not lighting up? Would there
be a dark area on the screen, or is the failure of one LED
not enough to cause a detectable darker area on the screen?
When I try this, I don't see anything unusual. The display
is a little darker in the corners, but I think that's normal.
> There is another possibility however. Most Samsung LEDs
> are built with a zener inside each die. Ordinarily, the
> zener does nothing but if the LED fails open, the entire
> voltage of the array will appear across the zener
> causing it to conduct and (hopefully) short hard
> effectively jumping out the bad LED. If it does, the
> problem will fix itself until another wayward LED crops
> up or if an interconnect gets resistive.
competely white (all FFs) BMP image full screen, would I be
able to detect an LED that's not lighting up? Would there
be a dark area on the screen, or is the failure of one LED
not enough to cause a detectable darker area on the screen?
When I try this, I don't see anything unusual. The display
is a little darker in the corners, but I think that's normal.
ohg...@gmail.com
Jul 25, 2022, 1:44:41 PM7/25/22
to
ohg...@gmail.com
Jul 25, 2022, 1:50:23 PM7/25/22
to
On Monday, July 25, 2022 at 1:41:31 PM UTC-4, Peabody wrote:
> ohg...@gmail.com says...
> > There is another possibility however. Most Samsung LEDs
> > are built with a zener inside each die. Ordinarily, the
> > zener does nothing but if the LED fails open, the entire
> > voltage of the array will appear across the zener
> > causing it to conduct and (hopefully) short hard
> > effectively jumping out the bad LED. If it does, the
> > problem will fix itself until another wayward LED crops
> > up or if an interconnect gets resistive.
> If I connect my computer to the TV via HDMI, and display a
> competely white (all FFs) BMP image full screen, would I be
> able to detect an LED that's not lighting up?
Probably, but Samsung does a good job with their lens design on their back lit models. Think about it - there is a fair amount of dead space between LEDs as they're laid out and generally you don't see the individual LED illumination even on a plain white display. There will be *some* unevenness if an LED goes out, but it's generally not dramatic, but your all white bit map pattern might show it. Try different brightness settings when you're looking at it. I've also seen some older Samsungs with half the LEDs shorted and the customers didn't complain at all about the picture until one opened and shut the array down.
> > There is another possibility however. Most Samsung LEDs
> > are built with a zener inside each die. Ordinarily, the
> > zener does nothing but if the LED fails open, the entire
> > voltage of the array will appear across the zener
> > causing it to conduct and (hopefully) short hard
> > effectively jumping out the bad LED. If it does, the
> > problem will fix itself until another wayward LED crops
> > up or if an interconnect gets resistive.
> If I connect my computer to the TV via HDMI, and display a
> competely white (all FFs) BMP image full screen, would I be
> able to detect an LED that's not lighting up?
John Robertson
Jul 25, 2022, 2:07:23 PM7/25/22
to
shorted primary side of the switching supply. Hard short at the output
of the first bridge rectifier. Noticed a few small value caps that are
slightly bulging - is there anything else to check/replace on this
series other than the shorted MOSFets and suspect caps?
I'm going to suggest he add a small fan to the backside of the TV to get
longer life...
Thanks!
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
#7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
ohg...@gmail.com
Jul 25, 2022, 3:15:36 PM7/25/22
to
On Monday, July 25, 2022 at 2:07:23 PM UTC-4, John Robertson wrote:
> >
> One of my employees brought in a Samsung 55" UN55JU7100 that has a
> shorted primary side of the switching supply. Hard short at the output
> of the first bridge rectifier. Noticed a few small value caps that are
> slightly bulging - is there anything else to check/replace on this
> series other than the shorted MOSFets and suspect caps?
>
> I'm going to suggest he add a small fan to the backside of the TV to get
> longer life...
>
No, you'll be good to go. Just change the shorted MosFets and the caps, and it should fly. If you're very unlucky, the gate driver IC might have failed but usually the fuse will blow quick enough. If the customer changed or jumped the fuse, the gate driver IC will most likely fail on AC plug in.
> >
> One of my employees brought in a Samsung 55" UN55JU7100 that has a
> shorted primary side of the switching supply. Hard short at the output
> of the first bridge rectifier. Noticed a few small value caps that are
> slightly bulging - is there anything else to check/replace on this
> series other than the shorted MOSFets and suspect caps?
>
> I'm going to suggest he add a small fan to the backside of the TV to get
> longer life...
>
You don't need a fan, but they way to extend the life of these is to lower the back light setting. Any TV I repair automatically gets a small mod to reduce the back light current regardless of where the customer sets the adjustment in the picture menu. Most LED TVs use a fixed LED voltage on the high side of the array and a MosFet on the low side which controls the current. I raise the value of the MosFet Source resistor (senses current) to fool the feedback.
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