Samsung TV
Baron
TV Model LE37R87BDX.
Google gets lots of hits, but they are all dead ends in one way or
another.
Mine has just decided to switch itself off and sulk ! :-(
Thanks.
--
Best Regards:
Baron.
Arfa Daily
"Baron" <baron....@linuxmaniac.nospam.net> wrote in message
news:ig060g$9f6$1...@news.eternal-september.org...
Hi Baron
I don't have access to service info for that tv unfortunately, but if it's
like most LCDs, the dead set symptom is mostly down to psu trouble, and most
are not that difficult to sort without schematics. Often, it's just caps, as
I'm sure you've seen mentioned on here many times. You will often find the
voltages marked on the psu boards. By connectors is a good place to look.
Typically, there will be a standby supply of 3v3 and/or 5v. The main
switched rails are usually some or all of 3v3, 5v, 12v, 24v for the
backlight supply, and 33v for the tuner. Occasionally, the odd negative
rail.
If it does come down to psu, and you can't fix it, a replacement board is
available here
http://www.lcdpartsforyou.com/apps/webstore/products/show/940845
for a very reasonable price. In the meantime, I will ask my mate who does a
great deal of LCD tv repairs, if there is anything common on that model that
he knows of.
Arfa
hrho...@att.net
Have you checked SAM"S PHotofacts?
Arfa Daily
"Baron" <baron....@linuxmaniac.nospam.net> wrote in message
news:ig060g$9f6$1...@news.eternal-september.org...
OK. Had a word with my mate, and he says that it's pretty much always power
supply caps on that model. He reckons that there's about four of 'em which
will all have blown their tops, and he says it's obvious as soon as you take
the back off. He also said that if it has been a bit iffy at starting up for
a while, then sometimes, it also twats the EEPROM, so if there are any
further issues after replacing the caps, that will be the cause.
Good luck with it ! d;~}
Arfa
Baron
Hi Arfa,
Thanks. I did pull the back off today and as you say the voltages are
marked on the PSU PCB. All the ones that I could identify I probed
without finding one that wasn't correct.
I did note that the red led in the middle of the power button seems to
have a weird flash sequence, so I suspect that its some kind of fault
code, a bit like the BIOS beep codes.
Once again I'm grateful for any help I can get.
Many Thanks.
--
Best Regards:
Baron.
Baron
Baron
There are no obvious signs of any damage. No smells, no burning, no
noise, not that I would have heard it over the program sound. Though
bad caps was the first thing that I suspected.
I'm going to take it into work with me tomorrow and have a look at the
power rails with a scope.
I'll report back. Take care.
Thanks again.
--
Best Regards:
Baron.
Baron
Hi Arfa,
Well I scoped the power rails without finding anything I could report as
useful. The ripple that I did find was around 120mv and that was on
the 33v rail. Some really odd waveforms on other pins, but meaningless
without knowing what they were for. I did note that the heatsink for
the CPU got moderately hot over the ten/fifteen minutes that I was
checking voltage lines.
Stuck for the moment. :-(
Thanks:
--
Best Regards:
Baron.
Arfa Daily
>>
>
> Hi Arfa,
> Well I scoped the power rails without finding anything I could report as
> useful. The ripple that I did find was around 120mv and that was on
> the 33v rail. Some really odd waveforms on other pins, but meaningless
> without knowing what they were for. I did note that the heatsink for
> the CPU got moderately hot over the ten/fifteen minutes that I was
> checking voltage lines.
>
> Stuck for the moment. :-(
> Thanks:
>
> --
> Best Regards:
> Baron.
I'll be in his shop tomorrow. If I remember, I'll ask if he's had anything
else on those. Was there any prior symptoms ? Did it fail whilst on, or fail
to come out of standby. What exactly is the standby LED doing ? If it is
pulsing, have you tried unplugging the backlight inverter ?
Arfa
Baron
>
> I'll be in his shop tomorrow. If I remember, I'll ask if he's had
> anything else on those. Was there any prior symptoms ? Did it fail
> whilst on, or fail to come out of standby. What exactly is the standby
> LED doing ? If it is pulsing, have you tried unplugging the backlight
> inverter ?
>
> Arfa
Hi Arfa,
It was running just fine, then without any warning the display went off
and the little red standby LED in the middle of the button started
flashing. 3short, delay, 1long, off, delay then the sequence starts
again.
No I haven't disconnected the backlight panel. There seems to be 6 or 8
inverters on a separate panel running vertically up the left side,
viewed from the rear. There is a single multiway cable connecting the
inverter panel to the PSU board. The backlight panel is under a metal
screen, making it hard to see underneath without removing fairly
substantial metalwork.
Arfa Daily
"Baron" <baron....@linuxmaniac.nospam.net> wrote in message
news:ig70en$n13$1...@news.eternal-september.org...
It's only the plug to the inverter board that you need to remove. From the
described symptoms, I doubt that the problem is going to be that, but it is
common for backlight inverters to fail on all makes of LCD TV, and the
excess load then placed on the PSU's 24v rail can cause some odd and bizarre
startup problems, depending on how and where the supply monitors it's output
voltages and the current draws on the various rails. Normally, although the
connector to the inverter board has a lot of wires, most of them are just
paralleled-up +24v and gnd. There is often a control wire also.
I was unable to check further with my mate today, as he is off with man-flu.
The other guy in the shop is more computers than TV, so doesn't know a lot
about TV faults.
Arfa
Baron
>
> "Baron" <baron....@linuxmaniac.nospam.net> wrote in message
> news:ig70en$n13$1...@news.eternal-september.org...
>> Arfa Daily Inscribed thus:
>>>
>>> I'll be in his shop tomorrow. If I remember, I'll ask if he's had
>>> anything else on those. Was there any prior symptoms ? Did it fail
>>> whilst on, or fail to come out of standby. What exactly is the
>>> standby LED doing ? If it is pulsing, have you tried unplugging the
>>> backlight inverter ?
>>>
>>> Arfa
>>
>> Hi Arfa,
>> It was running just fine, then without any warning the display went
>> off and the little red standby LED in the middle of the button
>> started flashing. 3short, delay, 1long, off, delay then the sequence
>> starts again.
>>
>> No I haven't disconnected the backlight panel. There seems to be 6
>> or 8 inverters on a separate panel running vertically up the left
>> side, viewed from the rear. There is a single multiway cable
>> connecting the inverter panel to the PSU board. The backlight panel
>> is under a metal screen, making it hard to see underneath without
>> removing fairly substantial metalwork.
>>
>> Thanks:
>> --
>> Best Regards:
>> Baron.
Hi Arfa,
>
> It's only the plug to the inverter board that you need to remove. From
> the described symptoms, I doubt that the problem is going to be that,
> but it is common for backlight inverters to fail on all makes of LCD
> TV, and the excess load then placed on the PSU's 24v rail can cause
> some odd and bizarre startup problems, depending on how and where the
> supply monitors it's output voltages and the current draws on the
> various rails. Normally, although the connector to the inverter board
> has a lot of wires, most of them are just paralleled-up +24v and gnd.
> There is often a control wire also.
Yes I did disconnect the cable from the main board to the inverter board
where it connects to the PSU board. It made no difference ! :-(
I've a sneaky feeling that the flashing sequence of the power LED is
trying to tell me something, but I haven't been able to find out what.
> I was unable to check further with my mate today, as he is off with
> man-flu. The other guy in the shop is more computers than TV, so
> doesn't know a lot about TV faults.
> Arfa
I'm afraid thats the camp I'm in. 35+ years ago TV's were much more
understandable, read simple, to understand.
Your help is very much appreciated.
Thanks:
PS. At least the old 28" Bush and digibox still work... (*)
--
Best Regards:
Baron.