replacing smps component

fr...@notvalid.it

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Jan 17, 2011, 5:01:53 AM1/17/11

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Hi all,

I'm repairing an LCD computer monitor. The smps is faulty, found a couple
of bulging capacitors on the low voltage side, the AC fuse blown, a blown 22V
1W zener on the primary side, the main 100 uF 400V capacitor after the
rectifier on AC side open circuit, and an exploded FSDM0565R integrated
controller and driver (luckily the parts exploded away were readable).
Now, where I could find the FSDM part?
In your opinion is this worth trying to repair or it might have blown parts
like transformers (not something you can find on the market I mean)?
Thanks in advance and best regards

Frank IZ8DWF

Wild_Bill

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Jan 17, 2011, 8:19:10 AM1/17/11

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With that much damage obvious just by visual inspection, I'd suspect that
the other boards also have damaged components.

I might try to use some alternate power supplies to see if the monitor can
display an image before attempting to locate parts for the SMPS.. even if
the image might only be the OSD on-screen display stating "no input signal"
could be considered a good sign, indicating that the other boards might not
be damaged (a definite maybe).

Many LCDs only need a couple of voltages to operate.. some may be minus (-)
supplies, but other than correct polarity, fairly common voltages.

Even some batteries (in various numbers wired in series) may be adequate for
testing.

--
Cheers,
WB
.............

<fr...@notvalid.it> wrote in message
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Dave M

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Jan 17, 2011, 2:35:21 PM1/17/11

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Is the power supply integral to the monitor or is it an external table
mounted brick? If it's a brick, your best (and cheapest) sollution is to
fiind a suitable replacement.
If it's a brick, what is the output voltage and current (shown on the
label)?
--
David
dgminala at mediacombb dot net

Dave M

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Jan 17, 2011, 2:48:30 PM1/17/11

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Mouser (http://www.mouser.com/Search/Refine.aspx?Keyword=FSDM0565R),
Digikey
(http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=FSDM0565R&x=24&y=17)
and Newark
(http://www.newark.com/fairchild-semiconductor/fsdm0565rewdtu/dp/07P9256)
all list them as stocked item, but Mouser shows them on order. The others
show them as being in stock.

Arfa Daily

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Jan 17, 2011, 8:19:54 PM1/17/11

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<fr...@notvalid.it> wrote in message
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Long (and often bitter !) experience of repairing switchers for a living,
would cause me to say that with that sort of level of primary side failure,
successful - and reliable - repair, is unlikely to be practical.

Sorry :-(

Arfa

fr...@notvalid.it

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Jan 18, 2011, 6:48:19 AM1/18/11

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Wild_Bill <wb_wi...@xspamyahoo.com> wrote:
> With that much damage obvious just by visual inspection, I'd suspect that
> the other boards also have damaged components.
>
> I might try to use some alternate power supplies to see if the monitor can
> display an image before attempting to locate parts for the SMPS.. even if
> the image might only be the OSD on-screen display stating "no input signal"
> could be considered a good sign, indicating that the other boards might not
> be damaged (a definite maybe).
>
> Many LCDs only need a couple of voltages to operate.. some may be minus (-)
> supplies, but other than correct polarity, fairly common voltages.

I just did it, the LCD requires only +5 and +12 and the HV for backlight.
Unfortunately the inverters for the backlight are on the smps board so the
screen remained dark but I coul see some activity in the dark.
Hard to tell if everything is ok, but there's some life.
I think I'll order a complete smps replacement board from china (which will
last a couple of years again).

Thanks

Frank IZ8DWF