Reporting back here chaps, issue fixed with replacing KSD526-Y with a BD243B NPN transistor, the PSU is back in business!
All your efforts are greatly appreciated, thank you once again!...
katinkapicinyke
Member
Last Activity: 05-05-2020, 10:06 PM
Joined: 03-28-2020
Location: London
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Re: problem with psu in Samsung 32"
Reporting back here chaps, issue fixed with replacing KSD526-Y with a BD243B NPN transistor, the PSU is back in business!
All your efforts are greatly appreciated, thank you once again!... -
Re: problem with psu in Samsung 32"
Thank you, yes, it is a metal backed To-220 as far as I can tell with no heatsink attached (KSD526-D)....Leave a comment:
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Re: problem with psu in Samsung 32"
Understood, thank you.
I've found a BD243B (NPN), would that be sufficient please?...Leave a comment:
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Re: problem with psu in Samsung 32"
One of those moments in life, when one only has a PNP in hand...
I found a TIP117 in my box of spares, could I just use that instead?...Leave a comment:
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Re: problem with psu in Samsung 32"
Thank you! Both de-soldered and checked, appeared to be working correctly....Leave a comment:
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Re: problem with psu in Samsung 32"
Thank you, I can see no short on CP811, CP805 (took me some time to find, little SMD bugger!), neither on CP805, CM807, nor on CM814.
The resistance between the two legs of CP811 is around 4.5K Ohm, give or take due to my meters tolerance....Last edited by katinkapicinyke; 03-30-2020, 02:33 PM.Leave a comment:
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Re: problem with psu in Samsung 32"
Thank you, just did that but appears to me the same outcome when measuring that elco capacitor....Leave a comment:
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Re: problem with psu in Samsung 32"
Also, thank you for your suggestion, I read the below but found them inconclusive in my case, almost appeared to me as SMPS fault on mine with no obvious symptom.
[url]https://www.badcaps.net/forum/showthread.php?t=34263&highlight=BN44-00214A[/url]
[url]https://www.badcaps.net/forum/showthread.php?t=68285&highlight=BN44-00214A[/url]Re: problem with psu in Samsung 32"<...y case, almost...Leave a comment:
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Re: problem with psu in Samsung 32"
One more thing please, with the mainboard, TCON and inverter connected I get 3.3V of SB constantly (would I be correct assuming logical HIGH sent back from the mainboard?) while powered up, it drops only for a mere second, so like goes to logical LOW (0V) and then back to 3.3V....Leave a comment:
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Re: problem with psu in Samsung 32"
First of all, thank you for all the above suggestions, much appreciated.
I've got a 1k resistor installed between SB and PS pins on CNM802, still no output on 12V/24V rails (I can measure 5.2V on the SB, also around 4V on PS once it is connected with the resistor).
With the above jumper in place, I'm only measuring about 324-330V on the big cap (CP803).
With the above jumper in place, I'm getting the following on QB802 (relative to HOT side GND of CP803):
Base:16.15V
Collector:23.9V...Leave a comment:
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Re: problem with psu in Samsung 32"
Hi All,
Sorry to resurrect such an ancient topic but dealing with an issue on the same model (Samsung LE32A457C1D) with the same PSU board. Did checks on the cold side of the PSU board, no sign of the 12V+ outputs (on turning on I get the same 5 red LED flashes and then nothing). That dreadful glue was all over QB802 and CP811, de-soldered QB802 (Fairchild D526-Y NPN transistor maybe?) and removed the glue, however the transistor test appears to be failing between B (with positive probe) towards E (negative probe) and C (negative probe)...Leave a comment:
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Re: New Members - please post your introductions here
Hi All,
I'm Si, 25 years old IT guy, who likes to spend time on electronics and other repairs.Leave a comment:
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