Hi all. First of all, thanks for this awesome resource. It's a true asset to our internet community.
I have a 23" Samsung LN2353H (supply BN44-00158A) that died one night and would not turn back on. I tried it next day, and it turned on...but only stayed on for a little bit and after that, would only have the blue stby light flash momentarily after plugging in...and do that in a loop every few seconds. Would not power on. I could also hear a high pitch whine coming from the power supply board after the standby light in front flashed back off.
After much digging around the net, I ended up here where I was able to find a schematic and lots of great info.
Looking at the board, I was drawn to RM814, which had the discolored glue that looked like it had gotten a little cooked (I've read the glue can get conductive when old?). RM801 fusible resistor was blown w/ burn mark on side. Started testing what components I could on the board and found issues with:
RM801 (.22 Ohm 1W Fusible resistor) open
RM814 (3.3K resistor) bad - showing flucting resistance in MOhm range (tested out of board)
DM804 (D1NS4 Diode) shorted (tested out of the board)
ICM801S (F9222L IC) had both Q1 and Q2 source-drain shorts (Pins 4, 19, & 23, I believe it was...again, tested out of the board)
Couldn't really find anything else obviously bad, but have only ability to test basic components using DMM...nothing to test cap's ESR or anything.
After a couple purchases on Ebay (and some scavenging of an old tube TV), I was able to solder in the 4 replacement parts. Holding breath and plugging in....it powered up! I kept it on for a day or so and have powered off / on several times.
Now...the big question...I'm wondering if I've addressed the root of the issue, or just repaired the casualties from the real culprit and could have similar failure soon. Anything else I should look at here before I declare victory?
Thanks!
Mike
I have a 23" Samsung LN2353H (supply BN44-00158A) that died one night and would not turn back on. I tried it next day, and it turned on...but only stayed on for a little bit and after that, would only have the blue stby light flash momentarily after plugging in...and do that in a loop every few seconds. Would not power on. I could also hear a high pitch whine coming from the power supply board after the standby light in front flashed back off.
After much digging around the net, I ended up here where I was able to find a schematic and lots of great info.
Looking at the board, I was drawn to RM814, which had the discolored glue that looked like it had gotten a little cooked (I've read the glue can get conductive when old?). RM801 fusible resistor was blown w/ burn mark on side. Started testing what components I could on the board and found issues with:
RM801 (.22 Ohm 1W Fusible resistor) open
RM814 (3.3K resistor) bad - showing flucting resistance in MOhm range (tested out of board)
DM804 (D1NS4 Diode) shorted (tested out of the board)
ICM801S (F9222L IC) had both Q1 and Q2 source-drain shorts (Pins 4, 19, & 23, I believe it was...again, tested out of the board)
Couldn't really find anything else obviously bad, but have only ability to test basic components using DMM...nothing to test cap's ESR or anything.
After a couple purchases on Ebay (and some scavenging of an old tube TV), I was able to solder in the 4 replacement parts. Holding breath and plugging in....it powered up! I kept it on for a day or so and have powered off / on several times.
Now...the big question...I'm wondering if I've addressed the root of the issue, or just repaired the casualties from the real culprit and could have similar failure soon. Anything else I should look at here before I declare victory?
Thanks!
Mike
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