Just finished 2 17" LG monitors I rescued from being recycled at the office.
# 1 LG 1752
Has a sticky note on it that says "Dead"
I plug it in, works fine...
Disassemble, find Samxon GF caps, all look really good.
I do a full re-cap minus the big one, and re-solder some questionable joints.
All the Samxons test fine ESR-wise, a few are a bit low in uf, but within spec.
Put it mostly back together to test, and....
It's dead Jim! Nice, I usually try NOT to make things worse when I repair... Hmm. What did I do? solder bridge? backwards cap?
I examine thoroughly, can't see anything obvious.
re-test, nothing. No 5v no 12v, 160somthing on the big cap.
re-re-examine, no long leads shorting to ground, no solder puke from my vacuum tool. I spray with flux remover, brush clean and examine under magnification.
I questionable solder joint I missed. re-solder, test. Still dead.
About to put it down and get a beer, when I decide to look closely at the pile of Samxon caps on my bench. Wait a sec! that little one is .47uf@50v NOT 47uf@50v. <slaps forehead> I bet it's the startup cap too.
I don't have any .47@50s, so I measure the Samxon, and put it back in.
Test. WHEW! Working great.
I re-assemble and start #2
#2 LG 1753, same as the 1752, 'cept for a black bezel, and the LED is in a different spot. Plug it in, dead.
Disassemble, looks just like the 1752, 'cept this one has one slightly bloated Samxon.
Re-cap all but the big one, and the .47uf
Partial re-assemble, and works like new.
Odd that the older higher mileage 1752 had perfect caps, and the newer had a bloated high esr 1000 @ 16....
# 1 LG 1752
Has a sticky note on it that says "Dead"
I plug it in, works fine...
Disassemble, find Samxon GF caps, all look really good.
I do a full re-cap minus the big one, and re-solder some questionable joints.
All the Samxons test fine ESR-wise, a few are a bit low in uf, but within spec.
Put it mostly back together to test, and....
It's dead Jim! Nice, I usually try NOT to make things worse when I repair... Hmm. What did I do? solder bridge? backwards cap?
I examine thoroughly, can't see anything obvious.
re-test, nothing. No 5v no 12v, 160somthing on the big cap.
re-re-examine, no long leads shorting to ground, no solder puke from my vacuum tool. I spray with flux remover, brush clean and examine under magnification.
I questionable solder joint I missed. re-solder, test. Still dead.
About to put it down and get a beer, when I decide to look closely at the pile of Samxon caps on my bench. Wait a sec! that little one is .47uf@50v NOT 47uf@50v. <slaps forehead> I bet it's the startup cap too.
I don't have any .47@50s, so I measure the Samxon, and put it back in.
Test. WHEW! Working great.
I re-assemble and start #2
#2 LG 1753, same as the 1752, 'cept for a black bezel, and the LED is in a different spot. Plug it in, dead.
Disassemble, looks just like the 1752, 'cept this one has one slightly bloated Samxon.
Re-cap all but the big one, and the .47uf
Partial re-assemble, and works like new.
Odd that the older higher mileage 1752 had perfect caps, and the newer had a bloated high esr 1000 @ 16....
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