LG42G1A_YSUS EAX52396901 Troubleshooting

[barkster]

I have a LG 42GI1A-YSUS board that I can't find what is wrong with it. It is getting 190v in but the voltage our readings are bad and I've been checking caps, regulators and diodes and can't find the bad parts. Can someone point me in the right direction. I've been having bad luck on repairs lately. I've repaired my first 4-5 tv's pretty fast and now I have 5 more that have been sitting in my garage and can't find the issues. These are turning out to be a bigger learning experience for me. Here are the input/output voltages I'm reading with buffer board disconnected. Thanks

VS= 190v
Vz+ 80.9
VZ- 0
Vy+ 3.2
Vy- 2.2
Vsc+ 4.05
Vsc- 2.1

[Alastair E]

Re: LG42G1A_YSUS EAX52396901 Troubleshooting

How are you measuring the -Vy and VSC...?

There should be only one voltage for each--Not two!

--I'm guessing you're measuring the test-points to chassis instead of the Correct way, as in meter to plus/minus of the -Vy/VSC...

[barkster]

Re: LG42G1A_YSUS EAX52396901 Troubleshooting

You are correct I was measuring to the chasis. There are two pads one labelled + and one - for Vy and Vz but I must have made a mistake on VSC as I only see on in picture. Anyhow, I'll recheck voltages the proper way tonight

[barkster]

Re: LG42G1A_YSUS EAX52396901 Troubleshooting

Ok, Vsc and Vy start at 180v then slowly drop to 1v and the tv stays on the whole time. Vz stays at a stable 80v, not sure what it is supposed to be. Sounds like a bad cap but I've desoldered and tested almost all of them. Any ideas?