need help with caps on a plasma tv power supply board

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

hey im new to this meter give e a break lol, what should i have it set on can you tell me, replacing the battery now

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

ok fresh battery installed, now teach me please

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

got it! so now i just need insight on where to go from here,

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

so since i didnt get a response i started testing the transistors on a 20k ohm setting, and will the transistors ever have pins that will read short if theyre not shorted but its really the way they work? or is it just shorted and replace it?

[Agent24]

Re: need help with caps on a plasma tv power supply board

Your ohms range is too high, and maybe showing low resistances through paralleled components.

Use the lowest ohms range (since a short is by definition zero ohms) or, even better, use the diode test setting on the meter. It's the one with the diode symbol.

Make sure the TV is OFF when you do this.

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

Alright I'll test everything out when I get home in a bit

[tw2005]

Re: need help with caps on a plasma tv power supply board

Ok, so looks like we can't follow that procedure I had earlier as the side panel has the power switch and routes via the C boards so when the A31 white ribbon is removed there's no power on master switch.

i see p35 was still disconnected in your photo.

So hook everything up and disconnect Sn2 and SN20 ribbon, turn master switch on side panel on and do whatever you'd normally do to turn the TV on and see if it attempts to start but then turns off with a SOS blink.

[tw2005]

Re: need help with caps on a plasma tv power supply board

this may work, disconnect SN2,Sn20, ribbon c10/c20 may be tricky looks like it's right where the stand is, that should disable SOS8 return disconnect p35, ss11. Turn master switch on and power TV up . what i'm trying to do is to get the tv on with just the PSU and A board running without a blink, then you can confirm all the voltages like Vsus at P2, Vda at P35, P+15v,F15v, sOUND 15v, STB 5V at P6.

If we can get there then should just need a SN board or get yours repaired if Moduslink does them?

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

alright, i got back alittle late to mess around with it tonight so ill post tomorrow when i get up and around to it, thanks for the help tw2005

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

also what settings on my multimeter should i be using to test with? im assuming 20k ohm? or the AC current setting?

[Agent24]

Re: need help with caps on a plasma tv power supply board

also what settings on my multimeter should i be using to test with? im assuming 20k ohm? or the AC current setting?

It depends what you are testing for. What are you trying to measure?

I think you should have a serious read of something like this: https://learn.sparkfun.com/tutorials...e-a-multimeter

Or at the very least, watch this: https://www.youtube.com/watch?v=bF3OyQ3HwfU

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

this may work, disconnect SN2,Sn20, ribbon c10/c20 may be tricky looks like it's right where the stand is, that should disable SOS8 return disconnect p35, ss11. Turn master switch on and power TV up . what i'm trying to do is to get the tv on with just the PSU and A board running without a blink, then you can confirm all the voltages like Vsus at P2, Vda at P35, P+15v,F15v, sOUND 15v, STB 5V at P6.

If we can get there then should just need a SN board or get yours repaired if Moduslink does them?

ok so i did what you said, here and the tv comes on with the red LED (not sure what the tvs led should be doing if it were to be working 100%) the red light inside of a jack on the A board came on, and a few seconds later the TV shut down

i was able to test voltage on the DCV scale and as well as the AC scale heres what i found

P6 connection
15Vs on DCV= 1.54 on AC= when power button is pushed it spikes to 9.5 then down to 3.0 untill it shuts down

F15V on DCV= 15.75 on AC=34.2
F15V(#2) on DCV= 15.75 on AC= 34.2
STBY5V on DCV= 0.02 on AC= 00.0
VDA@ P35 on DCV= 0.04 on AC= 00.0
VSUS@ P2 on DCV= 0.00 on AC= 00.0

now with all connections made the tv tries to boot (NO VIDEO NO AUDIO) 10 sec later i hear a few relays click and the led goes out

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

also using the diode setting on my meter i tested the transistors on the SN board, and heres the ones i found that were bad/weak

D401, Q402, Q421, D421, Q422, C451, D481, D641, D642. these were tested while still on the SN board, i will be taking them off and testing them out of circuit to be sure, but are there any other known problems whith the SN board as far as having to replace bad or maybe going bad components?

[tom66]

Re: need help with caps on a plasma tv power supply board

Just to check, how did you determine those as bad?

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

I probed them on the diode setting, but I tested the diode by testing the leads one way then swapped. I youtubed how to do it not sure if I did it right. But I haven't taken them out of circuit yet haven't had time had to go buy a few things from radioshack

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

ok so ive removed all the bad (and a few good) transistors from the SN board circuit wise and tested them, the ones that i tested and thought they were bad tested bad still, and the good tested good, but how do i get these off the board without damaging it?

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

no one??

[Agent24]

Re: need help with caps on a plasma tv power supply board

Are they through-hole or surface-mount components you are trying to desolder?

[tw2005]

Re: need help with caps on a plasma tv power supply board

For $76, why not just get a pro to do it. A kit is going to be $20 -40 depending on what is actually blown. Then you're going to need a couple of soldering irons, solder maybe a flux pen etc.

Then there's the ? about experience plus starting with surface mounted parts is not something easy.

Depends if you just want to have a go for the experience or get this fixed economically.

i still have a suspicion about the PSU so you maybe up for one of those yet.

It's a shame you did not land here first because a SN replacement would have fixed this but not so sure now that you've played with the PSU.

there appears to be none of these boards around so at this point keeping that core in good condition so it can be repaired is worth considering.

http://www.moduslinkptstvboards.com/tnpa5349ad/

[9302z28ss]

Re: need help with caps on a plasma tv power supply board

how can i test the PSU and make sure i didnt mess anything up? im wanting to do this because i used to mess with electronics all the time and im currently wanting to make a profession out of it, and would like some practice on stuff i have or can find for free,

i need all the help i can get, so anyone that will help me out with getting this fixed id be greatfull