TH-P50G15A - 6 Blinks- Bad TNPA4782

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Well going through all the IGBTs again I just found Q660 is short... I didn't replace this one yet since it wasn't shorted the first few times I went over it.

I found easy to miss was it just c-e that was shorted?

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Have you replaced ic691 yet?

[Glitcher]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Ok I feel like im going crazy here... I remeasured Q660 and its not shorted now... I could of sworn I went over it twice and my meter beeped on continuity... I need a break =/

Also I haven't replace IC 691 yet

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Ok I feel like im going crazy here... I remeasured Q660 and its not shorted now... I could of sworn I went over it twice and my meter beeped on continuity... I need a break =/

Also I haven't replace IC 691 yet

yeah, I think so. I'm tired. IC691 may not be essential but I was thinking if q660 was short maybe. I have but only out of paranoia

So this is 6 blinking but nothing is blowing?

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

out of curiosity what resitance do you get across pins 10-20 on either ic561,562?

[Glitcher]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

I'm getting something like 169K on both those ICs pins 10-20. The thing is I plugged on the SC board with Sc50 shorted. It'll sound like the SC turns on for a second (starts buzzing) and then goes off and then it'll start blinking 6 times.

[tom66]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

You checked the MID voltage?

[Glitcher]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

It'll rise unstably up to about 45V at most and then drop at shutdown. This is across those blue poly caps in parallel I assume

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

out of curiosity what resitance do you get across pins 10-20 on either ic561,562?

just looking over the first board info I posted again.

D652 is that ok. Maybe throw a new IC691

My resistance is nothing like yours across 10-20 for those buffer ICs,ic561,562.
mine starts in the meg ohms decreasing slowly as it charges.


So I tried diode red on 10(gnd) = 0.484, Blk on 10(gnd) 0.968

[Glitcher]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

on diode mode im getting 0.535, and 1.105

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

on diode mode im getting 0.535, and 1.105

yep, so close enough, weird how our meters handle resistance differently in cct

[Glitcher]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Might just be my meter, I've always had trouble measuring resistances of anything in the 200K or Meg range. Never actually had to.

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Might just be my meter, I've always had trouble measuring resistances of anything in the 200K or Meg range. Never actually had to.

I don't where to steer you but this image I've done my best from memory what I replaced(believe) between the 2 boards I did. Not all of these were necessarily bad but most were

[Glitcher]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Yep I'm stumped... The only thing I noticed is the MID voltage is too low, peaking at around 45V. So I guess there has to be a problem with the FET and drivers? (IC521 I guess) Replaced some extra parts, and even some from your image but still no process... ugh I hate these boards -.-

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Yep I'm stumped... The only thing I noticed is the MID voltage is too low, peaking at around 45V. So I guess there has to be a problem with the FET and drivers? (IC521 I guess) Replaced some extra parts, and even some from your image but still no process... ugh I hate these boards -.-

Don't quit. There's only so many parts on the board. that's what i tell myself. All I know is I went from 145v to 45v and then fixed and that was with a blow up and fried buffers to boot.

[tom66]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

If its only going to 45V then the ckt is only being charged by the resistors to Vsus, I would check if the gate drivers are working (check their 5 & 16V supply)

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Are you able to put up some hi res shots of the board just so I can get an eyeball . thanks.

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

here's some diode readings

q451

g(red)
- E(blk)0.608,
- c(blk)1.041

g(blk)
- E(red)0.998,
- c(red) OL
E(red)
-C(blk) 0.47

E(blk)
- C(red) OL

Q441

g(red)
- E(blk)0.604,
- c(blk)charges and goes OL

g(blk)
- E(red)0.992,
- c(red) OL
E(red)
-C(blk) 1.94

E(blk)
- C(red) OL

[Glitcher]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Heres what I got on mine, seems pretty much the same.

q451

g(red)
- E(blk)0.654,
- c(blk)1.086

g(blk)
- E(red)1.065,
- c(red) OL
E(red)
-C(blk) 0.480

E(blk)
- C(red) OL

Q441

g(red)
- E(blk)0.661,
- c(blk) OL

g(blk)
- E(red)1.002,
- c(red) OL
E(red)
-C(blk) OL

E(blk)
- C(red) OL

[tw2005]

Re: TH-P50G15A - 6 Blinks- Bad TNPA4782

Heres what I got on mine, seems pretty much the same.

q451

g(red)
- E(blk)0.654,
- c(blk)1.086

g(blk)
- E(red)1.065,
- c(red) OL
E(red)
-C(blk) 0.480

E(blk)
- C(red) OL

Q441

g(red)
- E(blk)0.661,
- c(blk) OL

g(blk)
- E(red)1.002,
- c(red) OL
E(red)
-C(blk) OL

E(blk)
- C(red) OL

thanks, that's comparable.

Can you zoom in on D618 and illuminate?

R451,441, do they measure 5.6 ohms