Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

[lookimback]

I've been working on this all day. Real pain in the @$$ because it seems to latch into protect mode and goes completely dead for about 5 minutes after you power it on. I did finally figure out that when the bad board was disconnected, you could hold the power switch for a minute and it will reset. If only I could get back those 3 or 4 wasted hours where i just unplugged it and waited...

Anyway, the SM leads one to suspect the A board with a 10 blink code, but it is apparently not always the case. I determined that with the SC disconnected, I'd momentarily get 200+ volts on P2, and I didn't have that with it connected. That was enough for me. So, after a couple of frustrating hours with a cheap solder sucker and some desoldering braid (I really need a vacuum desoldering gun) I have a long list of shorted components. The SC is a TNPA4844AD.

Q660 - RJK6026
Q661 - RJP6065
Q404 - 2PG011
Q422 - 30G123
Q423 - 30G123
Q424 - 30G123
D865 - 8688

And I suppose it would be wise to replace the 2 driver ICs as well.
IC501 - M8707FP
IC521 - M8707FP

I hope I didn't miss anything.

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I've been working on this all day. Real pain in the @$$ because it seems to latch into protect mode and goes completely dead for about 5 minutes after you power it on. I did finally figure out that when the bad board was disconnected, you could hold the power switch for a minute and it will reset. If only I could get back those 3 or 4 wasted hours where i just unplugged it and waited...

Anyway, the SM leads one to suspect the A board with a 10 blink code, but it is apparently not always the case. I determined that with the SC disconnected, I'd momentarily get 200+ volts on P2, and I didn't have that with it connected. That was enough for me. So, after a couple of frustrating hours with a cheap solder sucker and some desoldering braid (I really need a vacuum desoldering gun) I have a long list of shorted components. The SC is a TNPA4844AD.

Q660 - RJK6026
Q661 - RJP6065
Q404 - 2PG011
Q422 - 30G123
Q423 - 30G123
Q424 - 30G123
D865 - 8688

And I suppose it would be wise to replace the 2 driver ICs as well.
IC501 - M8707FP
IC521 - M8707FP

I hope I didn't miss anything.

check the p5v and p15v resistance, could be other smd stuff gone like transistors and maybe inverter ic . not sure if anyone has repaired one of these, maybe the 5081 sc thread may give ideas to check anything related to q661

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

Resistance to ground?

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

Resistance to ground?

yep

D865 is RF101L4S

This is a list from a 5 blink , bad SC tech bulletin in china

Q16661、Q16422、Q16423、Q16424

Q16404、Q16403、Q16402

Q16701、Q16702、D16865

IC16771、IC16464、IC16465、IC1677

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I'll get back on this later tonight, or over the weekend. Been a busy day. I appreciate the help though.

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I got around 4k ohms on SC20 between +15v and gnd. About 2m ohms between +5v and gnd. Of course, this is with the aforementioned components removed. I'll check all the smd transistors individually. Remaining diodes and FETs are ok.

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I got around 4k ohms on SC20 between +15v and gnd. About 2m ohms between +5v and gnd. Of course, this is with the aforementioned components removed. I'll check all the smd transistors individually. Remaining diodes and FETs are ok.

is the smd P fet ok?

I really don't know this board but there are a few hits searching TNPA4844. One bloke got it going then it popped again , see no resolution at the end of that post. You may be lucky and just the fets but it may be a good idea to use that 5 blink list since it also has some of thos schmitt inverter ic and small smd transitors which drive q661 in there.

these boards are I think are near impossible to find. i wonder what modus charges? But I guess you prefer the challenge

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I was just looking at this kit. 30 components!

http://www.ebay.com.au/itm/TCP42S1-T...item2ed4221c77

Q401 Q402 Q403 Q421 Q422 Q423 Q621 Q622 Q660 Q661 Q551
D421 D422 D8XX D7XX? Q7XX AND Q7XX?
IC521 IC7XX IC7XX? PLUS SURFACE MOUNT DIODE AND RESISTORS.

Symtom; power LED blinks 7 & 10.

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I can't seem to locate IC677. Everything else seems OK. Q403 and Q402 are more of the 2PG011s so I'll definitely add them to my list. What's the smd P fet? Also, how do you test the 5 pin things marked HA?

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I can't seem to locate IC677. Everything else seems OK. Q403 and Q402 are more of the 2PG011s so I'll definitely add them to my list. What's the smd P fet? Also, how do you test the 5 pin things marked HA?

this is probably not accurate but i found when they blew vcc - gnd would be shorted. Do you know what it is and have data sheet?

Also the 4844 is a cut down version of the 4782

https://www.badcaps.net/forum/showth...ghlight=2pg011

i know what I've done, I have IC1677 but will be IC1677xx, will have to check

P fet is right next to the end of one of the heatsinks SMD, will be Jxxx on it

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

That is the most overpriced repair kit I've ever seen. I'd bet that most of those components are just fillers to justify the price.

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

this is probably not accurate but i found when they blew vcc - gnd would be shorted. Do you know what it is and have data sheet?

No, but I recall reading about it in your other thread.

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

Ok, I found the P fet. It looks like a Vreg. It'snot shorted.

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

Ic16773, This is one to watch with a blown Q661 if you go to schematic and look at the bigger picture

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

Ok, I found the P fet. It looks like a Vreg. It'snot shorted.

cool, I've seen photos of them burnt out on 4782 sc boards

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

That is the most overpriced repair kit I've ever seen. I'd bet that most of those components are just fillers to justify the price.

probably a shotgun approach covering more than may be needed

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

All check over limit.

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

All check over limit.

Yeah, ok but what is OL? I would have expected some resistance there that was measureable. on the 5081 boards I think around 6k

[lookimback]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I checked them again and got 5k. That's weird. Maybe I just didn't press hard enough with the probes.

[tw2005]

Re: Panasonic TC-P42S1 10 blinks, bad SC maybe solved.

I checked them again and got 5k. That's weird. Maybe I just didn't press hard enough with the probes.

sounds more like it. I think the protective coating on the board causes that. It's happened to me plenty. So 5k exactly or a bit more? Sounds like it's ok. All those feed off Ic771 so that would also mean the other would read the same. i would check vin -vout resistance to be confident ic771 is ok.