Panasonic TC-P58VT25 10 blink

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

I did look at the old parts and it for sure was a 56. Like you said, the service manual shows a 63. Oh well, at least they are not exploding on me. I will get back tomorrow with results, now its spend time with the wifey. Oh by the way, the r551 was reading 4.7 k. I have spares, so I will replace along with the Q551. Are these common areas to look at or out of the ordinary.

Well you can get variations in failures and I get caught out too. You do a few with the same bits broken and get complacent.

It is a common area to be thorough with.

just updated the 5081 thread with one a bit different. Plus this is a different board although it is essentially a 5081 on steroids.

IC521 always high chance it's shot and then from there out you need to check.

When you look at the schematics it makes some sense how these all tie in.

So if R551 which should have a marking 100 is high , if you look close with a magnifier there maybe a brown spot.

I'd say good chance Q551 is blown

last 5081 had Q551, r551 shot, burnt gate resistors, d451 shot .

The more you do the more you learn.

that's why I put D451 on the list last so you'd check everything else first.

I've had a couple of boards now which went 6 blink, no damage and it was D451 plus the other bits i mentioned.

Maybe wifey can spent some time in the workshop, you're just about done

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

On a tangent, I just quickly knocked up a 5066 board I had laying around and put a RJP56F4A in for the Q661 in lieu of the RJP63F3A. I figure if it's good enough for an overgrown SC for a FHD 3D 58" it be good enough for a pissy HD 42".

Swapped in the board and set it up in the bedroom, I'll report if it goes bang. It's actually it's second repair but I suspect the SS that let go took it out.

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

Well, no joy in mudville. Still have the 6 blink. Although the SC board led does not flare up anymore. It stays a solid intensity, but shuts down about 3-4 seconds later.

I did ck all the components I replaced on this last go and they are ok. Do you think the shorted D451 could have blown the IC521.

I have a spare, or if you know of anything else. I can't help but think it's related to something I have replaced, I even retouched some of the components I replaced.

I know this board can be nerve wrecking, but I sure don't want to give up. Maybe I should get the wife in the workshop, she would probably run circles around me. After 31 years she would probably decline.

Thanks for all your time on my board, and you are right, always learning even at 64 years old!!!

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

I started checking everything in that area and here is the results.
r466 should be 56k-measured 65k
r467 should be 82k-measured 58k
r468 should be 82k-measured 94k

I checked my readings several times-these are all in series. I sure hope you don't have to remove them to check.

If you suggest replacing, do you know what size these are. The pn is
ERJ6ENF8202 for the 82k. not sure how to tell from the pn.

[Alastair E]

Re: Panasonic TC-P58VT25 10 blink

Q661 is strung between V-SUS of 220V and the Neg 190v rail so I guess a 56 would be OK, as there's about 410? odd volts across it, not including any resonance peaks/pulses or other effects from panel or ERC...

Ive never seen a 56F3/4A used for a Q661--in Any set, would recommend you use 63F3A/4A in that position, just to be safe--When 661 craps out--It takes a whole load of stuff with it....!

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

Q661 is strung between V-SUS of 220V and the Neg 190v rail so I guess a 56 would be OK, as there's about 410? odd volts across it, not including any resonance peaks/pulses or other effects from panel or ERC...

Ive never seen a 56F3/4A used for a Q661--in Any set, would recommend you use 63F3A/4A in that position, just to be safe--When 661 craps out--It takes a whole load of stuff with it....!

I might change that out with the 63 but I was hoping to get it up and running first. This one looks like everything checks. I did have some bad readings on the resistors but I think it could be my fluke. I do have the other board I am using for comparisons and everything is pretty much the same. Driving me a little crazy!! I will keep after it and hopefully find something-thanks for your help.

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

Q661 is strung between V-SUS of 220V and the Neg 190v rail so I guess a 56 would be OK, as there's about 410? odd volts across it, not including any resonance peaks/pulses or other effects from panel or ERC...

Ive never seen a 56F3/4A used for a Q661--in Any set, would recommend you use 63F3A/4A in that position, just to be safe--When 661 craps out--It takes a whole load of stuff with it....!

Well here we go again. I put the board back in without really too much except check readings and powered it up and small crack noise. Guess what, the 661 blew and took out all the dg402's and dg502's. I think you jinxed me. I will order the 63 version and try again. I verified that a 56 came out and the manual shows a 63. I am sure there is an underlying cause that this happened so back to the drawing board 10 blinks.

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

So was anything changed? what about R551 & Q551.

I was on encompass and they sell 402 and 502 at a buck each.

https://www.encompassparts.com/item/...2RP/Transistor

https://www.encompassparts.com/item/...2LW/Transistor
you're going have to be sure it's just them and recheck every part, basically start from scratch.

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

yes, I changed both parts and had it in the circuit a few times and was 6 blinks. I had just checked every resistor, diode close to Ic521and I was going to ck some voltages on startup before the 6 blink code and that's when I heard a small crack. I have removed all the shorted parts and was checking everything else and found IC771 with 55 ohms across it. I removed it and checked the pads and the short is still there. I guess I will have to look at the schematic and start tracing back. I really thought the shorted diode was going to do it. No such luck. I will order parts and report back again. If anyone can think of anything else to check in the meantime. I did ck ic521 vcc to ground and it looks ok.

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

Ic773 q701 q702 q818 . Optocoupler 9856--2 near sc20 can sometimes cop it

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

I will check all those, I will probably report in once I get the parts. Thanks for your help!!!

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

I would put the first 4 on the shopping list and replace

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

Ok, will do. Is there an easy way to ck these, or should I just replace? Guess what I found when I was cleaning up the work shop (which is my garage) a baggie full of rjp63's. I hope I wont need them all but can cross it off my list.

Just a question, I had the 2 diodes I didn't replace, I think they were AL50 something. In diode mode they checked at .377 volts. Is that too low or should I add them to my list. Thanks

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

They're fine

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

Ic773 will be short so i'd say replace all those plus you'll have to be sure ic771 is functional as it supplies 5v for Ic773

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

Ic773 will be short so i'd say replace all those plus you'll have to be sure ic771 is functional as it supplies 5v for Ic773

So right now I have IC771 removed and still shows only 55 ohms across the pads on the center and left leg.

Are you saying IC773 is shorted and thats why I still have a short on the pads of the IC771?

I printed off each page pf the schematic-4 total and my plan is to start on the second page and check every part and cross it off as I check it.

I might need some help on some of the IC's but I will report as needed.

I dont count my time spent on these boards otherwise I would probably pitch it.

Any good source on some of the smaller parts, like the IC771 and 773, the usual blown transistors are readily available.
Thanks

Oh by the way tw2005., I keep learning little stuff along the way, like putting spaces between my replies. Easier to read

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

Wow tw2005. I just got finished scanning your 20 page post on the 5081 rebuild. I guess I shouldn't feel too bad at this point.

Just more to learn.

[tw2005]

Re: Panasonic TC-P58VT25 10 blink

So right now I have IC771 removed and still shows only 55 ohms across the pads on the center and left leg.

Are you saying IC773 is shorted and thats why I still have a short on the pads of the IC771?

I printed off each page pf the schematic-4 total and my plan is to start on the second page and check every part and cross it off as I check it.

I might need some help on some of the IC's but I will report as needed.

I dont count my time spent on these boards otherwise I would probably pitch it.

Any good source on some of the smaller parts, like the IC771 and 773, the usual blown transistors are readily available.
Thanks

Oh by the way tw2005., I keep learning little stuff along the way, like putting spaces between my replies. Easier to read

IC773 TC7SH14F, TI have a direct replacement

SN74AHC1G14DBVR

IC771 TA78L05, should be able to find a sub but it's current output is a little higher than most in this size.

I don't know who Mouser, Digikey? but I hear shipping can be crazy. I go china but takes forever.

and yes, ic773 will be the short , almost assured of that.

If it makes you feel better , I was up to 2am on a 4782 that 7 blinks, nothing blowing up and Vscn, Vad voltages are correct that's doing my head in. Very sleepy today.

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

Well tw2005, I can sure tell you are persistent. Usually it pays off, but sometimes it can be a real let down.

I fully thought my 5175 was going to work, but these particular breed of Panasonic SC boards can drive you crazy.

I will update as I go along. I assume on the IC771 your are looking for 5-6 kohms from gnd to output and in mohms to input or is it the other way around

[gdawg]

Re: Panasonic TC-P58VT25 10 blink

I do have the other 5175 that I can compare readings to, just a lot of time..