Panasonic TH50PX60U Power Problem

[teg33]

Re: Panasonic TH50PX60U Power Problem

I bought/downloaded the full service manual today. I see 2 signals that might be what you are looking for:

1) There is an F_STB_ON signal that comes from the DG board and goes to P board connector P25 pin 13. That is one of the test points in the "no power troubleshooting chart" that I have looked at before. When the 2 clicks are heard upon applying power, that signal is 2.6V until the 1 click is heard and things go into power save. When no clicks are heard upon applying power there is 0V on this line.
2) There is an F_STB_15V signal that comes out of the P board connector P10 pins 1-3 and goes to the PA board (to a regulator circuit that generates SUB9V, SUB5V and SUB3.3V). Should there be F_STB_15V voltage when the set is powered up? I left the set on since it's the first time it powered up in 2 days. I checked the voltage here and found 15.7V on pins 1 and 2, but nothing on pin 3. I went to the PA10 connector pins 1-3 which is where this cable runs. Same thing there, 15.7V on pins 1 and 2, but nothing on pin 3. I presume there are 3 wires to handle the current because they all connect once on the board. I checked the TP16 test point on the PA board and voltage is good there. I also checked the SUB9V, SUB5V and SUB3.3V voltages and they are all good. I guess this means the circuit board track is broken open on the P board running up to the P10 connector. Apparently it doesn't matter since there are 2 other wires.

I was a little surprised the F_STB_15V signal was present when the board was powered up. Should I get the set into a failed mode and check this signal again?

By the way, the set has been powered on for 90 minutes without issue. This is consistent with earlier behavior, once it's on it is good.

Thx

[tom66]

Re: Panasonic TH50PX60U Power Problem

I hope you did not pay too much for the manual, because it is available for free on Elektrotanya.
http://elektrotanya.com/?q=showresul...oria=&kat2=all

As for your issue, I am well past knowing where your problem is exactly. But I will say that your intermittent fault is more likely to be on the DG board than the P board. I would suggest that touching up some solder joints on the PSU may be in order, as I recently fixed a 2008 Panasonic with cold solder joints on the PSU.

[teg33]

Re: Panasonic TH50PX60U Power Problem

Paid $13, should have asked first.

Thanks for all your help, do you mean the P board when you say PSU?

I am going to order both a DG board and a P board since the various paths through the chart pointed to these 2 boards. I can get them used for a reasonable price with a return policy. I will try the DG first. If it doesn't fix it I will also replace the P board and keep my fingers crossed.

I think I read somewhere that Panasonic recommended replacing another board (maybe PA??) when replacing the DG board because they were so closely linked and difficult to discern which had failed. Do you know anything about that and whether it's worth doing?

[teg33]

Re: Panasonic TH50PX60U Power Problem

Found the other forum, it says "Panasonic even recommends ordering the PA if you're going to replace the DG "since it may be difficult to determine whether the PA or the DG board is defective.""

What are your thoughts on this advice? Nothing in the "no power" flowchart ever points to a PA problem so I'm not inclined to replace it.

Also, let me know what you meant by PSU?

Thx

[tom66]

Re: Panasonic TH50PX60U Power Problem

Do you have a PA board? I thought that was dropped on the PX60 and only present on PZ70 1080p.

[teg33]

Re: Panasonic TH50PX60U Power Problem

Yes, I have a PA board. Some of the test signals were on that board.

[teg33]

Re: Panasonic TH50PX60U Power Problem

When you said PSU did you mean the P board?

[tom66]

Re: Panasonic TH50PX60U Power Problem

Yep P board = PSU.

[teg33]

Re: Panasonic TH50PX60U Power Problem

Quick question: Does anyone know how to discharge all the voltages on the P board to make it safe to remove? I see two 18Kohm discharge resistors that look to be in series. Do I just connect ground to some place on these?

Any suggestions on where to look for cold solder joints on this board?

Thx

[tom66]

Re: Panasonic TH50PX60U Power Problem

After leaving the board alone for 30 minutes, take a screwdriver and discharge the capacitors by shorting across them. The energy in the capacitors should be minimal. If you want to do it quicker, a 1K 10W resistor works well.

[jtgamble89]

Re: Panasonic TH50PX60U Power Problem

I have the exat same tv, when I plug it in it gives the 10 red light blink. only thing is, three relay clicks are heard all together. 1.2.3 there is no space between the second and third click. What doses this mean? what can I do?