Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

[Phil Stasik]

Re: Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

I thought that I should try to isolate the heating of my power supply board with a styrofoam cup as a heat dam, rather than the cardboard that i had used before. The results were curious. The start-up success dropped to about two starts, then one failure.

Previously, using cardboard to isolate heating, I was getting completely normal starting when I heated the upper left corner of the board. I'm now suspicious that the cardboard must have been leaking heat to a larger area than I had thought. Maybe the whole damned board is just heating up, as I try to isolate the hot air to one spot.

I'm attaching phots of that very low tech method of isolating the heat to a limited area -- at least for a few minutes until the rest of the board warms up.

I'm able to monitor the component temperatures accurately with a "K-Type" thermocouple and my multimeter.

It seems that I'm back to heating a large are of this board, in order to get reliable starts. Gee I wish that I could find a Pioneer Plasma PRO-FHD1 service manual that could give me some pin voltages to check, or some other troubleshooting guidance...

[diif]

Re: Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

The two main things that are affected by heat are electrolytic capacitors and dry joints.
I'd concentrate on any caps you haven't changed first, then inspect for dry joints.

[Phil Stasik]

Re: Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

Thanks diff! There is one particular solder joint that I have been looking at with suspicion on the upper left corner of this board. It's a "snap in" pin on one of the big caps that I pulled, tested, re-installed, then pulled and replaced. That is rough on the board -- even with a gentle touch.

I really do appreciate your advice!

I'm going to pull the board again and give it another good look.

I did find a digital copy of the Pioneer Service Manual, and bought it, in the hope that it might have some additional wisdom. It's interesting, but the "schematics" are really just block diagrams, and the verbal guidance to the Pioneer technicians who are troubleshooting this problem is to "replace the power supply circuit board". I understand completely. Techs don't usually get into replacing board components.

I'm getting much faster at pulling and replacing this board...

[Phil Stasik]

Re: Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

Looking very closely at the soldering on this board reveals that most of the joints are not shiny, but rather buff, as cold solder joints look. The soldering that I've done so far looks brilliantly shiny compared to the factory work, and I'm no expert.

I also found a small component, that I'm guessing is an SMD Zener Diode that looks as if one of the terminals is (intentionally?) not soldered. I've attached 3 images. It looks weird, and it seems to be the only component of its type on this board.

I have no experience soldering SMD stuff, and could imagine messing this one up, if I tried to add solder to the center terminal. looking at it with the strongest magnifier that I've got, it seems that there may actually be a very tiny bit of solder under that central pin.

What do you think?

[lotas]

Re: Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

The upper part is soldered well, and it goes to the middle output.

[Phil Stasik]

Re: Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

Thank you Iotas! That is a curious way to mount a component -- with a terminal just floating. Thanks for filling in a gap in my knowledge!

I do appreciate the help of everyone on this forum!

[Phil Stasik]

Re: Pioneer PRO-FHD1 Elite Plasma Monitor Start-Up Problem

I took some time to look very closely at the entire board with a magnifier, looking for cracks in the solder or printed circuit material. I did not find anything obvious, but I did re-heat and clean up a number of solder joints that looked like cold solder joints.

After re-installing the board, and powering-up, I saw a spark, so I powered off and have not yet pulled the board again to inspect it. I'm not giving up yet, but it's really time for professional help, I guess.

I fear the worst.

We may be getting a new T.V.