Update on PTK195 and a request on pioneer SD-P55A3-K

Put a video camera on it and look for an arc as it shuts down. Had one with an arcing CRT last year that made me nuts.

Also, did you resolder the several hundred ring cracks on the board that you got from Pioneer? Most boards from them need it even though they are "rebuilt."

Leonard

Yes, 1001 shiny solder joints on that deflection board. COMPLETELY! :)

Didn't stop the shut down after 10-15 minutes. There is no "click" or "snap" that goes with it. I can turn it back on right now without having to unplug to reset x-ray protection when shut down occurs.

Cheers, Wizard

Re the SD-P55A3

Are you turning it back on with the large power button or the remote? The big power button on the front disconnects the mains, using it is just like unplugging the set.

There are shutdown LED's inside this set to monitor the powerdown circuit. When the set shuts down, look on the deflection board for a lit LED near the relays. This is the main powerdown monitor, and if it is lit the set is going into shutdown. If you can confirm it is actually going into shutdown then we can look for what circuit is tripping it

There are some other LED's for the PD circuit that will light very briefly when the set trips shutdown. You will need to be looking at them with the light off in the room so you can see. If any of the LED's light even a little bit you can narrow your search down. These sets had LOTS of problems with the amp assembly and digital convergence DAC board. They had a fault that would cause excessive inrush current on the +/-25V lines and make the set shutdown.

On the amp assembly find the shutdown LED and watch it very close. I'll almost bet the problem is there. Another thing that may help is having an assistant power the set on, and look at the fuses for the + and -25v lines that run the convergence IC's these fuses are on the deflection board behind a small transformer. Easiest way to see them is to slide the board rack back and tilt it towards you. Many times I've seen a problem on the amp assembly draw enough inrush current to heat the fuse red without blowing. Stress over time eventually causes fuse failure, and be sure to check the fuses and make sure they are the correct size, I have seen techs put a larger rated/slow blow type fuses in these sets and think they fixed it, which is not proper at all, but it happens.

Jammy

Forgot to note in my other response if the set is not going into shutdown, check the power_on output from the micro and see if the set is just shutting itself off. Bad microprocessors on these sets are uncommon, but not unheard of. You might try heating the micro with a hair dryer to see if the set shuts down sooner.

Jammy

SD-P55A3-K Shuts down 10-15 minutes later. I have service manual (real thing) for it no trouble shooting section.

Thanks, this time I paid attention to that red LED in PSU area. And this time I heard "Whu-THUMP" of speakers when TV shuts down and red LED lit. You're right this time, I wasn't thinking, that big power button is "hard power button". :)

The soft power button didn't get tv back, the hard power button did.

The convergence amp board with smaller green daughterboard is currently on the bench going through resolder job. This did not react to hitting with beat up plastic stick (old 5" front cover from 5 disc player). There is no LED for this model, this is very old type, 1992.

Remember caps I listed is all what I changed out in power/deflection board; four 220uf, three 47uf, one 1uF, one 100uF and couple caps for the regulator IC (typical 78xx). These caps flunked the ESR meter check.

Interesting thing to say about that vertical circuit, no electrolytic cap for pump charge. That's something to say!

Hope that can keep suggestions coming. :)

Cheers, Wizard

There should be an LED on the amp assembly, near the bracket for the DAC board and close to where the ribbon connector from the DAC connects to the amp assembly. It is very small and hard to see, and does not have a latch circuit like the main PD led does. If it's indicating it will barely flash briefly at the moment of shutdown. Should be on the rear of the board as it sits in the set. I'm sure all of the 50/55A3 and A5 sets had an LED there. Important to note that NONE of the LED's have a latch other than the main PD one. The others will barely light then go off on shutdown, you probably won't notice it unless the room is very dark. Were the fuses correct? 4a fast blow, I believe, on the deflection board +/-25V supply lines.

Jammy

Well,

Today was the up and close personal with the convergence amp board, replaced all 10 220uF, 4 100uF, couple 330uF (6.3V). Tentatively fixed since TV is still up for 45 minutes before I had to leave early for bus for the day. Reason for this particular day was my nice boss's 1992 3.0 MPV is in shop for rack replacement. I get a short ride to bus stop daily so I don't have to change so many buses on that particular evening, I had to do 4 bus changes.

This TV was working for years till caps dried up enough to stay shutdown for good. That particular problem would had been done years ago since Pioneers told shops to replace this convergence stuff if one comes in for this reason LOOONG ago. This one was in service for long time already and had problems unrelated to this second problem that showed up after rebuilding the power/deflection board.

Oh, there is no LED in the location for the convergence stuff. BUT there is LED *under* the DAC daughterboard and this is for vertical circuit trip. This boggles me to hide this one. :-O

By the way, I have newer Pioneer that's is now ours, needs caps so I'll know what to do with that one. Whoo hoo.

With closing comment, be prepared to spend time with these, give 2-3 hours minimum and at least 30 caps on both deflection/power and convergence boards. Quicker to ESR them in one pass and use permanent mark those duff ones. Solder, solder throughly!

All 10 220uF 35V reads appox "22" on bob parker's ESR meter and couple

100uF for the input side of +/- 5V regulators reads "1", others were due for swapping so this got done.

Stay tuned! :)

Cheers, Wizard

Lol I knew there was an LED on the thing somewhere.

Hope it works out for you

Jammy

Ok, definely fixed, passed 4 hours now and ready for owner to pick up. :)

Cheers, Wizard