Pioneer PDP-V402 reaching EOL?

[pentium]

I had one of these hanging out at my old employers and they asked me to take it away. I had originally used it shortly for a photo or two after we got it from a TV repair shop ant it always had this weird problem. I liked it because it supports Sync on Green VGA signals.
If you first powered it on cold it was fine and the whole screen was okay but even if you gave it a dynamic image (one of those pixel flasher videos on youtube for example) you would start to see a lot of blue or black spots in the middle band of the screen after a few minutes. The tops and bottoms were however fine. The spots were also not hard edged so this isn't the fault of letterboxing not burning parts of the screen.





Is this just the unit being especially old or is this a faulty hardware problem?

[tom66]

Re: Pioneer PDP-V402 reaching EOL?

Is that a plasma display? If so, check the erase and scan voltages are good - they tend to drift when the temperature inside the unit warms up.

[pentium]

Re: Pioneer PDP-V402 reaching EOL?

Yeah it's a plasma. I can't check either voltage right now because I don't have access to a proper service manual to see where either are located in the system. Best I can find is the Field Service Guide.

[tom66]

Re: Pioneer PDP-V402 reaching EOL?

Yeah it's a plasma. I can't check either voltage right now because I don't have access to a proper service manual to see where either are located in the system. Best I can find is the Field Service Guide.

Open it up - they are usually indicated on the board. Take good pictures.

[pentium]

Re: Pioneer PDP-V402 reaching EOL?

Question is, which board? There is a LOT going on inside a plasma display.



A lot of the connectors are already listed in the field service manual and almost none of the test points are. They are equally as unmarked on the boards.

[tom66]

Re: Pioneer PDP-V402 reaching EOL?

Wow, Pioneer certainly don't disappoint. I just realised this is a 40" PDP, 640x480. Old school stuff!

On the lefthand side of the PDP, there will be a driver board. It is known as the Y Drive in Pioneer terminology I believe. It is probably hidden under the other stuff because there is basically no room left inside!

There may be adjustments there, there may not be. They could also be on the PSU. Is there a voltage sticker anywhere on the PDP? There usually is, but I've never serviced a Pioneer before (I want to though.)

[pentium]

Re: Pioneer PDP-V402 reaching EOL?

Yeah, it's an oldie. I like it because it supports Sync on Green so out of the box it works with Silicon Graphics products.
The Y driver boards are located on the right side of the monitor int he above pictures and page 8 in the manual. Visually the boards are identical save for a resistor stating either board A or board B and a few parts relocated to make room for the AC line filter.



The power supply is apparently the board at the top and on page 5

[tom66]

Re: Pioneer PDP-V402 reaching EOL?

Has removing the board given access to a panel sticker indicating panel voltages? There is only guesswork if you can't find the voltages as these PDPs have about 5 different voltages (Vs, Va, -Vy, Vscw, Ve... to combine LG&Samsung terminology.)

[JimmysTGP]

Re: Pioneer PDP-V402 reaching EOL?

The last time I seen a picture like that was on a old samsung plasma, where I found 3 bad capacitors(not swelled) on the Ysus board. So Id say check for ESR on all electrolytic capacitors on that board. However I do have a Pioneer Elite PRO-436 here that I will eventually have get to. Hopefully it has that kind of issue, but I'm affraid it may be the panel. Let us know what you find.

[pentium]

Re: Pioneer PDP-V402 reaching EOL?

There is actually a sticker for the voltages attached just above the PSU board.

VSUS: 174.8v
VOFS: 139.9v
VRST: 184.2v
VADR: 59.8v
VCSP: 37.2v
Vh: 161v

Shall I be looking for the test points of the above and checking each one?

Those are the printed values when the unit rolled off the line in November 1999 (holy crap, this is one of the first consumer Plasma displays!). All the capacitors in the system are Nichicon, KMG, or UNC.

[JimmysTGP]

Re: Pioneer PDP-V402 reaching EOL?

My decision would be that if your getting your picture at all, your Voltages should be there, they maybe off a little, which could possibly be your issue. Check to see if and how far off they maybe. After adjustment check your picture then and see how much progress you've made. Do keep us in the loop.

[tom66]

Re: Pioneer PDP-V402 reaching EOL?

There is actually a sticker for the voltages attached just above the PSU board.

VSUS: 174.8v
VOFS: 139.9v
VRST: 184.2v
VADR: 59.8v
VCSP: 37.2v
Vh: 161v

Shall I be looking for the test points of the above and checking each one?

Those are the printed values when the unit rolled off the line in November 1999 (holy crap, this is one of the first consumer Plasma displays!). All the capacitors in the system are Nichicon, KMG, or UNC.

Yeah, very, very well engineered. It looks more like an business/commercial display from the marketing material.

I would check the VCSP, VRST, VOFS and VH testpoints. VSUS and VADR probably aren't causing the problem (they would just cause a dim picture if too low, and too high would probably cause the PSU to shut down.)

[pentium]

Re: Pioneer PDP-V402 reaching EOL?

I was able to locate all but the VRST test points. The readings were as follows:

VSUS: 172.8v
VOFS: 136.9v
VRST: Couldn't find it
VADR: 57.6v
VCSP: 35.7
Vh: 143.3

While all of the test points showed the readings were a few volts off, Vh is almost 20 volts lower than normal.

[tom66]

Re: Pioneer PDP-V402 reaching EOL?

I was able to locate all but the VRST test points. The readings were as follows:

VSUS: 172.8v
VOFS: 136.9v
VRST: Couldn't find it
VADR: 57.6v
VCSP: 35.7
Vh: 143.3

While all of the test points showed the readings were a few volts off, Vh is almost 20 volts lower than normal.

This is probably your problem. Plasma displays are extremely dependent on those voltages. If you can adjust that back to nominal and the picture still isn't great adjust all of the others to within +/-0.5V of their sticker. (That's what Panasonic say for their PDPs.)

Vrst may also be important but in some PDPs can only be measured with a scope - do you have one?

[pentium]

Re: Pioneer PDP-V402 reaching EOL?

I have a scope handy. Of course, I first need to find the VRST test point first.

[pentium]

Re: Pioneer PDP-V402 reaching EOL?

BuMP.
So I finally dragged up a decent test pattern generator and with a full white signal I tried again. This time I was able to fix the weird fuzzyness on the lower half by adjusting Vh and the overall freakyness went away while adjusting VRn. There's still some flickering but it's nowhere near as bad and given the age, I'll let that pass.
The only part that concerns me is how much VRn was adjusted. The label didn't state what voltage it should of been so I noted the initial voltage (-184.2v which means it's the same to Vrst (only negative), if I could find that damn test point) and I had to go all the way to -208v which is the upper(lower?) limit for the VRn adjustment for things to really clear up. I'm hoping that in the long run that won't hurt anything.
IT also seems that if I change the brightness or contrast from the OSD controls, the freakyness starts coming back so I can't touch those anymore.

[Shinju]

Re: Pioneer PDP-V402 reaching EOL?

I am only necro bumping this since this is one of the first threads to pull up on google when searching for this unit.

If anyone is reading this I am looking for the following parts for this Pioneer PDP-v402 unit.

Stand legs/bolts
Left and right detachable speakers
XVGA plug and play module


Thanks!