Pioneer Elite PRO505-PU Plasma

[dfergy54]

Just happened on this thing , it is a 2 piece setup with a reciever like piece where the cable and or inputs are made then proprietary cables X2 to the display.

On Initial turn on it has great sound but no pix,, After about 15 minutes a pixture begins to sho up at the top and bottom of the screen.
About 60 mm band zcross top and bottom, as the set warms up this will eventually expand to full screen eventually gets a so so picture.
Not sure how to describe the warmed up picture, so I will include a picture.
Found both Users Guide and a very basic service manual online.
Inside the set there is no sticker with VSUS or anything else. Checked some of the supplys as best I could with no schemo, got 440 volts and a more regulated 380 volts on the main PS board, All the trim pots are Glyptol painted.
Apparently many of the adjustments on this tv are done via laptop serial interface with special adapter.

Pretty Different eh, anybody have any ideas?
The TV on the left is a rear projection with the same picture as the plasma on the right. The rear projection looks pretty good for what it is, and my pictures may not reflect that.

[tom66]

Re: Pioneer Elite PRO505-PU Plasma

I've had cyan discharge when VSUS or -VAD was too low - not sure what equivalent is on Pioneers though.

I know freakaftr8 on here had a Pioneer with 70,000 hours on it, and it had a similar fault, he put the VSUS up to 240V from around the nominal 210V. No idea if that's any good for the panel/sustains though, it's well above their nominal ratings.

[dfergy54]

Re: Pioneer Elite PRO505-PU Plasma

Thanks for the Info Tom, I am attaching the UG and SM.
There are 2 caps on the PWR supply Large Nichion 330 Uf 450 Volt CE 105 degree , part of switching PS, that seem possibly slighty Pooched, But the power supply comes up immediately with the 380 volts and stays there, can,t find anything so far causing the long screen rendering delay of 15 mins.

[tom66]

Re: Pioneer Elite PRO505-PU Plasma

Its the panel - as it warms up the gas becomes more able to discharge.
Essentially the only way to fix it is to adjust the voltages to fit the panel better.

[dfergy54]

Re: Pioneer Elite PRO505-PU Plasma

I found the adjustment for "VSUS Adj" and slowly moved it untill I got an acceptable picture, looks pretty good.
But it still takes a good 15 minutes to warm up to a full rastor.
They didn't label much in the way of test points on this set.
Either a supply is taking a long to ramp up or some kind of blanking/timing issue untill warmed up.
Or is it just that the tube is worn out and it will take longer and longer to come to full rastor before it fades out?