Pioneer KRP600M - Intermittent picture distortion on part of screen

[Blueagent]

Started this in the guide sticky thread, but will continue it here.

Original post:

I have a Pioneer 60" plasma (KRP600M) that for the last several months has had an issue pop up intermittently. Basically, I get vertical distortion in the top middle section of the screen. Always in the same place (if you divided the screen up into eight square segments, it would be the third from the left at the top). See the pics attached.

Like I said, it comes and goes. It can disappear for weeks at a time, or linger for weeks. It seems to be around more often than not these days though.

Any thoughts?

Feedback was that it could be a loose connection. I will take some pics of the investigating for loose connections process and maybe this will help someone else...

If anyone else has any thoughts on it, I would love to hear them.

[tom66]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Can you take the back cover off and take pictures?

P.S. Nice TV... I am jealous...

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Will do. Have help coming shortly to lift the thing off the wall (it weighs about a hundred pounds).

And I do love this TV. Got it on clearance almost 4 years ago when Pioneer was getting out of the plasma business. My wife and I were just closing on our first (and current) house and living with her parents for about 6 weeks before we could move in. I saw the deal on this TV and had to jump on it...and it's not like I could leave it in the box for a month (had to check to make sure it worked correctly after all right?)...so we had a 60" tv crammed into her old bedroom about two feet off the end of the bed. It was like sleeping in an IMAX theater...

[tom66]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Well, I am always on the look out for a faulty Kuro -- unfortunately they're about as rare as hen's teeth! I have to settle for a "mere" faulty Panasonic plasma now and then.

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Cover is off. Here are the innards. Looking for loose connections or a button that says "push this to fix problem".

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

I have gone over it in detail and there are no loose connections at all. I checked all connections anyway and reassembled and the distortion is still there just like before (I figured this was a shot in the dark anyway).

Based on the position of the glitch, I looked very closely at the top address buffer board second from the left (as you look at it from the back) and traced it to the logic board making sure that connection was sound. It was solid all the way. No obvious issues with the flat wire, the connection, or any of the board components.

One question is, if this is a buffer board issue, are all the address buffer boards the same or is each one a particular part number? Some of them appear to be identical. Can a buffer board even be replaced on a Pioneer or is it essentially permanently connected to the pdp? I have seen videos of people disconnecting buffer boards (usually ones that are attached to the Y-sus board) from the pdp, but mine appear to be connected via adhesive or something (I am obviously not an expert here).

I am thinking this may be beyond my abilities and I will have to fork over the hundreds of dollars just to get a tech out to look at it and see if it is even repairable. It kills me, because this is such an awesome TV, to have something annoying like this pop up and have so few resources for Pioneers is frustrating.

I took more pictures that I can post if anyone would like to see them.

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Having done some more research...I may be calling things by the wrong name (sorry)...anyway, the service manual calls the part that appears to control that portion of the screen the 60F ADDRESS L ASSY. It appears to be basically hardwired to the pdp via a TAB bond? Actually 4 of them. Service manual labels these driver IC's. Could one of those be bad (or at least have a poor connection) and be causing this? Is there anything I can do if that is the case? Like I said before, I didn't see anything specifically wrong with any other connections, boards, etc. Is there anything a service tech could do for this?

[tom66]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

It is unlikely to be one of the driver ICs on the panel because it affects more than one chip area. You may have a defective logic/control board.

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

I talked to a TV tech who seemed pretty pessimistic about the situation. He thought it was a bad panel.

I agree that if it was a bad IC connection or something, you would think that just one relatively small band would be dead or something, not the entire area controlled by the address buffer. So, if it isn't the individual IC drivers, then it would have to be the address board itself, or the connection to the logic board (either the ribbon or board itself), right?

Of course if it is the address buffer, it would appear that I am out of options, as that is permanently affixed to the pdp via a TAB bond. Do you have any experience with logic boards failing and only affecting one address buffer? Or doing so in such a way that it only causes mild, intermittent distortion, and not dead areas/bars/etc?

Not sure where to go from here...

[tom66]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

I've not personally seen address boards fail, but I have seen the connectors get corroded or become loose over time, causing very similar symptoms. I have heard others discussing failed logic boards, which can cause similar symptoms (and only in one region) too.

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

well, that is encouraging. Do you have a site you recommend for purchasing components?

Also, which connectors are you talking about? The ribbon cable? When I looked yesterday everything seemed pretty tight and clean.

[tom66]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Yeah, I'm talking about the cables from the address boards to the logic board.

ShopJimmy, eBay, and other suppliers you can find on the 'net -- just make sure you get a returns policy.

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

bought a new logic board from shopjimmy for $25. Figure for that price it is worth a go, even just to know whether it is the logic board or not.

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

***UPDATE***

Just in case anyone else might have been interested in my KURO issues...

I finally got around to replacing the digital assy in my KURO to see if that was what was causing the distortion issue (thanks a million to Tom for pointing me in the right direction)...long story short, my picture is back to crystal clear. Problem solved. Again, can't thank Tom enough for the assist!

For those that want to know the process:

I found a service manual for my KURO online, which was a huge assist for disassembly and having confidence in identifying the various assemblies. For example, my digital assy is positioned underneath a couple other boards in my TV, and if left to my own devices I may have attempted to remove those boards to get to it. It would have been a nightmare. Luckily, the manual was actually very clear, and I was able to lift out both boards right on the bracket they are attached to just by undoing four screws.

Anyway, the removal and replacement process was very simple (like my previous post said, I had gotten the replacement part from ShopJimmy...great experience with them). Aside from a stupid snafu with not realizing that I had knocked the main power switch off and having a few minutes of terror when I could get the set to power on, it was very straightforward.

I also had to find a way to get into the factory menu, which was sort of difficult. The only way to do it is with a pioneer service remote, which I do not possess. I was able to dig around on the net and find the hex code for the command and manually load it onto my harmony remote. Not at all straightforward, but pulled it off eventually. As a bonus, I got to see that I only have 13000 hours on the set. Lots of life left.

I am really happy to have it back working, and for $25 at that. Thanks again for the help everyone!

[tom66]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Nice fix! I will now have to keep an eye out for a discarded one like this

[Blueagent]

Re: Pioneer KRP600M - Intermittent picture distortion on part of screen

Ha...no kidding! Again, seriously Tom, thank you so much for your help! No way I would have pulled off the fix without your input! Sending positive Karma across the Atlantic your way!