CurtPalme.com Home Theater Forum

The_JoE · Joined: 18 May 2011 Posts: 14 Location: Jackson, MI

I have a D50HTU and an old D50Q with worn tubes. The 'HTU' is what I have setup right now but I've never been able to adjust brightness on either of them. I did some forum searching and it looks like a lot of people attribute this [and the slight streaking I'm getting on higher contrasts] to a bad PA board.
I'm not afraid to tear the old one to shreds if I can use it to improve the current theater room.

So a few questions:
1. Are the PA boards between the different versions compatible? IE Can I mix and match to get one with less streaking?AND/OR Pull the old board for repair and then put it in the new one afterward?
2. Is it hard to get to?
3. Does anyone have a spare board laying around that doesn't streak and actually has brightness controls?

Any other advice or info is also appreciated!

Thanks,

The JoE

**Curt Palme** · Posted: Thu Jul 19, 2012 12:46 pm Post subject:

There is some interplay between the tubes, HV transformer and the PA board. On sets like the G70, it's almost guaranteed that something will be different, and worst case the set will go into HV shutdown with the other PA board. It may also work fine.. sometimes.

I haven't done enough swapping on the D50s to know what the chances are that it will work, but try it.

THe PA board is an easy fix for the non brightness, figure $125 incl return shipping. THe streaking though can also be caused by the neck boards. For $200 I'll upgrade the PA board and the neck boards if you want. If your tubes are in good shape, it's well worth doing. the HTA version is newer, and I think it came stock with an internal line doubler, Not sure if anything else is different.

The_JoE · Joined: 18 May 2011 Posts: 14 Location: Jackson, MI

Thanks, Curt!

Here's my plan:
I'll try to swap the boards to confirm that it'll still work in the other model. If so, then I can send you just one PA board and run off the other in the meantime. The streaking only seems to happen on the red tube at higher contrasts than I'd like to use so I'm not sure about replacing the neck boards. Then again, these tubes have very little wear on them so it's probably a good idea...
I'll see how much I have off of my next paycheck in a week and get back to you on that part. I'll also update this thread again once I've tried swapping the PA boards.

**Curt Palme** · Posted: Thu Jul 19, 2012 1:32 pm Post subject:

Sure, sounds good. You can always swap the red neck board from the other set (or any neck board, they are all teh same save for the red focus wire length) to check to see if that cures the red. There are several parts that fail on each neck board causing that, I change them all when I repair them.

Cheers!

The_JoE · Joined: 18 May 2011 Posts: 14 Location: Jackson, MI

I finally got around to trying this swap out. The older PA board caused some weird glitches at the top of HD inputs but reduced the streaking almost entirely. This leads me to believe that the streaking (at least most of it) is due to the PA board. I've let it run for a while now with no ill effects or shutdowns. So for anyone looking at this thread in the future, swapping PA boards between different versions of the D50 works just fine.

Here's a few pics:

removal
http://www.flickr.com/photos/83884763@N04/7680251644/

comparison (HT on the left Q on the right)
http://www.flickr.com/photos/83884763@N04/7680251524/

current tube wear
http://www.flickr.com/photos/83884763@N04/7680251430/

current setup
http://www.flickr.com/photos/83884763@N04/7680251346/

Curt, I'll take you up on fixing this board. Should I just PM you for payment, shipping, etc?

**Curt Palme** · Posted: Tue Jul 31, 2012 3:42 am Post subject:

Shoot me an email to curtpalme@shaw.ca

Thanks!

The_JoE · Joined: 18 May 2011 Posts: 14 Location: Jackson, MI

I've got the newly repaired PA board in and can finally do a proper adjustment of brightness and contrast. This cleared up almost all of the streaking problems as well.

Thanks a bunch, Curt!