D50 - No brightness adj

Yes, the same thing happened to my D50. It used to work, but once I had the projector dialed in I almost never used it. Then when I tried, it didn't do anything.

The problem is in the PA board. There is a set of three capacitors that tend to go bad. When they do, the brightness control no longer works.

If you're adventurous, you can take the PA board out de-solder them and replace them yourself. They're big and pretty easy to work with (its not like your trying to replace surface mount components). I got a bunch of them since none of my local electronics stores had the right kind and the online places had a minimum order of like 50 pieces. Let me know if you'd like them and I'd be happy to send you a set.

Alternatively, you can have someone fix your board (Curt offered to look at mine I think). Or maybe you can get someone to swap your bad one for their good one (which they'll then fix and resell). Or you can take a look on the bay or videogon and see if you can find a replacement.

Kris

They are 4700uF 10v caps. I have a bag of them so let me know if you want I'd be happy to send you some. They are in the red circle on this picture:
http://www.vidya.com/D50/D50_PA.jpg

Kris

I have had good success repairing the A boards if you're stuck.

BAd tubes with low emission can also cause the no control of brightness issue.

Wild Willy,

From my poor memory, the brightness control (G1) in the form of a dc voltage goes to the neck board via the one of the multipin connectors. If you vary the brightness level do you see a voltage variation at the input to the neck board?

I don't have the service manual in front of me otherwise I'd give you the connector/pin number.

PDFs of the service manual (broken out into the different sections) can be found here:
http://www.vidya.com/D50/bak/

Please do find the problem. I have one in the attic with a repaired PA board that did not fix the problem. The tubes have 6600 hours on them so that is probably my issue but I would like to try some other things.
Thanks
Dan

I'm having the same problem with my projector, might I get take some caps off your hands, KrisRoberts?

Sure, send me a PM to remind me.

We just moved and I know they're in a box around here some place...
;-)

Any update on this repair? I just picked up a D50 and found the same issue. Haven't tried the cap replacement on the PA yet, but I'll do that soon.

I also changed the caps on the PA board to no avail

Wild Willy, can you update us on the troubleshooting you did to find the culprit?

I have no brightness control, plus severe streaking on bright objects on dark backgrounds like starfields.

Three possibilities:

-bad tubes
-bad PA board (there are other parts on the Pa board that can cause no brightness control)
-bad neck board. One bad one can affect all tubes.

Thanks Curt

I knew what type of things can cause the streaking (neck boards, tubes, etc.). I'm just trying to pinpoint the things that seem to be a trend with the D50 and losing the brightness control. Many people have mentioned the 3 caps, but not much else after that except WildWilly talking about the AC board.

From your experience, what other things on the PA board should I look at? Other caps, diode, transistor???

Do you or anybody have a parts machine hanging around so I can borrow a good PA board and maybe one neck board? If I find the culprit, I'll buy the board

Oh yeah, forgot to ask.......

Is there something wrong with your website Curt? I've been trying to get on it all day with no luck. The same thing happened a few other times, then boom it just popped up again.

Is it something on my end?

Don't even start with me about my website! If a gun could work through a tech support line, there'd be carnage at 1&1. Don't use those idiots.

I am curious though, does my site get more hits when it's up or when it's down?

I'm off camping, it's a long weekend up here, so I'll be back sometime Monday. Send me an email to curtpalme@shaw.ca and we can discuss further. I do have working boards.

Oh, and what's with these people that want a service call on a Friday afternoon of a long weekend, want to haggle over the price, saying my already discounted $150 is too high, and then admit the problem has been there for 3 days?

With happiness in my voice I told her to call someone else (she'll get at least a $175 quote). And I got out of sound installations...why you ask?

You're too funny Curt I know how you feel.

Why is it a long weekend up there? Some other Canadian holiday as a reason to drink beer and go camping?

I'll email you and wait to hear back next week. Have fun

I have an extra D50 in the attic. Same brightness problem. I had sent the PA board to Curt for repair but that did not fix the issue. If you are interested I will sell the board for what the repair cost, $200.00
Dan

Thanks for the offer Dan

What else did he fix on your PA board? I already replaced the 3 caps mentioned as usually being the problem, but that didn't seem to fix it for me either.

Someone else mentioned the HV board can cause this too. Does anyone know anything more about this possibility?

Hey Curt, how much for a full set of boards to diagnose this puppy? I'll pay shipping both ways and for the board(s) I use.

I happened to come across this thread today and see that there was no conclusion to it. The "brightnees" control problem on the PA board is NOT the 3 4700uf caps, it's the one or more of the 3 smaller 4.7uf @ 160v caps. They are C301, C302 and C303.

If you do a search, I have posted this previously. It appears that it a design defect....that as usual, Sony won't admit to.

P.S. Sony has the WORST service manuals...which I think is intentional.

Hey, thanks for the added tip I'll have to check those out when I have the chance. I just got back from the "sandbox", so I'm not doing much in terms of playing Home Theater for a bit. I'll let you how it turns out.

Curt's boards seemed to have helped improve it, but it's still noticeable in certain scenes. It did also restore the brightness control again though.

Haha, economics.

They want you to buy a new PJ every 3 years it seems

No, they just want to keep everything a secret, so they can sell you a training class where they reveal the things that they left out of the service manual.

All about the $$$ I guess.