I bought a Barco Graphics 800 on ebay and it is my 1st CRT projector.

I turned it on and the green tube is really bright but the other 2 are really dim. The green one also has bright diagonal lines going through it. Any ideas what may cause those problems?

Thanks.

Most probably 2SK511 transistor is gone bad in rgb amp.
http://www.lynxxx.nl/barco/troubleshooting.asp

Tom have few to sell, it's good idea to chance all three.
http://www.4000*p.dk/eviltwin/forum_posts.asp?TID=324&PN=2#top
Remove star after 4000 to get link working...

Yes, if one goes... the others are close behind.

Back when I had an 800, I developed the same problem on one of my tubes ... I measured all 3 2SK511's and one was completely shot (the one with the retrace problems), the second was 1/2 way there but nothing was showing up on screen yet, and the third wasn't perfect but wasn't great either. Replaced all 3. Should be good for another 26,000 hours. :)

Kal

Ok I got the parts replacement parts I need. Are there any other sites with more detailed instructions on how to do this?

My main concern is figuring out which screws need to be removed to get the boards out without electrocuting myself on the tubes or a capacitor.

Is it just the screws in the top of long metal bar that goes the width of the case? I have not tried to take them out yet but it looked like there might be some more screws down below there that are harder to get to.

Thanks

Not sure what you're talking about about the bar... see here for a picture of the neck boards:

http://www.curtpalme.com/Barco500_Layout12.shtm

Instructions:

(1) Locate the 3 neck boards
(2) Disconnect the wires to the neck boards
(3) Unscrew the 2 screws on each to remove them from the chassis
(4) Desolder the old 2SK511 on each
(5) Install (solder in) the new 2SK511 on each
(6) Reinstall the boards, re-attach the wires.

Just the two screws on the bar to remove the card, but there are also wires that will need to be disconnected. Of course be careful, but there is not a big chance of electrocution while removing,replacing those cards.

Ah! That bar... Vibe is right : There are only the 2 screws to undo.

xlr231: How are your soldering techniques? Are you familiar with desoldering? Reason I'm apprehensive is because you asked about electrocution... and most people with some electronics soldering experience are already familiar with the dangers (or lack thereof) to begin with so I'd caution you to not attempt desoldering/soldering these things yourself if you've never done it before. It's not difficult, but a projector like this isn't a good place to learn the techniques.

Kal

I have done a lot of soldering and desoldering. Mostly audio equipment, patch bays, and cables, stuff without huge capacitors and tubes.

The only reason I asked about electrocution is because the on the Lynxxx page with the directions they link to and tell you to read their disclaimer on high voltage circuits that will kill you about 3 or 4 times. Since the boards are right over the top of the end of the tubes I thought I would ask.

S'Ok, most of us only need to be killed once, that's enough.

:)

Let the set sit for 10 minutes after powerdown, you'll be fine. No HV to be found where you're working.

I have done a lot of soldering and desoldering. Mostly audio equipment, patch bays, and cables, stuff without huge capacitors and tubes.

The only reason I asked about electrocution is because the on the Lynxxx page with the directions they link to and tell you to read their disclaimer on high voltage circuits that will kill you about 3 or 4 times. Since the boards are right over the top of the end of the tubes I thought I would ask.
No wonder you are being cautious, you have worked with things operating at hundreds of volts and many amps.

The majority of electronics today have internal discharge methods which mean after 10 minutes they are meant to be discharged, I usually wait a day or 2 just to be sure.
;)

If you're worried about caps, you can short them with a high power resistor to discharge them. Only really a problem with really high value caps - the sort of stuff found in amps and (some) power supplies.

Kal