I have a strange problem which I've encountered once before but didn't find the cause for.
I have just installed a new green P19 9" Marquee tube into a Barco 1209/2 and have performed the neckboard mod required.
I had some problems with using the wrong silicon on the boot when I installed a HV-lead which caused the green to arc, but I resiliconed it and that fixed that.

My new problem is that no matter what I do I can't get the green to not drown the other colors. I was afraid of this since it probably has heaps more emission than the other two tubes.

I tried adjusting the pot on top of the neckboard and used a jumper to shortcircuit it while adjusting the regular G2. Still no dice.

Not sure but this may be related to the problem with the red tube.
I'm thinking that there was a bad connection to ground on the red tube at one point which may have damaged the tube?
No matter what I do now I can't get enough output form the red. If I turn the g2 up or the gain or cutoff all I get is a film in front of the red raster as if it being over driven.
Could bad grounding cause this or is it likely something else? I swapped neckboards and that didn't help either.
The blue tube is working great though.

I've had this problem on a BG808s once too. All of those tubes weremint and with about the same output. Still the red wouldn't get enough output without that film appearing on the raster screwing the picture up.

Any clues?

Well... I solved it temporarily...

Don't know what caused it but for some reason the blue ended up where the red was supposed to be and the red where the blue was only fainter
So what I did to remedy the problem was to swap the red and the blue cable. Then I used an vga interface and boosted the red and lowered the green a little and that solved it.
Not a pretty solution but it did the trick.

The thing is this was an SEOS 1209 originally which I converted into BG1209/2 and then the SEOS vertical module ended up needing to be replaced.
So I put i a non SEOS vertical module and maybe this was what caused this strange phenomenon?

This was really a last resort but it seemed like a far more attractive alternative than to take the damn thing down from the ceiling and change the red tube which I thought was defective.

But I sure would like to know what caused this problem. All the connectors from the tubes went into their respective positions and no pins were bent so everything was connected in the right way but still the same problem.

The BSX-20 final driver transistor fails on higher hour barco 12xx chassis.

After doing a millon mods when testing the neck cards I have noticed that inside the metal case of the 12xx neck cards gets really hot espically on the left side of upper case.

The BSX-20 driver transistor does not fail but the gain gets week. Causing the picture to be ok but that color will be week.

I recommend to replace this upper left transistor with a new one and it will really brighten up the tube.

Email me I can just give you some I have a box full of them.

Greg

Oh, but I believe I had the same weak output on the red with the neckboard form the blue swapped over.
Shouldn't the faulty neckbaord display the same phenomenon on the blue as well then?
And that doesn't explain why swapping over the cabled at the back of the projector made the problem go away?


But you are right it does get very hot. I'll be glad to give it a shot though.


Sounds great.
You've got mail. ;)