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Sony 1270 Red Tube

244 Views 3 Replies 2 Participants Last post by  Neal

After 6 years of faithful service, what appears to be the Red Tube has stopped projecting an image. To be clear, it appears to be "lit" but as I look into all three tubes, the red tube is the only one that I don't see an image. I'm sick about it and need some advice.

Thanks, Neal

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You might have a video IC problem. I have a 1270 in for repair. This problem you describe sounds like exactly like what is happening to this unit, except the one I am servicing has the problem on blue.... I am waiting on parts from Curt to repair it.

To check the board out:

Open the hood and lift the two top boards. Remove the piece of aluminum from the rear of the projector - there is a fan on each end(side) of the alluminum - it forms a sort of heat sink tunnel that air flows through. Just remove the top plate of alluminum. This will show you the 2 video boards. The board on the left does the red and green. The board on the right does blue.

SWAP the black coax video feeds going to the Red and green sections. If the problem remains with the red tube then put the coax leads back. If the problem did not move with the coax the the problem is being caused by either a bad CRT or a bad video driver board. If the problem did move with the coax, you will likely need professional assistance and/or a schematic to go further.

Next, swap the wires going to the neck boards. (I made up a small adapter cable to do this. You could also swap neck boards, but that is a bit more involved.) I suspect the problem will move when you swap neck board wires on the red/green board. Expect the green to show the problem with the wires reversed. If so - you have now confirmed the problem to be in the video board. If not, it may be "tube tyme."

If the problem is in the video board, the odds are the video amp is bad. If you are capable with soldering, swap the VPH-05 ICs around and see if the problem again moves. If so, replace the IC. Cost from Sony- aprox $125+

If you are not comfortable soldering the IC, maybe a forum member has the board for sale? If not, perhaps someone can recommend a source to you...

In any case- make sure to clean the fans and opening to the video boards. You will likely find the holes in the screen plugged up, resulting in the VPH chip overheating and its subsequent failure. Some also suggest some heatsink compound between the VPH heat sinks and the top alluminum plate. This is probably a great idea to help keep things cool...

Best of luck. Hope this helps.

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thanks for the reply. I'll take a look and see how comfortable I am with the procedure. Makes me a little nervous to be poking around in there.

I'll keep you posted.

Thanks again

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Okay, I have abit more info. Had what seemed to be a knowlegable person look and actuallu use your instructions to test the red gun. It sounds like the Video IC board VPH-05 ICS or the video driver(?). You mentioned getting the board from Sony, does anyone have a specific number to call for this part? Thanks again for the info, it was very helpful. Hopefully this will take care of the problem.

Thanks, Neal
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