Chromacolor II Focusing problems

[jpdylon]

Hello all. I have a 75 Chromacolor II 25" console (i forget the chassis #) When its first powered up its fine, but after 30 minutes or so, the focus starts to drift. Within another half an hour the picture is a complete blur.

I don't have an HV probe for my Fluke, so I can't check focus voltages. The control has run out of rotation, and doesn't seem to do anything at all after the problem has fully reared its blurry head.

If anyone has an idea of where I can start, I would most appreciate it. This has been a faithful set that had a wonderful picture. There's no way I want to dicth it if I don't have to.

Thanks to all,
Jordan