Defeated by a Commodore 1950 Monitor

Mark J. Blair nf6x at
Tue Dec 2 16:54:30 CST 2014

> On Dec 2, 2014, at 14:46 , Brent Hilpert <hilpert at> wrote:
> If, for example, Q402, R414 or R413 failed open there would be no current supply for the V coil. You said you were getting some variation with the V centering, so, yes, the problem may well be elsewhere.

That's about what I was thinking. The horizontal line is near the center of the screen, and can be moved up and down with the centering control. If just one side of the H bridge was broken, then I'd expect to see a badly distorted raster on one half of the screen. So, that's why I suspect that the ramp isn't getting generated. I'll do some more poking around to see if any signal is being fed to IC402 by IC401.

Mark J. Blair, NF6X <nf6x at>

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