Hey all,
I just wanted to follow-up my post yesterday with my fix for my
Amplifone HV problems...
So I start probing around the HV board, and find that the +24V is
there, but no -24V. I trace back, and there isn't even any -32V, or
whatever the corresponding input is supposed to be. I checked both sides
of W1, and found -32V on one side, and 0V on the other. Damn crappy
jumpers!
After replacing W1 with a wire, I fired everything back up, and
the 2 5A fuses glowed birghtly for the couple of seconds before they blew.
I checked and found a short (big surprise, huh...) I pulled out the new
7924 I had put in, and the short went away. Replacing the 7924 and 2
5A fuses got me a picture, although it was badly out of focus. I was sure
that the wire to the focus divider from the HV transformer was OK, since I
had just soldered it the day before, but the wire on the other side of the
focus pot had broken. I resoldered it, and I got a nice
picture....except, it looks like the purity/convergence/whatever is off
(There is a red "shadow" around all text, for instance.) I'll get around
to fixing that whenever....
Thanks to all who helped me out with that!
Joe
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Joseph J. Welser
Design Engineer -- Crystal Semiconductor Corporation
Ph.D. Student in E.E. -- University of Texas at Austin
Work:
P.O. Box 17847; Austin, TX 78760
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