Quote:
Originally Posted by ctc17
Try unplugging the crt socket. Maybe its a problem with the horz blanking if you noticed problems with the other boards. It doesnt take much to overdrive the crt and pull the hv down to nothing. I doubt thats it but its an easy check.
Its amazing how dificult some of these hv problems can be to sort out. There must have been times when shops really lost money on repairs.
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Pulling the CRT socket was one of the first things I tried.....
I ohmed out the fly this weekend and it checked GREAT maybe better than the tests I did before I got it working the first time. The focus coil....not so much all three of it's windings should measure ~35.5ohms, but two came in at 17.5.
I was able to make it so that the HV drops when the yoke is disconnected by disconnecting the lead from the focus coil to the damper (and a couple of other things on that line), but the max HV was only about 10KV. I was getting 11KV before that without the yoke and about 7-8 with the yoke. Connecting the HV reg cap drags the voltage I'm getting down some even with only 11KV to start with.
The drive looks good, but the entire wave form is negative (even the peaks are below 0V) on my scope when switched to DC mode. Also sam's calls for 150V signal and I only get slightly less than 100VP-P. Could this be what is causing weak HV?
I can post the drive wave forms and some fly pics later when I have time.....Man, have I ever been busy lately!