Quote:
Originally Posted by Eric H
If both vert and horiz stability are bad, and the caps have been replaced, I'd look for a drifted or open resistor in the sync separator circuit.
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I think I figured this one out actually. Turns out the tuning and fine tuning on the same shaft were frozen solid together and didn't even realize there were two. Was finally able to work it free and with the fine tuning dialed in the lock is solid both ways. Now of course, sound is best when tuned away from best picture, but that seems like more of an alignment issue -- problem for another day!
I was noticing the certain voltages were still low, such as the CRT screens and the boost voltage was about 520V where it should be 580. Checking the schematic again I realized there were two caps that I didn't mark as replaced which turned out were in the HV cage (duh). I carefully took it all apart, replaced the caps and carefully put it back together and.... no HV. Took it all the way apart again, triple checked the wiring and joints, carefully put it all back together and... still no HV. Verified DC resistance all the way across the flyback, resistance between the grid caps of horiz output and HV rect were both spot on schematic. Ultimately, it appears that in the jostling around, the filament of the HV rect decided to go open - no continuity between pins 2 and 7. Tried touching up the pins, removed the base and tested directly at the leads, but still open. Unfortunately this is the only tube I do not have a spare of, so at a small pause.
Before all of this I did experiment with the brightener and it did make a difference in terms of overall brightness however the contrast was still very washed out. As in, adjusting brightness/contrast it went from dim gray on gray to saturated white on white. Possible if the caps I did replace could have been causing this? (attaching snippet of schematic)
Thx all!
FK