Check your work young student! Good advice for every restoration and I should have done it sooner. I traced every wire on every connection that I had my hands on and three hours later I'm vindicated but sad to report that I have not found a single wire/connection out of place.
I tried a few taps on each tube and no changes there. Maybe I can retest the tubes for HK shorts.
Quote:
Originally Posted by old_coot88
So.. it kinda looks like the hum is arising somewhere in the video chain 'upstream' of the CRT. And since the sync is affected too, the hum must be occuring upstream of the sync take off point. (Just guessing, but the sync may be picked off at the vid. output which was common practice in the old stuff.)...
If it ain't a tube, maybe you could post a pic showing the video amp and sync areas of the schematic.
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It looks like the sync is taken off of the plate of the 2nd video amplifier. The video at this point carries the sync pulses with it to the sync amplifier which would magnify these signals. The sync separator would remove the sync pulses from the video (or does the term "separate" come from separating the horizontal pulses from the vertical?) and pass them on to the vertical and horizontal output sections. If this is correct and the problem is originating in the video section, is there a way to isolate every thing upstream from the 6SN7 sync amp/separator to quickly confirm this? Would removing the video amplifier tube achieve this?
I could be completely off base on my thoughts above but just trying to think it out as much as I can on my own so I can learn.
