Servicing a 1966 Admiral PG919 all vacuum tube b&w television. P2/? Horizontal sweep problems
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- Опубліковано 29 вер 2024
- Trying to discover the failure of the horizontal oscillator. Some adjustment, but the frequency is way low, low enough that sweep drops out at times.
The 8FQ7 is a combination oscillator, and amplifier. The first section generates the oscillation, which is supposed to be near 15,750khz. Then the section section amplifies it and provides drive for the horizontal output stage. The 2nd stage is working .The first is only running at about 12khz. Tube substitutions are not working at all.
Lots of polystyrene caps that can fail in these circuits that can cause this symptom. Could be driften resistors. Gonna try and troubleshoot it the best possible and come to a resolution that allows it to work.
also check for any tin Whiskers in that little area where the 3 pots are encased in the metal case around them as well.
Hi you need a long set of quality test probes..
Jordan, I am a steady viewer of your channel. Your vast electronic knowledge combined with your tenacity is outstanding!
You can go down so many rabbit holes with these older TVs. Core turning with resistance like its moving??? I would have ended up tracing it to the coil and then giving up on it cursing the TV Gods. Great, deep dig and solution!
I kind of liked the four images on the screen. I think the moral of this one is believe nothing unless you see it with your own two eyes.
I've been following along, and this has been an interesting one with an unexpected ending to the horizontal. I'm honestly surprised the set works as well as it does with those Elmenco caps---I've never seen a good one yet
Oscilloscope could help... ?
Well done, Jordan! Thanks for taking time to show us how...
You keep saying .022, when it's actually .0022
Yep. Brain wants to say its one thing when its clearly another.
It's just so fascinating and inspiring to watch your work sir!