Thread: Zenith 2250R
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Old 09-13-2018, 06:01 PM
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Zsuttle Zsuttle is offline
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Quote:
Originally Posted by Electronic M View Post
7.5KV should be enough to get some kind of light on a healthy 12" CRT...Try pulling the Vert output tube and see if you can get a horizontal line on screen. Is the ion trap of the CRT adjusted correctly, and do the electron gun bias voltages look reasonable?

One thing to be wary of is that if the horizontal oscillator is not running very close to the correct frequency the HV can become low (yet all the DC voltages on the output tube can be about right). If you haven't adjusted the horizontal osc with a scope and a frequency reference (the sync pulses on the composite video output of your signal source is a good reference), and you have never got video on the screen then the osc is likely to be off freq a ways.
That explains a few things, the horizontal oscillator was at 15.35khz instead of 15.75khz listed on the service manual. This might be a stupid question but what exactly gets adjusted? Do I adjust the master oscillator? Or is there an individual adjustment for the horizontal oscillator?

Sorry for all of the questions, still a newbie at this
~Zach
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