no H V

sparkey 65

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have a 27K7401 with intermittent HV, power supply ok (light bulb) changed u701 found 13v zener bad. all caps has been changed in horz. drive section also H O T what so crazy you can be working on it and it will come on and play for 10 min. never seen this before. HELP
 
When it's not working, does it tick?

What's your B+ while working and not working?

I'd be apt to point you towards a cold solder connection somewhere, but you may check R765 and R760. They're the entryway to the startup sequence, and if either is getting out of spec, it could cause intermittent issues...
 
no HV

modessitt thanks for the reply, B+ when not working is 17V .I,ve even injected a horz. pulse at the base the HOT it still won,t fire up, 12v supply for U701 down to 2v but nothing shorted as far as i can find.
 
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