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Old 10-29-2011, 11:54 AM
old_coot88 old_coot88 is offline
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Quote:
Originally Posted by madmike17 View Post
Turns out, the truck is positive ground. with the transformer disconnected, I read 307 volts dc to ground.
Now that's with C34 still in-circuit, right? And you're getting 307V positive to ground across C34?
Quote:
When I reconnected the circuit, the vibrator didnt even run.
Sounds like something's shorted out on the B+ line, like maybe filter cap C29. Did you replace it after it 'spilled its guts' from reversed polarity?
Quote:
After a lot of fooling around with it it finally began to run. Unfortunately, the radio does not work. A hum the same frequency as the vibrator came through the speaker, but nothing else. As i turned the tuning cap, there were crackles and pops from the cap itself. It sounded like high voltage arcing between the plates. Should the rotors have hv on them?
The tuning cap shouldn't have any signifigant voltage on it, maybe just a few volts max.
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I know the stator is directly connected to ground.
Normally the tuning cap rotors are at ground and the stators are the 'hot' side of the cap (unless you've a got a very unusual style of tuning cap).
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The vibrator really didnt want to start, I had to tap on it and shake it to make it start. I think I am in over my head. Now what?
You might try disconnecting what you did before, leaving just C34 in-circuit, and see if the vib will start up easily. If so, it suggests a heavy short in something 'downstream' (like in C29) lugging the supply down and stalling the vib.
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