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Dynaco-Doctor Forum Welcome! Need support, you got it. Or share your ideas and experiences. |
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Dynaco-Doctor Forum Welcome! Need support, you got it. Or share your ideas and experiences. |
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In Reply to: Pas 2 repair guide? posted by Cleet Torres on April 21, 2014 at 17:24:57:
This is a good example of a deficiency in the original PAS. Before doing anything else, it would be a really good idea to install a fuse. I believe the consensus is a 0.5 to 1.0 amp quick acting fuse in the PT primary.As far as where the short is, a few possibilities come to mind. Have a close look at where the wires exit the power transformer. I have one where the wires are frayed, apparently rubbing against the edges of the transformer cover. The transformer itself could be internally shorted, in any case.
The quad section capacitor could be shorted.
Otherwise, try doing spot continuity checks to ground along the B+ circuit after safely lifting a lead here and there, or trace the circuit visually looking for things that should not be touching.
You can try disconnecting the wires from the B+ to PC5 and PC6 and see what happens to the voltages on the B+ nodes to see if they are still at zero volts, which could help isolate the short. If you want to try this, use a variac to lower the AC line voltage so the B+ nodes won’t go too high with the wires disconnected.
Or, maybe just try a different 12X4...
Hope you're following safe work practices - the voltages inside the PAS are lethal.
Let us know what you find.
Edits: 04/22/14 04/23/14 04/23/14
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Follow Ups
- RE: Pas 2 repair guide? - petercapo 18:02:12 04/21/14 (0)
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