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Old 03-09-2019, 09:35 PM
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Electronic M Electronic M is offline
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Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
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Quote:
Originally Posted by mrjukebox160 View Post
You DID notice the brown cap with the crack in it hooked to the boost diode as well right?
Yeah, that maroon drop C140? does indeed look damaged. Don't discount those maroon drops as being reliable...While some are still doing okay several have reported finding them drifting in value or even leaking (I've certainly found at least one leaking current)...

Here is a possible cause of that resistor failing: C140 started leaking current badly overloading the boost rect diode causing it to short, the rect then passed ~1KV AC pulses to the boost line. The boost is resistively connected to the 400V B+ rail and on negative 1KV swings of the horizontal feeding the shorted boost diode it started passing too much current through that 100K resistor frying it. Should be easy to check by ohming out the rect in both directions and testing that cap.
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