'75 CB 750 died while cranking, now no power

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bossboy302

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Was cranking over engine with fresh and fully charged battery. Was cranking great, then a "pop", then nothing-electrically dead. The "pop" sound came from the electrical area and was easy to hear since seat and side covers were off. With VOM I tested battery voltage at 12.7v. I checked main fuse-fine. Then this morning, when I turn the key on, the warning lights show a very faint glow, becoming slightly brighter, but still nothing else.
With VOM and wiring diagram I'll start tracing.
Meantime, if anyone can shed light, I'd appreciate it. My first guess is rectifier. Just a guess. Thx
 
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brettp

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Check negative connection to frame and make sure battery positive isn't grounding out before it gets to the starter solenoid.
 
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bossboy302

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I think the solenoid may be bad. The 12v circuit flows fairly far (not finished tracing yet), but already I have had a duplication of the original problem. Just taking connectors apart and cleaning then reassembling, I was able to get all the power back on. The warning lights glowed bright and steady. Then I hit the start button-pop-dead. Just as the first time. I was listening for it this time-definitely the solenoid. So maybe.....
 
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brettp

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bossboy302 said:
I think the solenoid may be bad. The 12v circuit flows fairly far (not finished tracing yet), but already I have had a duplication of the original problem. Just taking connectors apart and cleaning then reassembling, I was able to get all the power back on. The warning lights glowed bright and steady. Then I hit the start button-pop-dead. Just as the first time. I was listening for it this time-definitely the solenoid. So maybe.....
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Open the starter switch and give it a cleaning. I would also check the wire connection at the starter motor. The pop seems to happen when hitting that starter button so trace that circuit.
 
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bossboy302

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Will do...am systematically following the wiring, have proved out the solenoid and starter motor (by bypassing ion switch and start button)
More to follow today,,,thx.
 
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