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Old 11-01-2021, 01:55 PM   #14
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Default Re: Motor control board

Originally Posted by redwire View Post
Either the -15V rail has wimped out and collapsed, or something is overloading the -15V regulator. It's not good for IC's and semi's power if a -ve rail goes +ve. I would put a reverse diode from each of the two rails to GND, to keep working on this.

The two VREG's look like on the main board two big heatsinks, the IC's are TOP-3 packaged, one says G/IN/OUT.
The second board has a bunch of dual diodes and transistors, I don't see a voltage regulator in the line up.
Another possibility is the +15v is shorted with the -15v rail somewhere.
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