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Old 10-31-2021, 04:39 PM   #6
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Join Date: Jun 2012
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Default Re: Motor control board

It's nice top know one is getting warm, it would be nicer to know WHICH ONE? I will guess and say the +15 is getting warm and the -15 is not.
If both components have the same numbers it is unlikely they are both positive and negative voltage regulators

Do both regulator ic's have a common ground? have you checked the IN on the -15 ic to see if it has any voltage?
The transformer secondary is likely center tapped and the center tap goes to ground, and one part of the winding supplies each ~ on the bridge rectifier, then the + of the bridge supplies the positive IN for the +15v regulator and the - of the bridge supplies the negative IN of the -15 volt regulator

Last edited by R_J; 10-31-2021 at 04:53 PM..
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