Re: 7104 SMPS no start troubleshooting


Bob Koller <testtech@...>
 

Most, if not all, of the boards have "harmonica connectors" for the supply input. When I am faced with this, I connect the ohmmeter at the PSU perhaps, and, noting the resistance, remove the connectors one-by-one, checking to see if the resistance reading jumps up a bit. If it does, you have likely found the board with the shorted cap. From there it is usually a simple matter to check the resistance across the caps on the board.
It usually is about this simple, especially on the 7000 series. It is also possible that the short is in the PSU proper, again, disconnecting it from the main scope should reveal the location.

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