Re: Again a 7854 power supply beast to be repaired...


Dave Hills
 

If the +130v supply is good, check the voltage on Q173's base. It should be 82vdc.
If it is low check C171 for leakage. If C171 is OK, check CR177, CR173, and Q173 for
leakage and shorts. Then check all the R's around Q173.

Dave

5) With another scope I checked the output of the Z-axys board (board A21,
diagram 13) test point TP183: the output is stuck at approx. +120V. No pulses
or other artifacts are visible. Moving the A, B or readout intensity has no
effect.

Max

Max

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