Greetings,

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???? This result code seems to be a common one for the 8643a.?

???? As has been pointed out, the PS is a conglomeration of COTS units, but the CLIP does have the interconnects.

???

? ?????Back in May of 2016 the 14.020122 annoyance advanced to the point where my 8643a generator became VERY flaky.?

???? It would loose PL, and simply not run reliably. The top cover was removed and the voltages measured.?

? ???The -5 was previously -4.83, but now had dropped to -4.41. ?Bootstrapping a bench supply proved that

???? restoring -5 would make the RF reliable again.

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???? The power supplies were removed and setup for testing on the bench.

???? The clear suspect was the black brick DC to DC that took in +24 and generates the -5.

???? This is on the leftmost board that filters the outputs of the two main switchers.?

????? It was powered up with a +24 V bench supply, loaded with 30 ohms, and produced 5.22 volts.?

???? The entire supply was then AC powered up, and no obvious problem could be found.

???? The instrument was partially re-assembled, and the -5 NOW is -5.18 under load.

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???? ?Go figure.? PS self test now passes and instrument powers up without the painful “calibration” cycle.

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??? ??My best guess is it was ?a contact problem given all the connectors and the removal and reinsertion cleared the fault. ???

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???? ?As of August 2019 .... it is still working fine. ?No component changes.

????

HTH as they say .....

?

Dick

Sent from?a Logic Free?Asylum deep within The?Sanctuary State?of California using?my phoneI.

Bibimus Ergo Sumus, En Vino Veritas, Quaerite et Invenietis, Illegitimi non Carborundum

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