sounds quite typical for a dried out electrolytic cap. Look for the unregulated -10V that goes into the regulator circuit. Most likely C3 on the power supply motherboard is dead.
Adrian Mark C. Stephens schrieb:
Checked the PSU voltages on the PSU card next to the 10811. The -5.2 is reading -4.2. Took a look with the scope and instead of a nice flat DC I see a 4V Peak to Peak spike @ 100Hz. Trying to track down a service manual. Any ideas on this one guys, if the Pass tranny was shorted, it would be a lot more than 4.2V unless the overvoltage Zener is able to sink all that current... -marki -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Saturday, 6 July 2013 8:18 PM To: time-nuts@febo.com Subject: [time-nuts] HP 5370B Leds pulsing slowly, buttons selecting normally, PB LEDS scannning and appears to be reading o/k I went to use my 5370B todayt and noticed the LEDS on the display are slowly sort of pulsing bright one after another. Also all the push button LEDS are going on and off one by one. The strangest thing is that it appears to be working o/k via HPIB. I don't have extender boards but I do have a signature analyser. Could it be something silly like one of the PSU regulator has gone kaput? Has anyone seen this issue before? -marki _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
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