HP Forum Archive 03

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hp-22 Message #1 Posted by Alex on 22 June 2000, 11:17 p.m. Hello all,I have a hp-22 that has been badly damaged. I was wondering if a schematic available for it- or pin out of the ic's on the board. I compared the 22 vs a working 25 nad the 22 doesn't seem to have -12 volts. Any help would be appreciated. Thank's in advanced

Re: hp-22 Message #2 Posted by Viktor Toth on 23 June 2000, 4:11 a.m., in response to message #1 by Alex Alex, I'm not aware of the existence of an HP-22 schematic (certainly not the chip pinouts; they're all proprietary; how, does anyone have an original HP Service Manual for Woodstocks?) But at least in one case, repairing an HP-25 with a problem similar to yours was surprisingly easy. The cause turned out to be one broken diode in the DC-DC converter; once this was replaced, all voltages were present and the machine was working properly. Viktor

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