Thanks for the encouragement. I'm going in. I found test points on the power supply/motor driver board as detailed in Chapter 12 of that manual.
+5v, +12v, +15v, +42v and +85v are all there (and all .4v high or so) But there is no -12v. That seems relevant. The capacitors all look OK to the naked eye. Actually diagnosing and repairing electronics is new territory for me, but I suppose this is where I read up, maybe pull that board out, and start testing diodes and caps. Thanks again Alexandre - and if you or anyone else has any clues to narrow it down, please share. M. On Fri, Nov 11, 2016 at 3:38 PM, Alexandre Souza < alexandre.tabaj...@gmail.com> wrote: > How is the power supply? All rails ok? Input/output capacitors not bulged > nor leaked? > > 2016-11-11 21:36 GMT-02:00 Michael Newton <michael.new...@gmail.com>: > > > I acquired a working HP Draftmaster RX (HP part # 7596B). > > > > An awesome machine, 36" roll feed and 8 pens, complete with several pen > > carousels, user manual, and hundreds of working pens. > > > > I was very excited to make a splash in the art world with this thing. I > did > > get it to perfectly draw a 3 color demo page from the front panel. > > > > Thereafter it started displaying errors on the display such as "200" > which > > means it needs "mechanical calibration". > > > > Thanks to hpmuseum.net I acquired the service manual > > <http://www.hpmuseum.net/document.php?hwfile=1292>, which catalogs many > > calibrations and self-tests to run from the front panel, including the > > aforementioned "mechanical calibration". > > > > So I power up with the appropriate front panel keys depressed to run this > > calibration. The paper drive motor starts making noise, but the paper > > rollers aren't turning, and the LCD display is blank. > > > > Since that moment, the LCD display is always blank so it is currently a > > boat anchor. > > > > It's a terribly sad state of affairs. I have basic electronics and > > mechanical skills and an oscilloscope so following the troubleshooting > > procedures in the manual I might be able to identify a part to replace. > But > > of course, parts for sale online are are rare, expensive, used and > probably > > untested. > > > > Probably better would be lower-level repair of whatever parts are faulty > > but that's probably more than I can manage at my skill level. > > > > I'm in Seattle, WA. Is there anyone alive in the pacific NW who will pay > a > > visit and help me fix this thing? (The only company I found that admits > to > > working on pen plotters is 360tech in Austin, TX.) > > > > Or someone elsewhere I could ship electronics parts to for test and > repair? > > Or provide guidance, or help in any form at all? > > > > thanks > > M. > > >
