Hi, About one year ago my two "good" M100 stopped working almost at the same time. I haven't got any time to look into them yet, but I really miss taking notes on a M100 so I'm trying to get them working again.
The first one kind of works but the contrast is ridiculously low, and you can only see anything if you look almost perpendicular to the screen with contrast dial to the maximum. I had a look at the Service Manual, and find out the issue is probably caused by Vee being at -2.4V instead of -5V. The same service manual says to check D15, C85 and D14. That's where I'm starting to be out of my comfort zone... My multimeter has a diode testing function, and I definitely get suspicious reading of D14 and D15: For D14 I get 0.1V in both directions (black lead on the cathode, or black lead on the anode) and for D15 I read 0V in both directions too. On my second M100 (which has another issue but the contrast and Vee are fine) I read respectively 0.5V and 1.4V for D14, and 0V and 1.5V for D15. I don't know how to check C85, but having recaped the second M100 a couple years ago I have some spare left so I suppose I can just change it if fixing D14 and D15 desn't work. At this point I think (tell me if I'm wrong :o) ) that the next step is replacing D14 and D15, but I wasn't able to find the exact same reference listed in the service manual. Is there an unofficial list of available modern parts for the M100 somewhere? Here are the closest things I have found so far. Could someone tell me if they have a chance to work? (or recommend a known working alternative?) D14 is listed as "DIODE, SILICON, ZENER, RD5.1 EL1 (QDZ5R1EL1A)" and I found some "Fairchild BZX79C5V1 5.1v Zener Diode" ( https://www.ebay.com.au/itm/Fairchild-BZX79C5V1-5-1v-Zener-Diode-x-10-/164107867434 ) D15 is listed as "DIODE, SILICON, 1S2076 (QDSS2076#B)" and I found "1S2076A HIGH SPEED SWITCHING DIODE DO35" ( https://www.ebay.com.au/itm/50pcs-1S2076A-HIGH-SPEED-SWITCHING-DIODE-DO35-/252644110156 ) Thanks! Eric
