Thanks to all your precious advises! After posting my message yesterday, I've read the service manual cover to cover (I wish I could understand everything they say in there :o) ) and tried to measure the different voltages recommended in both your emails and the service manual. I noticed the flickering of the first line which was very hard to notice yesterday was sometime a lot more noticeable... especially when my finger was on the power switch. During the flashing, the Date was displayed correctly so I tried pressing Enter at the right time, and I was able to enter Basic... Except the cursor was missing and the unit was frozen again.
I measured a few more voltages, and tried again the Enter key, and it worked. Even better, after coming back to the menu everything was still working. So in short I'm not sure why but it's working again. The only odd thing I noticed is that the voltage at the NiCd battery is still 4.37V instead of the 3.7 it should be; it's the same not matter if power is ON or OFF. Here are a few replies to the comments you guys sent me: VDD and VEE were respectively 5.06 and -4.62V I'm not sure -4.62 can qualify as a "strong -5V" but I'm really out of my experience zone here. I also measured the VB test point at 3.95V when power is OFF and 5.04V when power is ON, which sounds correct according to the service manual. I found the Jeff Birt video (he posted the link a few days ago (thanks Jeff)) and the spreadsheet with all the caps. I'll try to order them since soon or later I'll have to change a few of them (note: the spreadsheet is linked in the description of the part 2 of the video) : Part 1: https://www.youtube.com/watch?v=hbLWk7ir9sI Part 2: https://www.youtube.com/watch?v=IGTdNMx1V1w The RTC chip soldering seems OK but again I'm not an expert here. When I said the keyboard wasn't working, I meant it wasn't responsive. I think the problem was that the unit was more or less crashed and so the keyboard wasn't scanned/processed (also the "CTRL + Break + Reset" combo did work. I think I'll try to change the NiCad as planned and perhaps the caps, clean the PCB with alcohol and see how it goes, but I start wondering if I shouldn't try buying one (or more) other M100, just in case... Would anyone here have by chance a spare unit for sale? ;o) Eric
