Re: [M100] M100 dead - looking for causes of low VEE
Low Vee is most likely caused by bad caps on the -5V line. The loss of -5V after a few seconds is a typical symptom as is the common problem of the LCD fading in and out over time. If you replace the -5V caps it should bring the machine back to life. I would also suggest replacing all the caps while you have the unit open. Just checked, C85 and C86 are the two to look at they may have some local corrosion near/under them which is a good visual indicator of bad caps. On 22/11/18, 10:51 PM, "M100 on behalf of Jim Anderson" wrote: >Hi, > >A couple of weeks ago my beloved M100 dropped dead in the midst of using >it (I've been keeping a journal). Suffice to say that I was already >writing about something unhappy at the time and the death of the M100 was >sort of the emotional icing on the cake. I only got as far as observing >the following before putting it aside for the night in frustration: > >- AA batteries are good (also tried with external DC input) >- Low Battery LED isn't on, and flickers as expected when I cycle the >power switch >- LCD screen is totally blank, doesn't even darken when turning contrast >knob >- Beep test in BASIC doesn't work > >I had a chance to take another stab at it tonight and lo, it worked when >I put batteries back in it, but promptly died again about ten or fifteen >seconds after powering it on. > >VDD and VB are both good, but VEE is -1.4V rather than the expected -5V. >I thought I'd post here to see if anybody has any pointers on a common >culprit for low VEE before I start digging deeper (which is a project for >another evening). I have a funny feeling I've read about someone else >having a low VEE problem, but searching the list messages turned up >nothing for me. > > > > > > > >jim >
Re: [M100] updated REX manager software, + REXNEC.
> -Original Message- > > regarding updated software, the upgrade files are posted at bitchin100 > on the REX page. > > let me know if you have any issues. I must have had more energy tonight than I thought - I also "volunteered" my daughter's M100 for the 254 upgrade, and it went off without a hitch. I didn't spend a whole lot of time with it beyond re-loading her ROM and backup images and switching between a few of them, but it all worked smoothly. jim
[M100] M100 dead - looking for causes of low VEE
Hi, A couple of weeks ago my beloved M100 dropped dead in the midst of using it (I've been keeping a journal). Suffice to say that I was already writing about something unhappy at the time and the death of the M100 was sort of the emotional icing on the cake. I only got as far as observing the following before putting it aside for the night in frustration: - AA batteries are good (also tried with external DC input) - Low Battery LED isn't on, and flickers as expected when I cycle the power switch - LCD screen is totally blank, doesn't even darken when turning contrast knob - Beep test in BASIC doesn't work I had a chance to take another stab at it tonight and lo, it worked when I put batteries back in it, but promptly died again about ten or fifteen seconds after powering it on. VDD and VB are both good, but VEE is -1.4V rather than the expected -5V. I thought I'd post here to see if anybody has any pointers on a common culprit for low VEE before I start digging deeper (which is a project for another evening). I have a funny feeling I've read about someone else having a low VEE problem, but searching the list messages turned up nothing for me. jim
Re: [M100] updated REX manager software, + REXNEC.
reposting; maybe there is a problem with embedded links. regarding updated software, the upgrade files are posted at bitchin100 on the REX page. let me know if you have any issues. cheers Steve
