I just picked one up last monday at an estate sale. New, in the box, but
opened. lack of ANY fingerprints, wear etc leads me to believe got it, looked
at it, lost interest fast.
I put in 4 new AA batteries...no joy. I have the new manual, and I found the
service manual online and poured thru it.
So here we go: TRS80 M100 serial 306005812
Have not opened it yet.
I would assume the nicad is long dead and is likely 'reaction complete' meaning
it has no chance of charging. I did not get the power supply (nor was I
looking for one at the auction, but part 2 is this monday so I will)
I have ample power supplies I can rig up.
I note it says tip negative - common to RS equipment - whereas the rest of the
planet preferred tip positive. But again, I can dream up the correct polarity.
I suspect due to age and perhaps accidental power reversal, the oscillator used
to produce the board +/- DC could be faulty, and I have the proper tools to
probe it and test it.
>From looking at the SCM, if it was reversed polarity, small chance this
>translates to the chipset as the PS/battery box is isolated thru the
>transformer and reversal would have reverse biased the transistors. perhaps
>dried caps on the timing circuit? dunno yet.
When I turn if off, for a small half second the low batt light flashes, but
that light is driven from a narrow voltage divider and would be expected. A
couple times on power on if I press many keys, I get beeps from keys. faulty
virgin display?
Any ideas where to start?
thanks!
