Every single Model 100 in the entire world needs the following maintenance:
  * memory nicad replaced (modern NiMH is fine)
  * Complete replacement of all electrolytic caps (complete recap) with
proper cleanup of leakage and corroded joints/traces
  * Bath in ~100% IPA and scrubbing to remove factory flux residue

Without these things, your M100 is dying rapidly. These are 100% must-do
repairs to all M100s now. I cannot stress this enough.

-Josh

On Tue, Sep 23, 2025 at 11:30 PM Erik Keever <[email protected]> wrote:

> Internal NiCad for sure.
>
> It's also possible/probable that the electrolytic caps are failing.
> Multiple caps in mine (the 1uF ones - the smallest) had failed and peed
> acid onto the circuit board when I came back to it after many moons. It was
> bad enough to sever the trace that brought the LCD bias to the display,
> resulting in a zero-contrast condition. At this point those electrolytics
> are 40 years old so recap is an excellent idea.
>
> On a tangent about the caps... the march of Progress has brought solid
> state MLCCs within easy reach of all the capacitances up to about 1uF. Just
> saying, MLCCs age far more gracefully (they DO age though, the high K
> dielectrics undergo a phase change that's reset by soldering temps), and an
> 0805 is just the right size to fit across two .1" thru hole pads...
>
> -- Erik
>
> On Tue, Sep 23, 2025, 6:53 PM John R. Hogerhuis <[email protected]> wrote:
>
>> Yeah if it hasn't been replaced it's probably the internal nicad.
>>
>> They all need to be replaced at this point.
>>
>> -- John.
>>
>

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