The M100 can be a bit difficult to recap as it does not sue thermal reliefs on 
the pads which go into large areas of copper. This can make it hard to get the 
joint hot enough to melt the solder but not so hot as to lift a pad. There are 
also a few areas in the power supply section which tend to get eaten away by 
leaking caps even though it may not look like there is a problem. Replacing the 
caps can exacerbate this problem by causing a very marginal connection to go 
open.

I would first check the test points on the board for 5V, -5V and Vbatt. I would 
guess you are missing one of the 5V rails. Then find the test points on the 
schematic and trace each signal back toward the transformer to find out where 
the open circuit is.

Jeff Birt


-----Original Message-----
From: M100 <[email protected]> On Behalf Of Hiraghm
Sent: Sunday, December 25, 2022 1:06 PM
To: [email protected]
Subject: [M100] I mortally wounded my Model T

So I decided to try recapping one of my two Model 100s.

The ones I replaced all looked okay, no sign of leakage; I replaced the batter 
which did have some corrosion on it.

I used a Model 100 recap kit, but as the voltages didn't match on some of the 
caps, I decided not to replace those.

Like a dummy, I forgot to fire it up and test it before recapping it; it had 
been working when I put it in the closet... over  a year ago.


I made sure all the polar caps were oriented correctly.

I put it back together, turned it on... nothing.

I flipped the memory switch on the back to "on"... turned the machine on 
and still nothing. Tried the contrast knob, no good. Tried reseating and 
wiggling the batteries (I don't have a power adapter)... nothing. But 
when I turned it off with the memory switch to on... the batt low light 
flashes briefly.


So I killed my backup M100 :(

I'm not very experienced with a multimeter, but can anyone offer an 
suggestions for troubleshooting how I killed it? What may be likely 
causes for its current dead condition? Where to start looking?





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