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Recap M0100 mouse?

Posted by: Crutch on 2019-01-05 09:26:15 I have two Mac Pluses and two M0100 mice.  Mac plus #1 works flawlessly in every way (it has a Radius 16 and 68882 and voltages look great). But it has one weird quirk - 100% of the time I plug in Mouse A while it’s running, it spontaneously reboots (obviously I don’t need to do this ever in practice, but it worries me that it happens). Mac plus #2 never does this, and it never happens with Mouse B on either Mac.  I thought this might mean I have a low-grade analog board problem to fix eventually with Mac plus #1, but today I decided to pop open my mice. Mouse #1 was made in Japan and I believe is a 1984 vintage (two bottom screws). Mouse #2 is made in the USA and has one bottom screw, which I believe means it’s a slightly later model. Anyway, Mouse #1 (brown board in photo) has two 47uF electrolytic caps inside so I tested them in-circuit with my ESR meter. It didn’t like them much (said “good if under 47uF”, in fact, which sounds like a pretty marginally result for a 47uF cap). Mouse #2 has no electrolytic caps.  Anyway so I’m wondering - is it possible I have failing caps and need to recap this mouse? I haven’t heard of anyone recapping a mouse and might feel slightly silly doing it but I don’t see why not. (I hesitate only because it works otherwise and in particular Mac plus #2 seems fine with it.) Visually the caps look OK. Anyway, curious if anyone has seen this problem before and if I’m on the wrong path and should start poking around the analog board instead.

Posted by: Crutch on 2019-01-05 10:16:28 (By the way - this happened before I installed the Radius board also, so that’s not a factor.)

Posted by: LaPorta on 2019-01-05 11:46:50 All I'd say is: why not? Just do it and see if it helps.

Posted by: Crutch on 2019-01-13 06:48:33 Thanks.  Well, I recapped the mouse.  Once I got them out of the circuit I tested those with my meter and they were completely fine (so much for the fancy ESR checker) but I replaced them anyway with nice new ceramic caps.  Unsurprisingly, it made no difference (though I am going to gloat about my state-of-the art recapped mouse, now 🙂)  ).  I also noticed Mac plus #1's CRT can show small white screen flickers when I smack the front or side of the case.  Analog board solder joins getting cracks, maybe, and causing both issues?  I'll try touching up those when I have time.

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