This was what most concerned me about the #MacintoshPlus.
I removed the obviously worst candidate, and found this. Seems the ultrasonic didn't want to go there, at least on the first try.
(Also, I removed the cap with the leakage just above it. It tests wildly off spec so I've ordered some replacements for all of them on the board.)
Rubbing with deoxit and IPA has got rid of most of it. Probably need to give it another go before adding the package back on (and definitely more work on that itself first).
This filter is seemingly for the printer port, so if it's the only one like this, it's not such a huge loss. I am expecting those filter packages to be *very* hard to source if they don't work.
(But if you can provide some, reach out!)
Soaked the board in deoxit and left it for the night. Revisit tomorrow.
D'oh 😭
Seems this was rusted through. I'd hoped to remove it, scrub the rust and perhaps then replace it, as although it's just a 0.1uF bypass cap, these types look rather distinctive - and a new one will look out of place.
I did manage to remove the only other one with rust damage completely intact, and it measures okay - but tbh now this one broke, I'll probably replace them both. Oh well.
@retrotechtive There's a person on a discord server I spend a lot of time on that has a fair collection of these "SMT Cap in a glass tube" caps. I could reach out if you want to try to keep it looking original.
@yestergearpc thanks, that would be great if they have some that match! They're 0.1uF in value.