Reviving a Power Macintosh 7500/100

[Phipli]

The board that I photographed is the one that I purchased on eBay. I'm thinking that the melted adhesive may be a sign of overheating of the processor. I think I should ask for a refund before it's too late. I assume from prior posts that the 180MHz core clocking would not be the root of the failure that I am seeing.

I meant the 180MHz specification is on the FCC sticker and the CPU.

Don't forget to gently clean the CPU and heatsink with IPA and a cotton bud, then apply a very small amount of new thermal paste.

I don't think there is anything likely to be wrong with this CPU.

 

[Byrd]

I don’t know what that black adhesive but not normally placed. Just make sure it’s not conductive and once you know the Mac works it might come off/dissolve with IPA or Acetone. Or just leave it.

 

[Phipli]

I don’t know what that black adhesive but not normally placed. Just make sure it’s not conductive and once you know the Mac works it might come off/dissolve with IPA or Acetone. Or just leave it.

It's a rubber foot that has degraded. Possibly badly made rubber that wasn't properly manufactured.

I've seen it with a couple of things. It can also be cause by wrapping good rubber in a plastic with too much free *mumble mumbe mumbe" that is offgassing *mumble* that changes the properties of the rubber.

Think how some expanded polystyrene packing melts power cables when stored long term? Not sure if you've seen that. But it's the same thing.

Sorry I can't remember the technical details. I asked a materials scientist at my old job once, but remember the shape and not the details of the answer.

Edit : I don't expect it is conductive, so I would probably just clean it for aesthetics and to stop it getting on everything, but wouldn't be too worried about it causing harm.

Oh, but probably best to not let it get on plastics. Just in case.