Spectrum 2 ceramic disc rot ?

[supaduper]

I do not really buy hardware these days but could not pass up this mint Spectrum +2 which hardly has any hours on it, just replaced the tape drive belts and it is working perfectly, but I noticed on the motherboard that every 100nf ceramic disc has some sort of white rot on them with a few actually having some cracks, I will replace them but has anyone seen anything like this ?

Sinclair Spectrum2_100nfcaps.jpg (204.05 KiB) Viewed 2224 times

Sinclair Spectrum2.jpg (217.57 KiB) Viewed 2224 times

[exxos]

Maybe dust accumulation over time sticking to the tackiness of them ? does it wipe off ?

[supaduper]

No bud they are stained that way, tried isoprop but did nothing, just wondered if it was an aging thing. and some are lightly fractured so also thought it may be a heat stress thing, but surely they do not get hot.and notice the stain is in the same place on all of them

[exxos]

Could be stress I guess. A few seem to have similar "circles" of white on them. If some are cracked as well..

[exxos]

There is this post https://superuser.com/questions/1155953 ... -capacitor

The white powder is a sign of previous component failure from internal partial short circuit , over heating oozing out of molten ceramic binder, followed by slow cooling down after fusing open the internal partial shorts to allow the crystals to grow.

The external white crystals on ceramic discs are made from aluminum oxide, aluminum nitride, magnesium oxide, and silicon dioxide.

A sign of poor quality ceramic caps.

[supaduper]

Thanks bud, looks like cheap poor quality Ceramic discs , who'd have thunk it from a Mr Sugar product