PET 6540 ROM operating temperature

Josh Dersch derschjo at
Wed Nov 19 19:47:55 CST 2014

Hey all --

A quick one -- what's the normal operating temperature for the old MPS6540
ROMs used in the original Commodore PETs?  I noticed last night after
running mine for ~30 minutes that the ROMs were very hot, to the point of
being painful to touch.

The machine is running fine as far as I can tell -- though I haven't
verified the contents of the ROMs, BASIC runs without any apparent issues.
Voltages are normal (just a shade under 5V).

I've not experienced ROM chips that run so very hot -- is this normal?


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