PET 6540 ROM operating temperature

John Robertson pinball at
Wed Nov 19 23:39:33 CST 2014

On 11/19/2014, 5:47 PM, Josh Dersch wrote:
> 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?
> Thanks,
> Josh
A fan is a good idea on older electronics. the cooler they run the 
longer they last. A heat sink epoxied to the top of hot ceramic devices 
is not bad either...

John :-#)#

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Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
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