Re: 2710 mpu lockup on start. Help!!


On Wed, Dec 2, 2020 at 11:53 PM, Stephen Bell wrote:

A failing EPROM can be very sensitive to the supply voltage being a bit low.

You can check this with one of the better EPROM programmers that has voltage
marginning to verify the data. Read in the data at nominal 5V Vcc and
re-verify the data at Vcc +/- 10%
Many (early) devices have a Vcc spec of 5V +/- 5% (like standard TTL, Intel 2732 etc.), so 4.78V is marginal in any case. Also, It's low for a +5V nominal power supply.
I'd really check that.


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