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Old 7th Nov 2020, 1:46 am   #74
Mark1960
Heptode
 
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 638
Default Re: I found it! A very sorry looking MK14.

Try removing as much as possible and only fit the minimum to see signs of life.

You donít need 8154 or extra ram fitted. Could probably also remove the 80L95 and maybe even one of the 74ls157 and 7408. Just look for the group of 4 and 2 digits on the display.

The 8060 is not completely dead, that usually shows a single bright digit at power on.

Its sort of scanning the display, so proms may be ok.

Might be a good idea to check the data bus for any sign of being driven high and low from different sources before swapping in any other chips. Just in case you damage both sets of proms.

Turned out to be ram chip problems on mine, possibly caused by dry joints in the address decoding. Swapping high and low ram gave different behaviour and then replacing them after waiting for delivery confirmed it was the ram.
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