[Fwd: Re: [sebhc] IC information]
Dwight K. Elvey
dwight.elvey at amd.com
Mon Mar 21 11:54:18 CST 2005
>From: "Glyn Firth" <glynf1 at cox.net>
>I replaced the regulator, all the voltages to the 8080A are correct. But
>the old H8 will not boot up. I feel that the Rom ( IC 204) was fried
>also. Any ideas?
You might try checking to make sure that the clocks
are workking. I've had a number of failures of 8224 chips.
I've also found that a bad RAM card will stop the boot
as well. Try removing all but one RAM card ( if you have
several ) and configure the address for the begining
of RAM memory ( forgot the address ).
Both ends of memory need to work. The boot code will
set the stack to the end of the memory found and it will
put variable and vectors into the low memory. This means
both the top and bottom memory need to work. Often if
you have several RAM cards, you can find one that is
It could be the ROM as well but this is rare cmpared
to other problems.
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