EPROM issues, who can burn? - test-drb@ccmp.vtda.org

1 Nov 1999

I agree, mostly, with what you've said here, Tony.  The easy fix, in many
cases will be to program the code into several larger but readily available
and easily programmed parts, then wire an adapter from the target board's
socket to the physical EPROM on the board on which the EPROM resides, with a
pair of appropriately sized IDC ribbon cable headers crimped on the ends of
the cable.  That should work, even if you have to hang the adapter board
...
 from a hanger in the rack.  Packaging problems are what
the REAL engineers work hardest at, while the youngsters conjure up the fancy
circuits.  This
is mostly a packaging problem.  The higher speeds of today's common and
cheap parts will compensate for the few nanoseconds lost in cables, even if
some form of termination has to be introduced.

Dick
-----Original Message-----
From: Tony Duell &lt;ard(a)p850ug1.demon.co.uk&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Monday, November 01, 1999 1:50 PM
Subject: Re: EPROM issues, who can burn?

...
   Thats simple,
if emulation will make you happy, why stop at the eproms,
 just run one of the emulators for the whole system on your PC. My goal is 
Oh, come on, there's a heck of a difference between replacing an EPROM
with a more modern (and larger) one containing the same code and running
an emulator for the entire machine on a PC. Well, certainly to a hardware
hacker there's a difference :-)

  to get old systems running at a low cost, and I
think that means original
 or functional equivalent parts. 
Ah, but the modern/larger EPROM _is_ a functional equivalent part.

Yes, obviously you use the original type of EPROM if at all possible. But
if you _can't_ get the part, then it makes a lot of sense to use (say) a
2764 with the same code in it.

A secondary issue occurs when the original part was a mask-programmed
ROM. They can fail as well... Or you might want to make some changes to
the code. In that case you virtually have to use an EPROM and make an
adapter.

-tony