6 Sep
2007
6 Sep
'07
5:02 a.m.
Ethan Dicks wrote:
Ah... good to know. The PDP-8/L and -8/i have a 7483
on each M220
card, but I remember seeing either a 74283 or, if it exists, a 74183
in the design for that PDP-8/i work-alike I mentioned here a few weeks
ago. The difference, I would guess, is probably that the designer of
the clone didn't want to fiddle with an older, odd chip.
Unicorn electronics still have 74XX listed but many of the chips
are (Discontinued -- limited to stock on hand). Oddly the 7483 does
not state that. They also may have 7482's -- dual adder,
as I think they where used the original PDP-11.
I should probably find a source of a handful of 7483s
since I have a
small stack of dead M220s. I don't know what's wrong with them yet
(probably dead 7474s if the rest of the machine is any indication),
but I'd hate to trace it to the adder and have no spares on hand.
Where do most people get their spares from?
I did not realize it was a strange-power-pin part. I
would have
figured it out eventually, but it's best to be forwarned.
-ethan
Ben alias woodelf