21 Oct
2009
21 Oct
'09
12:13 a.m.
John Robertson wrote:
Josh Dersch wrote:
Thanks. The Astrocade's Z80-based. The I/O chip does not look like an
8255 based on the pinouts. (Plus, it's got inputs for analog joystick
stuff as well.) The schematic calls out several chips as "Custom" along
with the more standard parts (like the CPU and various bits of TTL glue)
so I'm guessing the I/O chip is not an off-the-shelf part. (Alas.) I
guess I'll just have to keep my eyes open for spares...
Thanks,
Josh
Ok, so it's stretching the definition of
"computer" but it _does_
have a BASIC programming cartridge and it IS classic (1978) so I
think it qualifies... Got me a Bally Astrocade that appears to have
a dead I/O chip. From the service manual, this is a custom chip
listed as PN "0066-117XX-XXYX"... I figure it's a long shot, but
anyone out there have spare parts for these? I figure if anyone
knows, they're on this list :).
If the CPU is a Z80, then the I/O is likely to be a 8255, if the CPU
is a 68XX then the I/O is likely a 6821, and if the CPU is a 6502,
then the I/O is likely either a 6520, 6821, or 6532. Check how the
power pins to it compare to those common I/O chips of the day.
John :-#)#