4 Apr
2002
4 Apr
'02
1:06 a.m.
--- Pete Turnbull <pete(a)dunnington.u-net.com> wrote:
On Feb 26, 8:50, Sellam Ismail wrote:
I can. We used 6309s in our original COMBOARD-I. I don't know if I
can download a file into my ancient programmer, but I know it will
copy 256 byte bi-polar PROMs (I made many, many sets on it as a teenage
stock boy/part monkey). Worst case, we type the bytes in on the hex
keypad.
There's a 74-series drop-in replacement for the 6309, 74S471? I know in
the late 1980s, we were having problems getting PROMs to make boards.
Don't know where to get blanks from these days. Of course, one could
manufacture a 27xx->6309 pin swabber and use a 2716 or other readily
available EPROM. There might be a vertical clearance problem with that,
but electrically, it should work
just fine.
On Tue, 26 Feb 2002, Paul R. Santa-Maria wrote:
> I have received a box of old Apple II disks including a bunch of
> 13-sector disks... Does anyone here still have the 13-sector boot
> PROMs for the Disk II controller card?
> > These are small 256-byte PROMs; can anyone here burn them if I cannot
> > find originals? > I've been searching for years and I don't
think I've ever even seen a
> 13-sector disk controller. Just about everybody updated their old
> 13-sector boot controller when the 16-sector version came out.
That's my memory. I haven't used a 13-sector disk in a very long time.
As Sellam implies, it's only the boot PROM (P5)
you need to change, not
the state machine PROM (P6). I have a card somewhere with BOTH sets,
switch selectable, but I haven't seen it for a while.
If anyone can cough up an old PROM, that's the first step.
-ethan
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