30 Jul
2007
30 Jul
'07
9:54 p.m.
On 7/30/07, woodelf <bfranchuk at jetnet.ab.ca> wrote:
Ethan Dicks wrote:
I certainly didn't mean to "put you in your place" - just an honest
disagreement about switch costs. The most I ever paid for switches is
for my FP6120 - I needed to match specific paddles and a specific
soldering hole footprint and paid about $4/switch.
OTOH, I've bought fistfuls of similar (but not compatible,
unfortunately) C&K switches for $0.25 at Dayton, and for $0.50 at
Mansfield. The $0.50 switches are going into a PDP-11/70 front panel
- the bodies are compatible, but I still need a double-handful of
"real" PDP-11/70 rockers to go in them.
I've built Elf toggle panels for $5. A PDP-8
needn't cost more than
$15 unless you want very specific switches to match an existing
design.
Well I guess I got 'put in my place'. Now on to the next problem is TTL prom programing.
I ordered 74S472's and got MB7124H's. So is prom substitution
common?
My recollection of programming boot PROMs for our 1982-era MC68000
board was yes... we used to need 6309s (like on an Apple II disk
card), but routinely used whatever we could get with the same pinout
and geometry (256 x 8).
So who on the list can program proms since they are
needed on the larger machines and any microcoded projects
now drifting around this list?
I have an old Data I/O, but it's packed away and I haven't powered it
on in years. Mostly, I've been programming with a UP600A that might
or might not burn PROMs. I hadn't gotten as far as programming PROMs
in my F20 flights of fancy.
-ethan