31 May
2012
31 May
'12
7:32 p.m.
Hi everyone,
I won an eBay auction for three Philips P800 family minis with three
cartridge disc drives, disc cartridges, lots of spare parts, and manuals
Wow!. Let me know what models they are. All P800 stuff is pretty rare
(compared to, say, PDP11s), so you have some nice toys...
including schematics. All for the incredible sum of 10
euros 75. I saw the
auction when it had 11 minutes left to go while I was on vacation (I'm a bit
of an eBay junkie, although deals like this are becoming rare). I'm
collecting the systems this Sunday afternoon.
As the manuals are all in binders, I'm planning on feeding them all through
a scanner and posting them to bitsavers.
I look forward to being able to read them.
Now, I seem to recall that Tony Duell has some experience with these
systems. Is there anything I should be aware of before loading them on a
trailer? Do the disc drive heads need to be locked in some way? When I've
picked up the stuff, I'll post model and part numbers. Any advice offered on
how to get them going again would be very welcome.
I have some experience of these machines, I own a P850, a P851 and a
P854,.the last 2 with floppy drives. Alas I don't have the cartridge hard
disk (for some reason there is the controlelr for it in the P854).
Tje machines and floppy drives need not special precaution for moving
them. Be warned they are heavy, and it helps to have a second person....
As for the cartridge drive, I'd take the cover off before driving home
with it) and inspect the positioner). Try _very_ carefully_ to pull the
carriage towards the speindle. If it will move (and don't pull it far
enough to load the heads!), it needs to be restrained. If there's a
locking bracket it'll be quite obvious, you may have to remove it, turn
it round and screw it back in place, for example.
As for powering them up, again, nothing special. The noraml visual
inspection, then test the PSUs on dummy load is all you need to do.
These machines vary a bit in the CPU design. The P850 is hard-wired
logic. The P855, 852, 856, etc are microcoded TTL (I think). The P851 is
custom Philips bitslice ICs. The P854 is AMD2900 bitslice. The P853 (I
think) is a custom single-chip LSI implementation of the processor.
-tony