31 May
2012
31 May
'12
11:43 p.m.
On 5/31/12, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
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.
From the pictures on eBay, the disc drives look like
they are the P824
type mentioned in the P856 manuals on Theo Engels' site
(http://www.theoengel.nl/P800/P856-P857_System_Handbook_p4.pdf). This
manual mentions that the cartridges are IBM 5440 compatible. The drive
pictured in the book looks very similar to an IBM 5444 (with the big
clamps on each side). Any moving procedures for these drives that
anyone's interested in? Disk alignment issues I should be aware of?
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.
That's the usual routine. I'm figuring these have heavy linear power
supplies, right?
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.
I think Jos correctly identified the blinkenlights one as a P856 or
P857. The other two look like they might be P854's. Will post actual
model numbers and card id's once I've picked them up.
I also need to find a way to haul these upstairs... I don't think my
wife will be all that thrilled to have them sit in the living room for
a prolongued period.
Cheers,
Camiel