21 Mar
2015
21 Mar
'15
12:58 p.m.
On 21/03/15 19:39, Jon Elson wrote:
I got away with it, but
the Model 30 was only 10 (or fewer) years out of
service. By defeating interlocks it's probably possible to get a 2311 to
spin up without a pack and have it load the heads (with something soft
between them!) to check head loading and cylinder actuation. I'm not
sure what diagnostic facilities exist for the 1800, but the 2841
controller had microcode routines to manually test drives.
On 03/21/2015 01:47 PM, Johannes Thelen wrote:
Yes,
hydraulic actuator. Assuming it hasn't run for a long time then
flushing and replacing the hydraulic fluid would be necessary.
Thanks Jon for tips!
No, that is not option, I mean 2311 is have to get back to life ;) I
think use ultrasonic or carbon ice cleaning for 2311 and disk packs.
Both are quire gentle cleaning methods.
You have to be very careful with anything
that requires temperature
extremes. Can anybody verify the 2311 uses the hydraulic head
positioner? If the oxide coating of the packs has deteriorated, which
I think is quite possible, then the disks will not be usable. Anybody
else have experience with 14" disk packs from 40" years ago?
The other problem is this machine uses SLT. That was never a
super-reliable technology. They start with 1/2" square ceramic
substrates, and fire thin film resistors onto them, then print and
fire thick film wiring. Then they use bump-bonded discrete
transistors and diodes, and solder these by bump bonds to the wiring,
and add leads. Then, because the transistors and diodes are not
well-passivated, they smear silicone goop over it and epoxy on the
die-drawn aluminum covers. These are not totally hermetic, and oxygen
gets inside and slowly deteriorates the semiconductor devices. They
also had some problems with the solder joints to them developing cracks.
The plus
side is that you can pretty well replace a module with a few
transistors/diodes/resistors, if you have the manual that shows you what
is inside each one. Also, the same SLT card will be used in many places
so it's easy to swap them around. For the Model 30 there was a manual
that showed where each card was used, which facilitated this swapping.
Of course there were odd cards that only appeared once or twice.
So, the likelihood of the CPU actually working after FORTY years of
storage is pretty small. There are, of course, no replacements for
SLT modules, as IBM stopped making them in the late 1960's! It was a
form of diode-transistor logic, and not terribly dense. A single
flip-flop would not fit in one SLT module, it took at least 2, and the
usual scheme was to integrate some steering gates with it and ended up
with about 4 modules to implement the typical register bit. They
didn't use what we think of today as a FF, they used D latches, as it
was simpler to implement, but required several clock phases. One
clock phase to latch input data to the ALU, wait for the ALU to
settle, then a pulse to latch the result out of the ALU.
The power supplies would
be the first thing to work on - they'll be
switchers and have the potential to make a very large bang.
I like to
dump core and all disc packs for future uses ( = make
original configuration).
I wouldn't worry about what is left in core, it would
be interesting,
but you might have to do a lot of testing and repair before enough of
the machine is working to read it out.
Be very careful with the disk drives. If you even get a scratch on
the heads, you will not be able to replace them. Also, if anything at
all happens to the heads, you will need an alignment pack to realign
any replaced heads. Do you have ANY experience with old-school
mainframe equipment? If you think you will just dust this thing off,
mount the disk packs and fire it up, you are quite crazy!
Jon
Lawrence
--
Lawrence Wilkinson lawrence at ljw.me.uk
The IBM 360/30 page http://www.ljw.me.uk/ibm360