30 May
2006
30 May
'06
12:46 p.m.
That raises an interesting point, actually. If the
normal repair
method
when the machine was in active use was to replace a module (e.g.
board-swap), is it better (historically) to keep the machine as
original
as possible (by replacing just one component on the board), or to keep
the original repair methods? I know what I'm going to do, though.
An interesting question.
If you have a module of the same age, I don't see any problem with a
module swap.
That's what I do, but my modules are probably logically rather
smaller. One printed
circuit board holds one 3 input not-J not-K flip-flop. Another type
has four And gates.
When I eventually run low on spare modules I will have to start
component level
repair, hopefully being able to make 3 good modules out of 4 bad ones.
You are probably wondering what computer I have, it is made of
discrete Germanium
transistors and diodes, has 2000 words of 48 bit core store, drums of
12000 words,
half inch ten track magnetic tape at 300 bit per inch, card reader,
card punch, line
printer, paper tape reader, and a slow, more modern (BRPE) paper tape
punch.
It is an I.C.T. 1301 mainframe, first installed at the University of
London in 1962 to
handle administration, undergraduate matriculation and statistical
analysis of
exam results and allocating candidates their grades and printing pass
slips.
It weighs many tons and consumes 13kVA of three phase electricity when
everything is running at the same time.
In service it was normal to swap a complete PCB and send it back to
base for repair.
These would be repaired to original specification, going as far as
going though
quality assurance where they would test each soldered joint and apply
a dob of
red lacquer to each joint to show it had passed inspection.