1 Nov
2010
1 Nov
'10
3:25 p.m.
On 2010 Oct 31, at 3:00 AM, Jos Dreesen wrote:
So I have these 2 PDP-8/L core stacks I am trying to
recover:
One would be perfect, if bit 3 @ adr 0 would be alive...
Although this is 99.99% OK, it is of course not good enough.
The other stack seems to be a total loss :
2 sense wires are open circuit, more than 20 select diodes shorted.
Of course the further quality of the cores is unknown.
Is there any realistic way of getting one fully functional stack out
of these ?
Removing a single core from the really bad stack to the almost OK
stack would seems almost feasible to me, since address 0 is bound to
be on a edge of a core mat.
Any ideas / suggestions ?
Here's a photo of some core with spliced wires:
http://www3.telus.net/~bhilpert/tmp/coreMontage.jpg
I suspect these were fixes done at the time of manufacture, there are a
quite a few of them over a large ~64KB planar array. I don't think they
were (all) done to replace cores though, they don't seem to open all
the wires to be able to replace a core. Perhaps fixing wires that broke
during manufacture.
Don't know how the electrical contact was made in the splices, whether
soldering or perhaps some sort of pressure weld.
I don't know what size cores you're dealing with, these ones are pretty
tiny, about 1/100 inch OD in 128*256 arrays.
Also included is an inset showing what happens when one drops a
screwdriver onto the cores (guilty). The plane is just a display item
though, so it wasn't a crisis.
This is a 3-wire system, there is no diagonally-strung sense-wire.
