6 Oct
2013
6 Oct
'13
3:40 p.m.
On 10/4/13 6:38 PM, Josh Dersch wrote:
On 10/3/2013 9:49 PM, Jos Dreesen wrote:
Looking through the pictures of your machine, it is interesting to note the differences
from
mine (serial #95) to yours (serial #277). Seems like they must have been on an
evolutionary
track in production as they are both labeled PDS-1D. My console is the older triangular
box,
like used with the PDS-1, but mine has LEDs and paddle switches (like yours) vs the
incandescent
lamp modules and toggle switches used on the PDS-1. Yours has the picture frame design
with
the additional selector knob. As I recall, this newer design console was used on the
PDS-4
as well. My keyboard is the same as used on the PDS-1 while yours has a newer style
enclosure
and set of keys. The top (100s) bank of cards on yours are mostly empty and unwired while
mine
contained the core memory and circuitry to drive it. Yours has a swing out door over the
wire
side of the backplane and presumably the large circuit card and possibly the memory are
mounted
on that door. Finally yours has control switches at the top front of the unit which are
either
not present on mine or are located on the back with the connectors. I assume yours
originally
had a desk top mounted to the top similar to mine, but that is only a guess.
--tom
On 10/04/2013 12:49 AM, Josh Dersch wrote:
Thanks. That looks like some very intense repair! Lucky that broken core was on
thecorner :). I'm
going to have to get a much more powerful magnifying glass to scope things out on the
Imlac's core
planes. Here's a pic of what I have to work with:
https://plus.google.com/u/0/photos/117997069161125071032/albums/58769649993…
and
https://plus.google.com/u/0/photos/117997069161125071032/albums/58769649993…
(where you can see an earlier repair...)
I'm hoping that the cores are OK, but given the way things are failing it seems
pretty likely. I do
have a second core set for this machine (the pictures above are actually of that set);
the logic
board is in much, much worse condition but maybe the core plane is OK. I may swap the
two at some
point and see ifthe other works any better.
Thanksagain,
Josh
Anyone with more experience here have any
suggestions?
Here you can see some pictures from my attempts at repairing some 8L core memories
:
ftp://jdreesen.dyndns.org/ftp/Cores/
I found dead / duff diodes , old solder joints of original repairs that had gone
high-ohmic, and
broken cores.
You want to make sure that all diodes have the same forward voltage when measured, and
all wires
have the same resistance. ( except for the sense line of course )
good luck should you find broken cores....
Jos