DEC PDP-8/e H212 core mat repair

[Joshua Rice]

------ Original Message ------
From: "Tom Hunter via cctalk" <cctalk at classiccmp.org>
To: "General Discussion: On-Topic and Off-Topic Posts" 
<cctalk at classiccmp.org>
Sent: Monday, 19 Jul, 2021 At 06:33
Subject: DEC PDP-8/e H212 core mat repair
I am curious if anyone has attempted to repair (replace) a broken wire 
in a
PDP-8/e H212 (MM8EJ) core mat (8 k word). The cores are not visible 
without
a microscope. I cannot imagine how these were even manufactured and 
wonder
if DEC service centers repaired core mat faults or if faulty boards were
simply discarded.
CDC 6600 cores were huge in comparison and I would not hesitate to 
replace
a broken core wire on those.
Best regards
Tom Hunter


These patents might be enlightening. I'm sure there's others, but these 
are some i've found on a quick search.
https://patents.google.com/patent/US4161037A 
<https://patents.google.com/patent/US4161037A>
https://patents.google.com/patent/US3668664 
<https://patents.google.com/patent/US3668664>
Josh