THis is off-topic, I know, but I suspect there are some people here
interested in old telephones.
I have a Western Electric 500 telehpne on the bench. The standard US
rotary dial one.
As you may know, all the small components and the anti-sidetone
transformer ('induction coil') are in the metal box kown as the
'Network'. This is the normal type 425 unit
Anyway, I've remvoed this from the rest of the 'phone by disconencting
the wiring and drillign out the rivets (this was standard practice
accordign to one of the official repair manuals I read). I can refit it
using 6-2 UNC screws whcih are a perfect fit.
The 425 network was not field rpeairiable, and I can see why. After
bending up the tabs, I slid off the can to reveal the components in a
particularlly evil potting compound. It's not hard, it's sticky, I can be
scraped off (but I spent good quarter of an hour clenaing a screwdriver
after this). It will soften with heat (in fact a hot air paint stripper
gun wil lget it to drip off, but I was gettign the thing so hot that the
plastic terminal board was softening too). No solvent I have tried will
The BSP docuemtns simply call it an 'insulating medium' which is not much
Has anyone ever repaired such a Network block and knows how to shift this