John Robertson wrote:
An early 70s (?) local Canadian electronics catalogue (R.A.E. Industrial
Electronics) has some of these SCR/Bridge rectifiers listed on pg. 138 -
made by IR. See if you can find anything on the PACE/paks design. Happy
to email the two pages showing the IR versions...these devices with 6
terminals have up to six different internal configurations.

1-Single Phase hybrid bridge with common cathode connection
2-Single Phase hybrid bridge with common anode connection
3-Single Phase, all SCR, controlled bridge (8 terminals)
4-Single Phase hybrid bridge with doubler connection
5-Single Phase, all SCR, AC Switch. (anti-parallel controller) (4 or 6
terminals)
6-Single Phase, hybrid AC Switch. (anti-parallel connector) (5 terminals)


PACE/pak turned out to be the keyword needed. That found
http://www.vishay.com/docs/93754/vs-p100series.pdf
which is plausibly the modern device series. most likely
the single phase hybrid bridge common cathode version.

Now, if only somebody could give a similar hint about the board.....
With no numbers visible I know that's a long shot.

Fortunately, no parts are needed now, I just want to understand
what I'm dealing with before redoing the external wiring.

With thanks,

bob prohaska