Help with PCB ID

Chuck Guzis cclist at
Sat Mar 13 14:04:08 CST 2021

On 3/13/21 11:43 AM, Cory Heisterkamp via cctalk wrote:
> I’m wondering if anyone recognizes this PCB.  Double-sided, 74xx vintage, measuring 14”x15”. There’s a “B.I.” logo in one corner, but no google match. IC date codes are ’77/’78 vintage.
> There’s a pair of DB-25’s, a BCD encoder, and for some reason, two pots. DC rectification appears to take place onboard. I thought perhaps the 112-7753 marking might be a part or catalog number, however the flip side is marked 112-1754, so perhaps not.
> Anyone recognize it?  -Cory

Looks like the board from a B100.   Note the connectors and switches on
rear panel that seem to correspond with this:


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