PET 2001-32N with unknown circuit.

[Muttley Black]

Hello all.

Today I got this beauty and inside I found this circuit. Anyone know what is it?

Thank you!

 

[Eudimorphodon]

I will hazard a guess that it's a Centronics parallel printer interface. It's interesting that they hacked it straight onto the motherboard like that instead of making it a self-contained plug-in to the IEEE-488 port, though.

 

[Muttley Black]

Thank you for your answer. I am going to move it from the board for now.

 

[dave_m]

Yes, remove it if you do not have or want an old dot matrix printer. That is one of the worst examples of a 'Kludge' I have ever seen. It could have been done much neater using the IEEE connector as Eudi mentioned.

 

[Dwight Elvey]

It is clearly not a printer interface. 7485s are magnitude comparitors. There are 8 of them and each compares 4 bits. That would be 32 bits. There doesn't look to be enough wires to send 32 bits from the pet to the board. There is clearly not enough storage on the board to hold 32 bits of data. My guess is that it was used to monitor something that might be changing values over time. That is my best guess.
Dwight