Another HP-67 repair query

[teenix]

(10-14-2020 09:33 PM)coitboy2000 Wrote:  Unplugging the card reader had not affect. Is there any way to check some of the ICs ? I have a 4 channel scope.

Richard

I've put some info here for classics but it may prove useful near end of document. It won't be too hard to check display drivers if you look at the circuit diagram.

http://www.teenix.org/ClassicNotes.pdf

HP-67 circuit

http://www.hpcc.org/cdroms/schematics5.0...c/hp67.pdf

cheers

Tony