Another HP-67 repair query

[coitboy2000]

(10-15-2020 01:26 AM)coitboy2000 Wrote:  

(10-15-2020 12:48 AM)teenix Wrote:  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

Wow, thanks Tony. It would be nice to save this calculator

Richard

I am out of depth on this I think. I have captured some scope images for the cathode, anode & led pins when the calulator is powered up, If I twist the the keyboard near the connector with the cpu board I get some random elements light up on some of the leds'.

https://www.dropbox.com/sh/3kvxiilqx1jd3...0_nLa?dl=0