HP97 The journey begins

[Harald]

(04-10-2019 02:39 AM)teenix Wrote:  Hi all,

Unfortunately the woo hoo turned into a boo hoo :-(

It figures just when you think you are getting somewhere.

I had to measure a track on the keyboard PCB to clarify something and as careful as I have been with the hardware, when I reassembled everything I didn't realise that the brass power switch had slipped out of its carrier and was resting on the circuit board. It shorted some tracks and looks like the cathode driver has now failed.

This is a plea to see if anyone has a spare 1820-1749 for the 67.

If not, I think I can recreate the functionality on a different chip. It is basicly just a shift register that has to sink a single LED current, and it also has the battery voltage monitor.

cheers

Tony

I am currently on a business trip. But when I get back home I will have a look!

Cheers,
Harald