HP-65 - 1604S01786 - Display faulty or Drivers faulty ?

[teenix]

(02-17-2020 12:01 AM)albertofenini Wrote:  Hi Tony
will try to get some spare LEDs that we have seen working for sure for the first block, and see if it improves,
for the second block, the one that has a faint partially lit digit, what and where should we check with the scope ?
What should we expect ?
Thanks !!!!!

The likely way the segments can light like that is if the cathode drive output for that digit is playing up. It should only have a LO signal on it when the digit is supposed to be on. If the scope shows flickering or noise on that output, it would suggest it is faulty.

cheers

Tony