Hp35 display problem. Opened without bending the sticker

[teenix]

(05-01-2020 01:30 PM)isanchez Wrote:  Following with the repair process, now I would request of your help: Where do you think it lies the problem: is it the display driver, a contact or more surely the full bank of leds? As I see that exactly all upper segments of the whole middle bank are missing, I got doubts of what is more probable, to start with ;-D.
Can I use the HP45 leds?

Well this is it, Thanks and kind regards!!

Ignacio

If all the top LED segments were not working I would suspect the anode driver or the circuit board, however in this case it is probably the LED package or the circuit board.

The upper segment is called the "A" segment. It is powered through the top left pin (looking down at the bubble lens side).

I would first check the connection to this pin on the circuit board. Look for corrosion or broken circuit track. Try soldering the pin again. (Not too much heat or you could destroy something inside)

If that fails then...

The same LED anodes are all connected together inside the LED package. If you look closely at it through the top you will see all the small wires doing the job. I suspect the connection from the outside pin to these LEDs has failed inside the package.

Yes, HP-45 LED packages will work in the 35.

cheers

Tony