HP-32E missing segments

[Moggul]

My recently acquired HP-32E presents an strange behaviour. When switched on, sometimes the digits have missing segments, mainly the top one or the right top one, always missing on all digits. If I press the case together with my fingers near the battery compartment all segments appear again with none missing and they usually stay like that. This behaviour is quite erratic, sometimes happening and sometimes working ok.

I suspect the problem is caused by the connection between the battery terminals and the battery pack but the calculator is quite clean and in great shape.

Any ideas?

[Dave Britten]

If it's like my 38E, then it's probably the crummy solderless display board connection not making good contact. To fix it, I just soldered all the pins to the pads. You could also try cleaning the connections.

[Moggul]

(01-21-2020 09:01 PM)Dave Britten Wrote:  If it's like my 38E, then it's probably the crummy solderless display board connection not making good contact. To fix it, I just soldered all the pins to the pads. You could also try cleaning the connections.

Thank you Dave. I opened the calculator (easier than I thought, just a matter of some wriggling), cleaned the contacts with IPA and pressed the pinns more firmly into the pads. Now all segments light up as expected. Let's see how long it lasts...

[Dave Britten]

(01-23-2020 09:33 PM)Moggul Wrote:  

(01-21-2020 09:01 PM)Dave Britten Wrote:  If it's like my 38E, then it's probably the crummy solderless display board connection not making good contact. To fix it, I just soldered all the pins to the pads. You could also try cleaning the connections.

Thank you Dave. I opened the calculator (easier than I thought, just a matter of some wriggling), cleaned the contacts with IPA and pressed the pinns more firmly into the pads. Now all segments light up as expected. Let's see how long it lasts...

Great, with a little luck, that'll do it. If not, just apply a small amount of solder to the pads on the display PCB where the ends of the pins come through the board. There's no real reason to ever separate the pins from the display PCB, since the other end of the pins slides out from under the black spine, which creates a pressure connection.