I just acquired an HP-65 which was advertised as non working. It came in a beautiful case with the Standard and Math 1 pacs so I thought to give it a try.
Turns out the previous owner tried to power it up directly from the charger with no suggess, but when I installed a good power pack it instantly came to life.
The problem is some of the LED segments do not light up. As you can see in the pictures digits 3, 5 and 8 do not light up properly (the display should read -8888888888.-88).
Is there a known cure for this? Should I open it up and clean the contacts? Or is it a lost cause?
Thanks!!!
A Classic should run on the charger alone. If yours doesn't then there's probably a fault in the power supply within the calculator or even with the charger.
Re the LED, I think it's the LED display itself that's faulty. A fault in the anode driver would result in the same segment(s) missing from every digit and a fault in the cathode driver would mean entire digits not working. At least I think this is the case. Someone who knows more about the electronics will no doubt be able to put me right if I'm wrong (Tony? Bernhard?)
It looks like those LED segments have failed either fully or partially. I have seen segments fail like this before and it looks like the only way to fix it is to try to find replacements for the 5 digit LED modules (any classic types will do) or another key/display board.
cheers
Tony
(12-10-2019 09:29 PM)Moggul Wrote: [ -> ]I just acquired an HP-65 which was advertised as non working. It came in a beautiful case with the Standard and Math 1 pacs so I thought to give it a try.
Turns out the previous owner tried to power it up directly from the charger with no suggess, but when I installed a good power pack it instantly came to life.
The problem is some of the LED segments do not light up. As you can see in the pictures digits 3, 5 and 8 do not light up properly (the display should read -8888888888.-88).
Is there a known cure for this? Should I open it up and clean the contacts? Or is it a lost cause?
Thanks!!!
(12-11-2019 12:22 AM)teenix Wrote: [ -> ]--- the only way to fix it is to try to find replacements for the 5 digit LED modules (any classic types will do) ....
Search for QDSP6061 bubble display. Relatively easy to find.
Edit: But I'm not sure if this is the type with the decimal dot inside the number.
Bernhard
(12-11-2019 07:26 AM)PANAMATIK Wrote: [ -> ] (12-11-2019 12:22 AM)teenix Wrote: [ -> ]--- the only way to fix it is to try to find replacements for the 5 digit LED modules (any classic types will do) ....
Search for QDSP6061 bubble display. Relatively easy to find.
Edit: But I'm not sure if this is the type with the decimal dot inside the number.
Bernhard
Thanks Bernhard.
I found these on ebay:
https://www.ebay.es/itm/Vintage-bubble-H...%7Ciid%3A1
However I believe they are the wrong type: "Vintage 7 segment LED display, 5 DIGITS, decimal dot outside the digit." I am looking for "decimal dot inside the digit", right?
(12-10-2019 09:49 PM)grsbanks Wrote: [ -> ]A Classic should run on the charger alone. If yours doesn't then there's probably a fault in the power supply within the calculator or even with the charger.
I checked and the calculator runs when connected to the charger alone, so at least that part is good
(12-11-2019 04:46 PM)Moggul Wrote: [ -> ]However I believe they are the wrong type: "Vintage 7 segment LED display, 5 DIGITS, decimal dot outside the digit." I am looking for "decimal dot inside the digit", right?
Yes, in the middle of the CDEG segments.
cheers
Tony