Possible Anode Driver replacement

[albertofenini]

Hi everyone,
while repairing some HP65s, I have noticed that one of the common failures in these calcs is often
the Anode Driver.

Searching on the Internet and keeping in mind that it should work with the LED module 5082–7415
https://www.datasheets360.com/part/detai...277639708/

I have found out this device Motorola MC144898
https://www.digchip.com/datasheets/parts...BP-pdf.php

Does anyone thinks is worth a try ?
It may have a different pinout but this is something that could be adapted

Please let me know your thoughts
take care, Alberto

[teenix]

(01-02-2019 11:36 AM)albertofenini Wrote:  Hi everyone,
while repairing some HP65s, I have noticed that one of the common failures in these calcs is often
the Anode Driver.

Searching on the Internet and keeping in mind that it should work with the LED module 5082–7415
https://www.datasheets360.com/part/detai...277639708/

I have found out this device Motorola MC144898
https://www.digchip.com/datasheets/parts...BP-pdf.php

Does anyone thinks is worth a try ?
It may have a different pinout but this is something that could be adapted

Please let me know your thoughts
take care, Alberto

Hi Alberto,

Glad to see you both are making progress.

I don't think these are suitable replacements. The data and clocking requirements would be different to that supplied by the HP65 cpu circuitry.

Plus the anode driver is also dependant on the inductors for each LED segment.

A complete redesign would be required, with an interface that responds to the cpu data and converts it to drive the new display type.

cheers

Tony

[albertofenini]

(01-03-2019 04:57 AM)teenix Wrote:  

(01-02-2019 11:36 AM)albertofenini Wrote:  Hi everyone,
while repairing some HP65s, I have noticed that one of the common failures in these calcs is often
the Anode Driver.

Searching on the Internet and keeping in mind that it should work with the LED module 5082–7415
https://www.datasheets360.com/part/detai...277639708/

I have found out this device Motorola MC144898
https://www.digchip.com/datasheets/parts...BP-pdf.php

Does anyone thinks is worth a try ?
It may have a different pinout but this is something that could be adapted

Please let me know your thoughts
take care, Alberto

Hi Alberto,

Glad to see you both are making progress.

I don't think these are suitable replacements. The data and clocking requirements would be different to that supplied by the HP65 cpu circuitry.

Plus the anode driver is also dependant on the inductors for each LED segment.

A complete redesign would be required, with an interface that responds to the cpu data and converts it to drive the new display type.

cheers

Tony

Thanks Tony, it was worth a try ....
This weekend will work on the card readers, will post the work done
take care Alberto

[Harald]

Hi Alberto,

as Tony has already mentioned, The anode driver in the classic series calculators is a completely different design. Have a look at this website. The reverse engineering was done by late Jacques Laporte and Eric Rechlin has gone to a lot of trouble to reconstruct his website. You will find a detailed description of how the display drivers work there.

Cheers,
Harald