HP-71B MultiMod ROM Emulator - Issues ?

[Sylvain Cote]

(03-27-2021 03:49 PM)Dave Frederickson Wrote:  

(03-27-2021 03:35 AM)Sylvain Cote Wrote:  All three modules work on S/N: 2713A00041 but none works on S/N: 2410A00146.
I know the card reader port works on S/N: 2410A00146 because it usually hosts a working FRAM71 module.

This could still be a contact problem. You might try giving the card reader port pins a good cleaning with DeoxIT "D" formula or a pencil eraser.

You were right Dave, I cleaned up the contacts and the three modules are now working.
But there is something fishy here between the card reader port contacts of that machine and the MultiMod module.
About half the time, if I plug any of the three modules it is not working, then I remove the module, re-insert it again, then it will work or not, redo the same thing and at some point it will work.
This is one of two main 71B machines were I plug and unplugged all kind of modules all the times and never had any issue with the card reader slot before, very strange.
Same machine, card reader port modules tested today and working on the first insertion time: FRAM71, FRAM71B, CMT-CR-96R #1, CMT-CR-96R #2 & HHP-71M/M-32K/32K.
Maybe the pins are little bit smaller on that machine and it is having difficulties creating a contact with the module pins, I do not know, more investigation is needed on my part.
Still, this is good news, all the modules are now working on that machine.
Sylvain