Need help with HP-71 HP-IL Interface Module

[wallyhp71b]

Hello - I would appreciate any help with verifying the working condition of my HP-71 HP-IL Interface Module 82401A.

I'm a long time HP handheld calculator user and just recently got out of storage (30 years) my old HP-71b calculator and accessories, including an original boxed Hp-71 HP-IL Interface Module 82401A. Everything in the box looks brand new. I must have bought this years ago but now don't have any HP-IL device to connect it to.

So how can I check to see if it's working?

The HP-71b works great. It powers on, with new batteries, and when I type VER$, displays "HP71B:1BBBB".

But when I[/size] plug in the 82401A module, the HP-71b does not seem to recognize it, and when I type VER$, still only displays "HP71B:1BBBB"

Also when I type RESET IO or RESTORE IO or try other HPIL commands, the HP-71 beeps and displays "ERR:excess chars".

It's been decades since I've used my HP-71b so I'm very rusty on using it now.

I've tried to do online research to re-educate myself on this but can't find any answers.

Any helpful suggestions that I could try, to verify if the Module is working, would be much appreciated.

Thanks for sharing your knowledge.

[KeithB]

While this does not seem to be your problem, it makes things much faster to attach an HPIL cable to the input and output of the device. That way it does not timeout waiting for a response.

[cruff]

Are you sure the IL module is fully seated in its slot?

[Sylvain Cote]

(01-14-2021 05:19 PM)wallyhp71b Wrote:  But when I[/size] plug in the 82401A module, the HP-71b does not seem to recognize it, and when I type VER$, still only displays "HP71B:1BBBB"

You have at the minimum a contact problem, because when plugged and working, VER$ should gives you "HP71B:1BBBB HPIL:1A" or "HP71B:1BBBB HPIL:1B"
Remove your HP-IL module and re-insert it to see if that helps.
Look at your connector inside your HP-71 to see if it is clean and also with a flashlight look into your HP-IL module to see if all the 13 pins are there and clean.

(01-14-2021 05:19 PM)wallyhp71b Wrote:  Also when I type RESET IO or RESTORE IO or try other HPIL commands, the HP-71 beeps and displays "ERR:excess chars".

Normal, the ROM has not been added to the system, see above.

(01-14-2021 06:51 PM)KeithB Wrote:  While this does not seem to be your problem, it makes things much faster to attach an HPIL cable to the input and output of the device. That way it does not timeout waiting for a response.

OFF IO will also remove the timeout delay.

edit: wrong word used for contact, corrected, thanks Dave.

[Dave Frederickson]

Sounds like a contact problem. Apply DeoxIT D100L to the contacts and insert/remove the module several times. If the module is difficult to remove it can be pushed out with a small wooden dowel through Ports 1 and 2.

[wallyhp71b]

Thanks for all the above good tips. I'll try cleaning the contacts and post a follow up on the results!

[wallyhp71b]

I tried cleaning the contacts and no luck. I cleaned the contacts on the inside of the HP-71 & the contacts of the module and re-seated the module several times but the VER$ command still returns only "HP71:1BBBB" and doesn't recognize the module.

The odd thing is that I have a second "new old stock" boxed HP-71 HP-IL Interface Module 82401A that I have also just tried and it also is not recognized by the HP-71b when it is plugged in.

Maybe the problem is on the HP-71 side with its internal port, rather than either HP-IL Module?

I have other Application & Ram Modules that are recognized when installed and pass the ROM TEST 1G 2G 3G 4G.

Any more troubleshooting ideas that I could try?

[Sylvain Cote]

(01-14-2021 11:51 PM)wallyhp71b Wrote:  I have other Application & Ram Modules that are recognized when installed and pass the ROM TEST 1G 2G 3G 4G.
Any more troubleshooting ideas that I could try?

The HP-IL port connector is the same as the front port connectors, so take one of your application module that you have verified that it is working, insert it into the HP-IL port and try VER$ to see if the module version is displayed.

[rprosperi]

(01-14-2021 11:51 PM)wallyhp71b Wrote:  I have other Application & Ram Modules that are recognized when installed and pass the ROM TEST 1G 2G 3G 4G.

The built-in ROM test only checks the built-in ROMs.

But it's easy to check the other modules; for ROMs, simply check the contents via

CAT :PORT(1) for port-1, etc.

If RAM modules, it's easiest to check them by changing to IRAM, then copy a file there and verify it.

FREE PORT(1)
COPY FILENAME TO :PORT(1)
CAT :PORT(1)
CLAIM PORT(1)

If these work for all ports (1-4) the bus is probably OK, and I would then recommend cleaning the contacts in the HP-IL socket (on the 'up' side of the board) with Q-Tips and some DeOxit as Dave suggested. Put a healthy (but not dripping) amount on the contacts and let it sit there for 10 minutes to dissolve any oxidation, then clean it again with clean Q-Tips. This should clean the contacts if that is the problem.

Has the case ever been opened? If so, perhaps the contacts were damaged?

Also, to totally reset the electronics, remove the batteries and the short the first and last pins in the card reader bay together. In dry winter air, its possible there is a static problem upon inserting the module.

[wallyhp71b]

Thanks for the tip. I'll get some DeOxit tomorrow and let you know the results.

[wallyhp71b]

Final update on this issue. Success!!!

It was the dirty contacts inside the HP-71b module port. After following the wise advice to clean the contact, I waited some time for it to dry, then reinserted the HPIL Module, turned on the HP-71b and did the VER$ command. I was thrilled and excited to see "HP71:1BBBB HPIL:1B" displayed.

Thanks to everyone for sharing their knowledge with me to get my vintage HP-71b back in service and to confirm the operation of the HP-IL Modules.

Take care....