How to check / repair a HP 82106A module for HP41C calculator ?

[Eduardo Mingo]

After several years I have tried to use my HP 41C, but surprise the calculator works perfectly and the memory module looks dead.

Someone could help and tell me I can do to repair it?.

Thanks.

[Raymond Del Tondo]

It's rather unlikely that the memory module is dead. Please insert it into one of the ports, XEQ SIZE 000 , and see how many registers are shown, by switching to PRGM mode. If there are more than the built-in 64 registers, the memory module is working. On an HP-41C after a "Memory Lost" the display should show "00 REG 127", which is 64 regs (built-in) + 64 regs from the memory module , minus one register for internal used purposes.

HTH

Ray

[Dieter]

Quote:

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On an HP-41C after a "Memory Lost" the display should show "00 REG 127"

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Are you sure? IIRC the additional RAM is used for more data registers by default. In other words: after a master clear ("MEMORY LOST") the 41C will still display 00 REGS 46. But with one standard memory module installed it will now have 81 data registers. So RCL 80 should work fine and without the error message that appears with a standard 41C.

By the way - I would not put too much effort into a simple standard memory module. For an 41C, I think the Quad RAM (82170A) is the way to go. It upgrades the machine to maximum memory, and it occupies just one single slot.

Dieter

Edited: 5 Jan 2013, 5:42 p.m.

[Raymond Del Tondo]

Quote:

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Are you sure?

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Yes, after a SIZE 000:-)

Quote:

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IIRC the additional RAM is used for more data registers by default. In other words: after a master clear ("MEMORY LOST") the 41C will still display 00 REGS 46.

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That's why I wrote XEQ SIZE 000 ;-)

Quote:

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But with one standard memory module installed it will now have 81 data registers. So RCL 80 should work

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I think it's easier to memorize the SIZE 000 method, than to recall the highest register number for one, two, three or four mem modules.

Quote:

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By the way - I would not put too much effort into a simple standard memory module. For an 41C, I think the Quad RAM (82170A) is the way to go.

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Indeed:-)

Ray

Edited: 5 Jan 2013, 5:53 p.m.

[Luiz C. Vieira (Brazil)]

¿Hola, Eduardo; que tal?

I would like to know how did you get to the conclusion that your module is dead. Would you tell us what did you do to test the module and what results did you get?

Best regards.

Luiz (Brazil)

[Diego Diaz]

Hi Eduardo,

I agree that quad mem is THE way to go with a 41C, however if you have your reasons to repair the 82106A I'll gladly mail an internal chip so you can replace the damaged one.

Please e-mail me in case you finally decide to give it a go.

Diego.

BTW, Some repair/soldering skills are required to face the replacement job.

[Eduardo Mingo]

Dear Ray:
Thanks for responding and sorry for taking so long to my response.
After performing a XEQ SIZE 000 the size remains 63, but gives the impression that the module does something, because to press the key program takes longer time to response, diferent without the module of memory. (Sorry for my bad english)

[Eduardo Mingo]

Thanks for the reply Dieter:
I think your idea is correct and I will try to buy a quad module.

[Eduardo Mingo]

Thanks for responding Luiz:
The test is basically indicating for Ray and the result for XEQ SIZE 000 put the program size at 63 (not at 127 as would be expected).

[Eduardo Mingo]

Diego, thank you very much for your answer:
I appreciate you send me the scheme, and trying to repair the module.
I lose nothing to try.
Thank you so much.

[Diego Diaz]

Hi Eduardo,

No such scheme, it's just a chip soldered to the connector, plain easy replacement.

I've got a number of such chips from my Clonix/NoV projects.

Keep in contact by mail.

All the best from Dominican Republic.

Diego.

[Dan Grelinger]

Has no one asked what port the memory module must be inserted in? Port 1, or the expected memory will not be there. Remember: "No gaps".

Memory modules go for a few dollars on ebay, so if postage is involved in getting the memory chip delivered, might as well save the work and just get a used memory module. Quad memories seem to go for around $25 at best.

[Eduardo Mingo]

Thank you very much for the reply Grelinger:
Indeed the module is in the correct port (the number 1), and I started looking for the quad on Ebay but not so many modules to buy as it looks.

[Dale Reed]

Raymond,

Thanks for the clear description. I recently acquired a 41C (tall keys, great shape!) and a quad memory module. I hadn't started into the manuals yet, but your procedure let me test the module.

I'm certain the procedure is in the manuals I have (somewhere). But the timing of this thread and your posting was incredible. Lucky me.

Module is good, by the way. IIRC, it showed something like REGS 311. Sweet.

Dale