HP 17BII malfunction: cannot select RPN mode


My HP17BII has a malfunction when trying to select RPN mode.
When selecting "Modes" it hangs and show a strange display.

During My life I‘ve had an HP 25 for the High school, a 67 for my Chemistry University studies, a 41C used during my military service, a borrowed 38 for studying an MBA, and finally the 17BII.

I bought the 17BII on 1991 BECAUSE it had the RPN mode.
some years ago, a friend gave me his HP12C because he did not used it.
I left the 17BII at home and used it in few occasions.

Unfortunately I lost the 12C at the airport some time ago

I took the 17BII and the batteries were off. I replaced the batteries and when trying to select the RPN by pushing <Shift>, <MODES> it locked.

I remember that the 41C, could be set in "synthetic programming" mode. What my 17B shows in the display looks very similar.

After reading everything related to 17BII in the forum I learnt very much.
I knew that my calc was an “international” model, with 2 ROMs and an extended <MODES> menu

I also learnt how to perform the self test. The result was the following:
ROM, DRAM, URAM and KBD were OK. Final message was:


| OK-17B II – I |, (so version I for the main ROM)

Then, after pushing a key:



The forum also show me how to get the version of the ROMs, <CLR>& <4th Menu Key>, then <BACKSPACE>, giving the following display


| 021E8:71FC70E81FC73055 |

So there is information there about the 2nd ROM

After that, I tried to select RPN, but no result: same hang-up when pushing <Shift>, <MODES>
· Also no result when forcing the machine reset via <CLR> & <3rd Menu Key>
· Also no result when forcing a “MEMORY LOST” via <CLR> & <1st Menu Key> & <6th Menu Key>
· Also no result when short-circuit the batteries (without and with batteries, on ON and on OFF)

Now I think that the 2nd ROM – the “international” has some problem, despite the test doesn’t show any

I just want to have my old friend RPN mode

Any idea to restore it?

Thank you all


Sorry to say, but no idea at all.

Sometimes these old friends just die. Could be a stray gamma ray from far far away.

These pioneers generally are not repairable. Your best bet to find an original pioneer HP17bII is probably ebay. There are almost always a couple for sale at any given time.

Sorry it died on you like that!


Hi Rafael, Gene, guys;

chances are that you may have a bad contact (broken solder) in one of the many soldering points in the calculator. It would not be that hard to open it and resolder all of the IC's terminals IF you are an experienced electronics tech.

About the ROM's: most (if not all) of the necessary software of the USA-only 17BII is already built in the main processor chip, as it happens withthe HP42S, that shares the same structure and LCD. What we have outside, in the mainboard, are the placeholders for two IC's: the RAM and the 2nd. ROM (only for the intl. version).

What I am not completely sure is if the MODES menu might have some particular connection with the 2nd. ROM OTHER THAN the language selection. The RPN/ALG selection should not depend on whether the calculator has a 2nd. ROM or if it is USA-addressed.

I'd think of checking for cold soldering... And this leads to open the calculator, though.

Not so much of a help, indeed. I wish you success. And please, keep us informed.

Luiz (Brazil)


Luiz, Paul, you gave me the key!.
I thought that if IT WAS a cold soldering, I just needed the contact for a while. Just to re-establish my dear RPN mode.

I put the calc on my knee.
I forced a slight bending wth my hands and tryed the sequence:
<shift> + <modes> and IT WAS THERE! the menu was showing [...RPN...].
I selected it... The sensation cannot be described properly without getting Dave Hicks censoring it.

Thanks to all, Gene, Luiz Paul


If it comes time to open the thing up, you may want to take a look at the Forum Articles # 5 and # 199. Each has some information about how one might take the thing apart safely.

But, if the keyboard checks out during the self-test, the only hope I see is to look for broken traces and solder joints, or perhaps a stray piece of conductive material shorting something out.

I believe Randy Sloyer is still available at www.fixthatcalc.com -- he may be able to help.

Good Luck!

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