Found an HP 67, what now?



I recently picked up an HP-67 at a garage sale. I had no idea what it might be worth but I was fairly certain it was worth what I paid for it. The calculator came with a soft case, quick ref card, AC power adaptor, & a stand alone battery charger. Unfortunately it did not come with any manuals or blank magnetic strips.

There is a strip with some key functions written on it that is directly above the keyboard. I'm guessing that this is a mag strip that has been inserted into the upper slot after it was at some point in the past passed through the lower slot.

See my absurdly high resolution photos at:

So with no blank cards and no instuctions I'm sort of at a loss as to how to tell if my unit is fully functional. Id like to do a test to see if my unit needs the "gummy" wheel repair but I need a card to do that and I can't figure out how to remove the card from the upper slot.

I have read that trying the card reader while on AC power is a bad idea so even if I had a card I'm not sure that I should proceed.

I'm guessing that my best course of action is,
A) Buy manual
B) Buy battery pack
C) Buy mag strips
D) Test

Any tips or suggestions would be welcome as would any offers to sell me a single blank magnetic strip. I see that I can get the manual off of this site and will probably do so and the batteries seem to come up now and then on e-bay. However, if anybody has an alternate source on the batteries they could point me to I'd appreciate it.

Any other tips/tricks/pointers would be welcome as well.

BTW, If my unit does need the gummy wheel repair, I may even try it myself given the excellent directions on this site.

thanks for any help or tips,



I can't get the URL you've given to work at the moment, so I can't see the pictures.

That said, I can give you some general comments.

There has been some debate here recently as to whether it is safe to plug an HP67 into the mains adapter without a good battery pack in place. The card reader sense amplifier chip _is_ directly connected to the battery terminals and will get a higher voltage than it should if the charger is connected without a battery. Whether this will damage the chip is another matter, but as the chip is HP custom, I don't like to risk it.

There is a guy on E-bay who sells reproduction batteries for these machines (it's the same battery as the 35, 45, 55, 65, 70, 80, 75C, 82168). Probably worth getting one.

I am pretty sure the user manual is on the CD-ROMs avaiable from this site.

It is quite normal to label the 'top row' of keys -- the A--E keys on the magnetic card, and then slide it into the slot above the keyboard after reading it. The card slides in from the right hand side of the machine and should be able to be slid out again towards the right. There are no catches or anything.

Unless your card reader roller has been replaced, it will need repair. In fact I think even if the machine was repaired by HP at the last date that HP repaired these machines, the roller will need replacement by now.


You lucky man!

There is quite a lot of information about the HP67 on this web site, enough to get started anyway, so I'd say a battery was your highest priority...

I hope it 'just works' - have fun!

Mike T.


Hi Blake,

I jus happen to have three magnetic cards for the 41.
I think they are exactly the same as the 67 uses. Anyone?

If you like I will mail one to you for free.

You can write to me at to let me know where to post it.

Don W


They are indeed the same, Don.

If he's going to use that 67 much, he'll need several cards at least. It doesn't have continuous memory, so anything you want to save, you have to write to a card. But one will certainly do for testing purposes. 8)


Actually I have three. Mot many, I know...



I was going to suggest that he buy an 80 pack of cards, after he's sure the card reader works. Having one to test would seem to be essential though.



Thank you very much for your offer of a free mag card for my HP 67. It never ceases to amaze me how generous people can be with their knowledge and support in forums like this one.

I have sent a message to your e-mail with my address.

Thanks also to all the others who posted replies to my "newbie" thread. I'm really excited about tackling this project and am looking forward to posting the results.

I'm going to order the manual on CD from this site and pick up a battery as soon as I can. Thanks for listing all of the other calculators that share the same battery packn as I'm sure that will help.

About the gummy wheel, apparently its almost a forgone conclusion that it will need replacement. Should I just go ahead and open the unit up to verify the wheel's condition? And if it's bad, I imagine I should go forward with the wheel repair before even testing the mag reader since I'm guessing that the mag reader won't work properly until the wheel is functioning correctly.

Basically I'm wondering if I could make the condition of the calculator worse by testing a mag card before replacing the gummy wheel. The old wheels look really awful in the pics posted on here and I'd hate to spread that gunk around inside if I don't have to.

Thanks again for your help,




I've just been reading a little further on here and it seems that even using the adaptor to power the HP 67 when there is no battey inside can cause damage?

Of course, I knew nothing of this and had already done this a few times so I guess I have to keep my fingers crossed that I didn't fry anything already.

So the revised project order as of now looks like,


2) Get manual and read it!

3) Charge batteries in the stand alone charger

4) test non mag card calc functions using battery power only.

5) Crack open unit and inspect gummy wheel

6) Replace wheel if needed (99% chance)

7) test mag card function using battery power.

8) Rejoice/swear at my good/bad fortune.

how does that look?


Hi Blake,

You have probably gotten away with powering it up w/o batteries, but obviously it's not wise to push your luck.

I never owned a card reader, but if that decomposed plastic gets on the actual read/write heads then the thing will be history. The recording / playback gap is only 1/10th of a thousandth of an inch (or less) wide so it's really fragile.

While the machine is apart you could clean the head with a kit like they had for manual cassete head cleaning (remember them?).
Also, be sure not to bend the microswitch actuators as this causes grief from what I have read here.

I will send you some cards on thursday (payday) by air mail.

Good luck.

Don W

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