HP-67 Gummy Roller Successfully Repaired


This morning I was able to repair the gummy roller on my HP-67, S/N 2011S02569, using the instructions by Mike Davis on this site. The card reader works great now. The successful repair was remarkable on four counts: (1) I was able to get the calc apart without destroying it, (2) the fuel tubing I had happened to be the exact right diameter for replacing the roller, (3) the calc still worked when I put it back together and (4) the roller repair worked!

The only thing I would add to his excellent instructions is that when you put the card reader back onto the keyboard assembly, you should reassemble the two pieces like closing a book, instead of placing the reader on the keyboard, otherwise the leaf springs will fall out of their little grooves. One interesting thing was that before I took the calculator apart, I noticed some crumbly material that I thought was just random crud, inside the battery compartment. Upon opening the calc, the crumbly material turned out to be pieces of the old roller that had gotten through the little holes at the top of the compartment. The old roller had turned into goo and was all over the inside of the upper housing. But other than that, the calc is in quite good shape. The silver trim is almost completely intact, and the LED lens is clear.

I have a 55, a 67, a 97, a 34C and a 41CX that my former employer surplused to me. The 34C, 55 and 67 work fine, although the batteries on the latter two are "rigged" with alligator clips for the time being. The 97's battery pack is dead, but I do have the adapter, so it'll power up. Not enough current to run the printer and card reader. There are some non-functional keys on the 97, so it's more of a hangar queen at this point. The 41CX is out of commission due to some disintegrated internal posts and eroded battery contacts. I find it ironic that the youngest calc in my collection (the 41CX at a youthful 22 years) is the only one that is totally non-functional. My 55, which will be 32 years old in a few weeks, still works like a charm. Could HP's quality standards have started eroding as long ago as the early 1980s?

I acquired the "Standard Pac" of programs with my 67, including the famous "Moon Rocket Lander". My son nearly soiled his pants when I told him we would be able to play a moon rocket game on my nearly 27-year-old calculator, but I think he was disappointed that it was just a sequence of little red numbers instead of the color graphics he's accustomed to on his Game Boy.

I celebrated by ordering the site DVD. I can hardly wait to whip out the old '67 tomorrow morning at the office and say, "Excuse me one moment" while I feed a magnetic card into the whirring reader!


I can hardly wait to whip out the old '67 tomorrow morning at the office and say, "Excuse me one moment" while I feed a magnetic card into the whirring reader!

I just acquired a lightly used 97, and about the only thing wrong with it is the card reader. I am not as brave as you, as I can't even get a couple of screws out of the case. So this is a job for FixThatCalc or plasmoid, likely thie former. Randy resurrected my beloved 41CV for what I thought was a steal, and I have done everything to sing his praises beside propose marriage.

I would love to whip the old 97 out of the briefcase at a meeting and pass a card thru.... What a show stopper! You can keep yer Crackberry I say ;)

Enjoy your like-new 67.



Mike Davis fixed my 67 to perfection. Just love to hear the whirr and then LEDs showing the decimal place just as they were last programed.



I would love to whip the old 97 out of the briefcase at a meeting and pass a card thru.... What a show stopper!

But, Lester -- what a large briefcase you have!

All the better to dazzle you, my peers!


(With apologizes to the author of Little Red Riding Hood)

-- KS


Yes Grant,

I know what you mean. Although I went through school with a 29C, (which I still have) the 67 was the apple of my eye back then...but at $450 retail, there was no way I could afford one in those days. I've acquired one now (of course), working card reader and all.

Being able to not only record electronically onto the magnetic card, but also to be able to label the soft keys with it sure is nice, and makes it very usable...even in the face of more advanced machines. Enjoy!!

Best regards, Hal


Any tips on removing the back label would be appreciated... I tried the hair dryer trick on a 65, but couldn't remove the entire label, just peel back the corners. The repair isn't bad, but it is obvious by the crinkly label over the two screws.

Part of the problem was my fault, when the hair dryer wasn't working to my satisfaction, I decided to try (carefully) using a heat shrink gun. I guess I wasn't careful enough, as I warped the side of the calculator! Blast. It was in almost mint shape too. I guess I should have practiced on a different one...

PS: The repair itself was successful, I used the O-rings. However, I managed to break 4 of the wires from the read/write head to the circuit board, and they are a PAIN to strip and resolder. Be warned... The wires are somewhat brittle!



I just peeled the corners back. I am not quite fanatical enough to worry whether another collector might be able to tell. The label is tough foil and the adhesive is remarkably sticky for being 27 years old, so it goes right back on with just a bit of a wrinkle. I am guessing that HP designed the label that way on purpose so you could get at the screws without ruining the label. On the other hand, they could have just printed up a stack of extra labels and put those on after a factory repair.

Another tidbit from my repair job. The main chip had a white decal on it with some notes written in pencil to the effect that the calculator was serviced on June 21, 1982. It says, "H.G. - NTF - Rpl. logic - stack ch - check." I don't know exactly what it means (I guess the logic board was replaced), but it was entertaining to see it waiting there for me. I can't imagine someone doing electronics work on a modern calculator, much less leaving a note for the next guy to read!

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