Thanks to the wonderful article by Mike Davis in the repairs section, I was able to repair the "gummy wheel" on the HP-67 I recently acquired.

There were certainly some thrills and spills along the way. On my first re-assembly of everything, none of the inputs were working. I thought I might have done something serious. But, then I just took it apart again and made sure I fitted the keyboard matrix tightly in place and re-torqued all the screws properly (tightly) around the keyboard perimeter. Fixed!

Another thing I'd add to the instructions -
Before placing the back cover, when testing the reader by holding the battery down over the contacts while running a card through: be aware that card read errors will prevent subsequent read attempts until the "error" message is cleared. If you have the calculator display turned away from you (which you will in this scenario), you'll have to check the display after each attempt and clear the error before attempting another read.

Also, make sure you have a very well charged battery (new) before you get going on this - as you may be reading 10-20 card passes while getting everything tested/adjusted.

I have been known to build the occasional airplane model, and due to this, I have these special swabs for applying glue in tight spots. These worked really well on the "goo" cleanup. My Q-tip cotton swabs were good for applying alchohol in larger areas, but tended to leave fibers on corners and such that I had to pick out of the works. The glue swabs were better in tight spots and didn't leave fibers - as they have a spongelike material that is resistent to model glue (and therefore alchohol!). Just a "tip" in case you have a hobby store nearby and can get these items.

Also, I suggest having a very good magnifing glass or other optical magnification aid - and plenty of light. I have a surefire xenon flashlight that puts out about 120 lumens. That may be a little overkill, but it certainly showed any imperfections and lit up the the tight spots nicely.

So, another HP-67 brought back to life!

-MikeO

Edited: 22 Aug 2008, 2:43 a.m.

Congradulations.

Mike T.