HP-67 card reader - To David Smith



#6

YOU ARE A GREAT GUY!!! I did what you said and adjust the little screws on my card readers golden plate. I also change 2 capacitors; it was hard and i did a lot of dissambly - reassembly but now IT WORKS LIKE A NEW ONE WITH 100% of positive writing and reading!!!

I even have some tears when i saw my first "programs" writing corectly try after try after hours of frustrating job!!!

I was obsess by the card reader for some days. Even at works during breaks trying some new adjustments. My co-wrokers said that i'm a fool to work on that "dirty antiquity" or "obsolete hardware" HP-67. Me too i don't understand, i'm probably sick, if you analyse that, it's hard to understand, specially for a guy how have a TI-92 plus on his desk but always use a CX or a TI-59. How can they treat this beauty as a dirty-hugly hardware?!?

Anyway, i just want to Thank you for your Tips, they were helpful.

I have another question : I install 2 oring to replace the gummy wheel but one of them is always "spinning out" of the sharf and touch the reader casing : how can i "glue" them in place?

Another one : What is the purpose or the screw-notch at the end of the white plastic shaft that hold the reader wheel in place - Allignement of the wheel?

Thanks again!

Michel
Quebec


#7

They can tend to slip. Not much contact.

The slot in the end of the shaft is for adjustments. The shaft is an eccentric shaft, which means as you turn the shaft, the shaft moves closer or farther from the roller. This can be used to get the correct amount of tension on the roller.

I set mine a little less than maximum tightness. Seems to work for me ok. I also set it this way because newer magnetic cards are thicker than pre-recorded cards. I have seen that if this is set to work only with new cards that pre-recorded cards might not read correctly.

#8

We understand your illness.

Most of us have it.

Pages and pages have been written trying to explain it here. The bottom line:

Restoring one of these beauties to new condition is a profound experience. Using them is also.

Think about the guy who just got his Model A running as good as new.

Good Health, Live Long and Prosper,
and (H)appy (P)rogramming!

Michael

#9

I always use the silicone fuel line for my reader repairs. It works very well and makes good contact with the cards. I don't like o-rings becuase they tend to slide apart and drag on the sides of the reader housing. Also I have never been able to find the proper (#005) size. The standard #006 size seems to be a tiny bit too big.

The shaft for the card reader drive wheel is actually an off-center cam. By turning it you can adjust how tight the roller grips the card. I try to set mine as loose as possible on most machines. You might find a machine that needs some more tension, but I never have (done over a hundred of them).

The final problem you may encounter is the coupling between the motor shaft and the worm gear. On quite a few machines it is worn to the point where it slips so much the card will not go through. In really bad cases it has crumbled to dust. Some people call this coupling a clutch and thing the slip is a good thing in case a card jams. I don't think so... the HP97 service manual talks about holding a card with tweezers and measuring the stall current of the motor. On machines with a slipping coupling I use a drop of rubberized super glue called IC2000 tire cement. It is used by radio control car racers to glue rubber tires onto rims. It would also work to hold o-rings. A little goes a long way... too big of a drop and you cannot slide the worm gear onto the shaft beacuse of fluid pressure. Dont let it get into the motor bearings.

A final final thing is a reader that screams like a banshee. This is caused by the tip of the worm gear scraping on the tiny thrust bearing ball embedded in the reader housing. I have found that a drop of lube here fixes the problem. I use a gun oil called Break Free CLP. I also lube the worm gear itself. Dont get the oil into the shaft coupling mentioned above. Just the tiniest film will do. A strange thing about Break Free is it seems to take a half hour or so to reach maximum effect.

#10

I always use the silicone fuel line for my reader repairs. It works very well and makes good contact with the cards. I don't like o-rings becuase they tend to slide apart and drag on the sides of the reader housing. Also I have never been able to find the proper (#005) size. The standard #006 size seems to be a tiny bit too big.

The shaft for the card reader drive wheel is actually an off-center cam. By turning it you can adjust how tight the roller grips the card. I try to set mine as loose as possible on most machines. You might find a machine that needs some more tension, but I never have (done over a hundred of them).

The final problem you may encounter is the coupling between the motor shaft and the worm gear. On quite a few machines it is worn to the point where it slips so much the card will


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