9810 Magnetic card options


Would it be possible to use 9100 magnetic cards on a 9810?

Also, would it be reasonably easy to make a magnetic card that would work in a 9810 or would formatting it be too difficult?


9810 cards are much larger than 9100 cards... no joy there. You might try making some cards by gluing strips of video tape to a backing material (think plastic, card stock, etc) so that the tape is under the heads. I have used a spray adhesive and made workable 9100 cards this way. Spray the back of the tape, keep excess glue off the cards and tape edges.


Good idea! I'll give it a try and report back with my results.

I just finished up succesfully repairing the printer. The rubber on the paper roller had turned into a kind of gummy tar. I had to dissassembly the entire mechanism to free the paper roller. Then I had to think for quite some time on a way to re-create the rubber. I finally came up with a solution that involved making a nylon roller and covering it with some high-end 3M heat shrink. It works beautifully now.




How did you make the nylon roller? I have the same problem with a 9810 printer and haven't found suitable materials yet.



I had a machine shop make the roller from nylon round stock. I had them machine the OD to 20mm and drill a hole to allow press fit of a 1/4" shaft. Then we pressed the original stainless steel shaft into the new nylon roller (after removing the deteriorating original rubber).

Then I used a 3M heatshrink which has a layer of adhesive coating its ID (I think its called EPS-300). I carefully heated the heatshrink over the nylon roller. It came out very nice and even (the 3M heatshrink is very high quality). The heatshrink provides the roller with the grip it needs to move the paper and is just soft enough for the thermal head to make good contact with the paper.

I can give you more specific information if you email me.


If you can find some old 9 track computer tape, it may be more suitible than video tape. Probably reel-reel audio tape would work, but you would need to align the tape much more carefully when you glued it down. You need two strips on each card since the cards had an "A" and a "B" track.

The 9810 used two sizes of cards. Short ones did not hold as much data as the longer ones.


Do you have the exact dimensions for the 9810 card? Better yet, do you know where and how wide the magnetic strips should be on the card?

From http://www.oldcalculatormuseum.com/hp9820a.html it looks like the dimensions are:

6x2 inches and 10.5x2 inches for short and long cards respectively.

I figured that I could just glue two strips of VCR tape and was planning on looking at the card reader to determine where to position the strips.

If it turns out good, I might make a request for a scanner image of a 9810 card so I can have a more faithful reproduction ;) (I could print the image on card stock and then glue the magnetic strips on the back). The main thing is for it to work though.

I may have time to try it tonight.


I will try and measure some tonight. I would position the tape by looking at where the head is.


When you say 'exact' dimensions, how 'exact'? Do you want me to dig out the travelling microscope (yes, I do have one), or are the following dimensions, measured with a ruler, good enough?
The short card, part number 9162-0012 measured 6" long by 2" wide. The long card, part number 9162-0045 is 10.5" long by 2" wide.
There is, AFAIK, no pre-fomatting on these cards (or on the 9100 cards for that matter). The 9810 records 4 tracks in each direction (it's a 4-coil head). 3 data tracks and a clock track. Porgram keycodes on the 9810 are 6 bits long, and are recroded as 2 sets of 3 bits on the card. I am not sure how 16 bit data words are stored, probably as 6 3 bit words.
I must get round to reparing my 9810 card reader (it's got the 'stock fault' of the decayed roller, and is otherwise OK I think). I had also better figure out how the 9810 works before the HPCC conference in a couple of week's time (If there are any UK people here who would like to come to that (13th Sept in London), then e-mail me and I'll provide details).


I tried making a 9810 card from a file folder and VCR tape. The card has to make a sharp 180 after passing through the head and this was causing the tape to come unglued.

I eventually got frustrated and decided to try an 9100 card just for kicks and IT WORKED!. 9100 cards are the same width but only 3 5/8 inches long.

The 9810's card reader is full of light sensors (which use visible light) and so its smart enough to know that the card is shorter and so it waits for the next side. It looks like ~279 steps can be recorded on each side. I sucessfully recorded a 500 step program on one 9100 card (both sides). I also successfully recorded all of the memory registers on 2.5 cards (5 sides).



What kind of glue were you using?


I was using 3M spray adhesive...the basic kind. I noticed there was some 3m High Strenght for an extra $10....probably should have bought that.

It seems like there must be a source of magnetic card sheet like what the actual cards are made of. I'll have to look around.


I used the 3M Super 77 spray on a test. Seemed to work fine, but I only ran a few cycles. This is their medium strength spray. They also make a really nasty one (#99 ?).


Interesting about the 9100 cards. I'll have to try some when I get my 9810 card reader back together (I also have a _few_ real 9810 cards which I'll try first).
My 9810 reader is currently in bits, I am replacing the decayed roller (of course). I've made a puller tool and got the old rollers off the shaft. Now all I need to do is make a new roller with grooves for a couple of O-rings. I didn't like the idea of putting O-rings round the hub of the old roller -- I can see them slipping off after a little use.
The light sources for the sensors are filament lamps. I can't remember the voltage (it's either 5V or 12V, probably the former), but I do know they're a standard bulb (T1 size), available from RS components and/or Farnell in the UK. I guess they're available elsewhere too. Mind you, they're considerably under-run, so they should last a very long time.


I put the o-rings on my rollers without making grooves in the rollers first. I only used 2 o-rings...1 for each roller. It seems unstable to me too but I figured I'd try it for a while and see if they stay on. So far they're holding up fine (after ~50 card reads).

If they fall off, I was thinking of working them back onto the roller and placing several dots of super-glue gel between the roller and 0-ring (my rollers appear to be aluminum).

The 5/8"x7x8" o-rings are a perfect fit and grip the card nicely. Instead of machining groves into the roller, you might want to consider glueing some flanges on either side of each roller (like a train wheel only on both sides). I'm sure there are some standard washers out there that would work well.



Actaully, making a new roller from a piece of 7/8" brass rod took under an hour... It is a very simple piece of machining. Fitting it on was a little harder, it's all-to-easy to bend the shaft or crack the drive pulley. Anyway, it's done now.
And it works fine. Finally, my machine works with 9100 blank cards too, so I guess they all do.


I posted an article here http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=154 a couple of years ago when I came up with this repair using O-rings too. I used three of them to keep them stable and they've been working ever since.


Hi Katie,

I read your article before I my repair. It was very helpful (especially the o-ring size information).

I couldn't quite figure out how you used 3 though. My two rollers are far enough apart that a third o-ring would have just flopped around in that space. So I just put on o-ring on each roller. I was careful to get rid of any twists and the ring seems reasonably stable. If I have trouble with it falling off, I think I'll epoxy a washer on either side of the roller to act as a flange.





I guess that these readers differ from each other. Mine is spaced just right for 3 o-rings. Here's what it looks like:


Edited: 27 Aug 2003, 11:44 a.m.

Possibly Related Threads...
Thread Author Replies Views Last Post
  HP Prime Programming options Egan Ford 8 1,933 10-06-2013, 10:44 AM
Last Post: Eddie W. Shore
  New compile-time options for WP-34S Nigel J Dowrick 15 3,390 01-29-2013, 03:25 PM
Last Post: Stephan
  magnetic strip malfunction aurelio 7 1,895 01-14-2013, 12:25 AM
Last Post: aurelio
  Question about magnetic cards for the HP-41C Card Reader Namir 2 1,175 08-15-2012, 12:15 PM
Last Post: Namir
  HP41 Card Reader not Pulling Card Colin Verrilli 14 2,984 07-29-2012, 05:53 PM
Last Post: Randy
  HP-30b unknown options Christopher Johnson 3 1,105 02-01-2012, 08:37 PM
Last Post: Christopher Johnson
  Hp-41 time module options Raymond Wiker 20 3,344 12-13-2011, 04:32 PM
Last Post: Geir Isene
  12c won't turn on --- options? Gene Wright 8 1,759 10-28-2011, 10:45 PM
Last Post: gene wright
  Removing 9810 printer snap rings (circlips) David Ramsey 5 1,303 09-06-2011, 01:32 PM
Last Post: David Ramsey
  HP 41 magnetic cards giancarlo 9 1,918 07-29-2011, 11:37 AM
Last Post: M. Joury

Forum Jump: