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John Garza (3665) · 07-03-2022, 09:30 AM

Has anyone else noticed that TI cards degrade in their original wallets? TI-59 mag cards are the least affected, TI-58/59 plastic label cards become gummy on the printed surface until it sloughs away. SR-52 cards get blurry lettering and a pink background (instead of white). I have had some luck with adhesive remover and a mild warm soap bath. I have all my cards in paper coin envelopes now, but it's not a very usable situation. Anyone know of a replacement card wallet that will not deteriorate? It's a shame to spend all that effort to clean the gummy wheel issues, only to have more goo come into the reader from the cards themselves! -J

John Garza (3665) · 07-05-2022, 08:49 AM

I'm considering this:
https://www.amazon.com/gp/product/B07VWV...6ISX4&th=1

And putting 2 plastic rods down it to form 3 vertical channels for mag cards. This is similar to the old HP-65 mag card box. And the plastic looks similar, which never degraded the mag cards it contained.

albertofenini · (This post was last modified: 07-05-2022 02:01 PM by albertofenini.)

Hi there

i do have the very same problems with my SR-52 cards,
most are almost impossible to extract from the wallet for how much glued they have become

How do you guys clean them without compromising the magnetic surface and the printed side ?

I have tried with diluted grease remover but only to discover that the printed side has lost all the lettering ...

thanks for help
Alberto

John Garza (3665) · 07-06-2022, 05:58 AM

Alberto,

For removing the cards from the wallet - try pinching with your fingernail and gently rocking the card left and right while applying a steady pulling force.

There seems to be 2 sources of the goo - one is the chemical reaction between the card wallet and the cards themselves, the second is the little black 'write enable' stickers on user-written cards. Best to just remove all of those stickers - and instead disable the opto circuit that reads them - so that ALL cards are now writeable. Just be careful.

For the goo, I've tried Duck adhesive remover for the front, alcohol wipes for the back, all followed by a warm soapy water bath, then rinse. It removes the goo and does not affect the lettering. However, you have to keep the adhesive remover away from the back of the card (magnetic side), as it is oil based. Any kind of oil will seep under the surface and affect the magnetic particles (grains). The magnetic properties will change and the card may become unreadable. In the worst case, the magnetic material will lose adhesion and begin to drop off in tiny specks. Clean the front with a q-tip while the card is on a clean dry folded paper towel to catch any oil. A little oil seepage along the edge is OK. It's only a problem when it gets near the center line of the card - where the mag heads read/write the data.

SR-52 cards are hard to come by. I've even resorted to buying complete SR-52 packages on ebay just to get the cards that look clean in the pictures - not needing the calculator itself. But you only need to do this once or twice to get enough cards for casual use and demo purposes.

Best of luck with your 52 !

-John

albertofenini · (This post was last modified: 07-06-2022 11:07 AM by albertofenini.)

John Garza (3665) · 07-07-2022, 03:11 AM

You do some great work Alberto! Thanks for the links. I'm only now starting to work with the SR-52. Although I have done restoration work on HP classic machines.

I did find something unusual the other day; I wonder if you have seen it. On the TI-58/59 machines, each ROM library module has a card wallet with plastic (not magnetic) label cards for the programs in the module. These are usually gold lettering on a black background. I saw some cards that were the opposite. They had black lettering on a gold background, similar to the blank label cards that come with each module. This happened in a Statistics Module and most of the cards were normal, until halfway through the batch, the colors were reversed. This leads me to believe it was a printing mistake. Like a coin with two heads.

albertofenini · 07-07-2022, 09:11 AM

John Garza (3665) · 07-08-2022, 08:15 AM

Again, that's some amazing work. You repaired some machines with incredible amounts of corrosion! I guess I've been lucky to never some across units like that.

I like that you use coax insulator tubing on the HP card reader worm gear coupling. I've been using RTV sealant for that inside the metal sleeve. Your method seems a quicker and more elegant solution. Kudos!

And I like that you're getting your son involved. So many kids today don't appreciate the work that goes into keeping our technology running. I taught my daughter to solder at an early age and she learned to program on my HP-65 hunting wumpus!

All the best,

-John