TI-59 card reader note

[John Garza (3665)]

For those out there refurbishing TI-59 card readers... It's important that the battery pack be fully charged when you are testing your work. The pack can exhibit no other signs of being weak besides occasionally misreading a card. This can fool you into thinking you have made a mistake somewhere in your work. Load a pack charged overnight or mount the 59 on the PC-100A/B/C printer to eliminate that possibility.

Contrast this with an HP-67 that still read/writes fine even when the low battery LED is on.

-J

[vassilisprevelakis]

Hi John,

Talking about the TI-59 card reader, did your capstan degrade and if so, how did you fix it?

BTW I have these figures for the capstan rubber coating:
Ø external: 8,01 mm, Ø internal: 4,01 mm, width: 3,70 mm

Do they look close to the ones on your capstan?

Thanks

Vassilis
http://www.series80.org

[John Garza (3665)]

As for the rubber roller, I just buy them in bulk and use them as I go. But there is a fellow on eBay that sells individual kits with new rollers. Search for 'ti-59 repair' or the seller 'hp classic' from La Luz New Mexico. I have used his rollers in the past and can say that they work well. And he sends a little instruction manual for the procedure with some helpful tips and some felt to replace the felt that lies against the head and many times is deteriorated as well.

-J

[HP: 9100B/9815A/35/45/55/80/70/65/67/67T/97/97S/91/92/21/22/
27/25/25C/25E/29C/19C/10/31E/32E/33C/34C/37E/38C/41CX/71B/
28S/19BII/12C/15C/32SII/33S/35S/48SX/48GX/50G/Prime/DM32/DM42]
[TI: 2550/50/50A/51/51A/55/52/56/57/58/58C/59/60/66]

[Hiwi]

I know this ebay seller, but 50 Euros is too much, he sells a simple roller, some extras what i never needed.

I have experience with silicontube, i have 7x3mm, this tube "expands" to 8mm if mounted on the axle (which has 4mm dia.)

This works perfect since several hundred redings/writings.

My advice is when attaching the clamp over the gearbox: push down the gearbox until the stop on the housing.

Ralf

[John Garza (3665)]

Hi Ralf,

Nice to see a fellow 59'er out there!

One other thing I've experimented with is removing the top of the gearbox, and lubricating the gears. I use moly-di, the same stuff I use for HP worm gears.

You will be surprised how much quieter it is! I've always disliked the noisy TI card readers.

I also noticed another post by you about read errors. and tacking in a capacitor. I think the real issue there is the tantalum filter caps (4 of them) eventually go bad and need to be replaced on the PC board. These are connected to the Mag card chip - which can sometimes go bad as well. I think an issue contributing to failure is corrosion - even slight corrosion that comes from gasses leaking from battery packs. Nowadays I never keep a battery pack installed unless I'm using the machine. The caps are available - but expensive US $91 for a dozen. I remember when they were a dollar a piece!

-John

[Hiwi]

Hi John,
yes i have a nice working TI-59.

I like the Ti-59 very much but my focus is more on HP caclulators.

Some friends of mine collect all kinds of TI-59/58 stuff and I have to repair all these calcs and PC-100 printers, ouch.

Actually they are very cheap in comparison to HP calcs.

So meanwhile i have a huge 'collection' of spareparts.

Common problems are corrosion, problems with the cardreader, keyboard and memory and bad soldering. The PC100 has often problems with the powersupply, bad soldering shorted zeners...

The TI cardreader is a very robust construction, that could last forever. I had working calcs with capstans looking like new and others totally squished. I don't know why.

Cleaning the capstan with alcohol destroys the original rubber in any case! Bad experience.

Regarding the caps there are two kinds of tantalums on the board, the standard "teardrop-shaped" and the silver cylindric ones. These are very high quality and my experience is that they also last forever. The series resistance is always perfect. I never had a fail.
They are very expensive and hard to get. I bought a small stock from a german distributor in standard values.

Completely different than the cylindric type are the teardrop-shaped caps.
They often show a good cap value but a high serial resistance.
I replace them. But there are quality issues on the market. I prefer high quality Vishay or Kemet.
Sometimes i use smd versions.

I have done lubrication of the gears as a standard service with - guess what - moly-di!

I have a little tube of moly-di which is an oil additive for the gearbox of my Moto Guzzi motorcycle. I had nothing else on hand :-)

Ralf