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HP Forum Archive 15

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Corrosion and battery leakage
Message #1 Posted by Charlie O. on 18 May 2005, 11:10 a.m.

After searching unsuccessfully for a TI forum I decided to ask here. Yesterday I found a TI 58 c in nearly unused condition. The battery pack leaked and there is a white substance on the sides of the battery compartment. This pack is similar to the one used in the HP 67 except the TI has the pc board exposed. Some of the traces around the battery contacts and the contacts are covered with a blue crystal stuff that is stuck very tight to the board and contacts. Also, 2 contacts under the module are green but don't have the crystal look.

I would like to know how to clean this stuff without further damage. I lost a battery contact while poking with a toothpick.

Thanks for any help.

Charlie (Phoenix)

      
Re: Corrosion and battery leakage
Message #2 Posted by Ron Ross on 18 May 2005, 11:30 a.m.,
in response to message #1 by Charlie O.

Get an old tooth brush and start with some distilled water (hell, its a Ti, you can use tap water for all I care!)

Open the case to get a better view of the rest of the board, or not!

Scrubb it and then rinse. Then, you might try some jewelery cleaner and scrub again in the battery pack area. You may just want to use Q-tips and clean the battery contact area. This is to prepare for a battery solder attachment.

Can you solder?

Buy a cheap 4.5 V phone battery pack from Radio Shack (You do have the charger, don't you?). Solder in onto the two battery terminals (Check http://www.ti59.com/ for details or information). The Ti-58 is basically a Ti-59 without a card reader and half the memory.

All of this can be for naught as the 58 could have further corrosion inside that may have ruined the traces between chips or even bad chips due to over Voltage or abuse in the past. Looks can be decieving.

      
Re: Corrosion and battery leakage
Message #3 Posted by Frank Boehm on 18 May 2005, 12:07 p.m.,
in response to message #1 by Charlie O.

First: the "crystal stuff" is toxic and you should not touch it - besides that, it is not environment-friendly (aka toxic waste)

But as already suggested: the "white crystal stuff" is solvable by water; the hotter the water, the better it is solvable (hot water from the tap does the job). The "colored crystal stuff" is possibly not easily solvable, some physical force has to be used. The metal is very likely corroded and should be treated carfully, as it is weakened, springs and contacts might break when treated with too much force.

      
Re: Corrosion and battery leakage
Message #4 Posted by Charlie O. on 18 May 2005, 2:14 p.m.,
in response to message #1 by Charlie O.

While waiting for a reply here I googled and got a pinball/jukebox site that says to use 50/50 white vinegar/pure water for alkalines. Another site says alcohol/acetone for the nicads. The white stuff shouldn't be a problem but the blue crystal corrosion that is growing around the battery contacts, some traces and solder connections may be fatal. Thanks Ron and Frank, I'll use your suggestions, too.

There is not even a slight build up of greasy dirt around the keys so I think the calc had little use. A shame if the lack of use killed the calc. There was a RPN module available, maybe so HP users could use the TI.

            
Re: Corrosion and battery leakage
Message #5 Posted by David Smith on 18 May 2005, 3:31 p.m.,
in response to message #4 by Charlie O.

By all means use acetone on your TI calculators. It will turn them back into the sticky primodial goo from which they crawled. Acetone dissoves just about any plastic that you can name.

            
Re: Corrosion and battery leakage
Message #6 Posted by Ron Ross on 18 May 2005, 3:37 p.m.,
in response to message #4 by Charlie O.

I believe the RPN module is just to convert programs from either rpn to AOS or vice-versa. It does nothing for the actual operation of the calculator ie The 58/59 is still an AOS calculator.

If you have the charger and a VOM, you can plug in and verify polority of the contacts so as to attach the batteries in your battery compartment. The prongs that are there (and you said one is gone) are merely for contact onto the old battery pack.

You can gut the old pack and buy a smaller 4.5 volt phone battery and just solder in place. I have had excellent results with a Ti-58c with just such a repair. I also have a really nice Ti-59 looking unit, but the corrosion inside was so bad that I have given up on and may someday strip for parts if I ever need.

            
The TI "RPN Simulator" module
Message #7 Posted by Gene on 18 May 2005, 5:01 p.m.,
in response to message #4 by Charlie O.

Was a rom for the TI58/59 that allowed a user to key in HP97 (ONLY!) program keycodes into the TI58/59.

The module program would then translate the RPN code implied by the keycodes and create a TI58/59 user program that attempted to match the functionality of the original RPN program.

It did not affect run mode operation of the TI58/59 at all.

Not particularly useful, IMO.

And, it had quite a list of functionality that it did not emulate, such as rapid reverse branching (such as GTO i, where i was a negative number)

I have slightly more info about it here:

http://www.rskey.org/gene/calcgene/59mods.htm


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