Texas Instruments TI59 weird card problems

[voltaage]

Hello Klaus!

In fact, that was what I initially did when the calculator arrived home. I built a battery package using only aluminium tape to make the contacts. Although it worked for the first 30 minutes, It started to get an inconsistent connection due to the high pressure printed by the contacts onto my poorly-crafted aluminium contacts (eventually they got chewed-up). The next day I did a better job with a thicker sheet of can aluminium; I just had to make sure that the negative battery contacts had enough pressue to keep them connected. Also I had to remove the varnish of the sheets and sand them a little bit. Unfortunately what I described at the top of the thread was just after that mod. Even I got to power my calculator directly to a power supply with a pair of cables, but the problem was still there.

Thanks for your reply but seems that something bigger is going on.

(10-27-2021 08:49 AM)Klaus Overhage Wrote:  It was due to contact problems with these metal strips. I cleaned the tips of the metal strips and the contact areas on the battery pack with an alcohol cloth and bent the metal strips up very slightly.