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grsbanks · (This post was last modified: 12-17-2017 12:22 PM by grsbanks.)

(12-17-2017 08:29 AM)Csaba Tizedes Wrote: I have a TI-65 in a very good shape and working condition, but on the LCD some annunciators and the segments of exponent display don't lit. And few weeks ago the keypad second row from the bottom (RST/BST/SST/X<>Y/SUM+/1/2/3/-) stops functioning.

Have you got any idea it is easily reparable?

The TI-65 is a machine that I don't know at all. Actually, its architecture is completely different from the TI-66. For one thing, it's a TI device (as in made by TI) with a flexi-PCB and a couple of TI processors that work in a master-slave configuration. I'm guessing one of the CPUs manages the display and the keypad while the other does the actual calculations. The TI-66 is Toshiba-made.

Does the display blank when you press a key? If so, that's usually a reasonable indication that the same CPU is handling both.

It could be corrosion. That was pretty common for those machines that ran on a pair of LR44 button cells. If so then you might be in time to fix things given that the problems only started recently.

Looking at a picture of the machine's innards (see http://www.datamath.org/Sci/Galaxy/TI-65.htm), I don't see a screwhole so I suspect the case is held together purely with clips. In fact TI seem to have gone down the screwless route with this calculator as I see that the LCD is held on with heat-stakes, making dismantling that part extremely unadviseable.

Not an easy one here!