TI-58C Display Problem

[teenix]

(11-20-2018 09:43 AM)DANTONVB Wrote:  It had broken battery contacts, due to battery leakeage, but it was operating as expected. Then I cleaned the battery residues in the calculator PCB, using vinegar and after rinsed with water, and soldered new battery contatcs.

Cant be sure, but it is possible that the battery leakage caused a "thinning" of the pcb tracks by corrosion. Cleaning that corrosion off might have thinned them even more and they might now have some resistance or a hair line crack which is affecting the display operation.

I would re-check the pcb to make sure everything looks ok, ie nice clean solder joints, not dull and pitted, pcb tracks intact and no moisture from the cleaning hiding under IC's etc.

Corrosion may have affected a components connection to the pcb and it can be loose. Gently wiggling components like resistors and capacitors might show up a problem.

The IC's on the board will be sensitive to static discharge from fingers etc, best to handle the pcb by its edges.

cheers

Tony