sábado, 6 de dezembro de 2014

Texas TI-58: Repairing the keyboard bounce and miss to register keystrokes


Dissemble the keyboard.





Prepare the keyboard 9 rows  joint points by tinning them.




Prepare the 9 Dome row sets by tinning the joint points on both sides.







Put back the 9 dome row sets by soldering them to the keyboard 9 rows joint points.











Re-apply the plastic cover to the 9 sticky dome row sets.





Testing. No bouncing and no missing keys.











domingo, 23 de novembro de 2014

35 years between these two calculators: HP-35 vs HP-35S



HP-35S year 2007 vs 2012


Both have Firmware Rev. 1 (display = 0)


2007:

2012:


terça-feira, 11 de novembro de 2014

TEXAS TI-59

For many, the best calculator in the 70's. Powerful and low cost made it so popular.


Card Reader.




















Power adapter / Charger
Model AC 9900/H  6.2VAC / 200mA / 3VA







Replacement Battery - wrong type, soldered to the calculator, and dead


 


After cleaning







Documentation
































Read Heads signal:




Keyboard replacment:






Initial testing:
Three jumpers are needed in order to a successful power On.
On the 8-pin female connector, from left to right in the picture:
- Connect together the 2nd, 3rd and 4th pins (power on switch);
- Connect the 5th and the 8th pins (card reader sensor);
- Connect the 6th and the 7th pins (card reader sensor).




Repairing the battery connector::




Assembling:






Final testing: