TI-H: Re: EL Backlight Auto-Off

Ok, I found a place on the TI-85 and the TI-86 that can be used

to turn equipment of when the calculator goes off.

On the display board, on the lower right side are solder pads

for a capacitor. This capacitor is not installed, and the lower

pad is at Vcc when the calc is off and Gnd when the calc is

on. A transistor set up as an inverter driving a second transistor

that drives the load will allow devices to be controlled by the

calculator ON/OFF state.

On the Ti-85 the capacitor is c21, on the 86 it is c31. These

numbers may vary with the hardware version, check around

with a multimeter to verify that you have the correct location.

YMMV