--- In Sumo11users@yahoogroups.com, "johnabshier" <johnabshier@y...>
wrote:
>
> At one level I know what I did, I let the magic smoke out of the
motor
> driver. I had a 9 volt transistor battery to power the
electronics
> (measured voltage 8.4) and a 9.6 volt RC battery for the motors
> (measured voltage 11.3). Turned on power switches; saw/smelt
smoke;
> disconnected everything. Visual inspection of L293D looks bad; no
> longer flat on top. Measured resistance across motor power leads
is 5
> ohms. Rewired power to use transistor battery for both
electronics
> and power. Ran the Sumo11 test program (IC 5.09) with no motots
> connected. With motor power switch off the led's light up in
expected
> sequence for the test. Turn on the motor power switch and the
system
> resets. I can get and replace the L293D. What else should I
check/do?
>

Apparently your motors draw a little over 2 amps (10V / 5 Ohms) and
a reasonable limit for the L293D is 0.6 amps. See VCEsatH and
VCEsatL on page 3 of http://www.alltronics.com/download/1330.pdf

And, that 0.6 amps is only valid if there is adequate heat sinking.

Richard