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L298 Overheating issue


First, i'm not very good at electronics/hardware (i wish i were, but i'm more of a software guy)..so please bear that in mind in case i say something really stupid.

I'm hoping someone can advise me on how to debug a hardware issue i am having with a controller based on the L298 chip. The problem i'm having is one where the motor is overheating, to the point where at one time it started to smoke.  When i retried hours later, the controller still seemed to work, but it would only drive one motor forward.  

As a simple test, i unplugged everything and only connected a 9.6v nimh battery to the controller.  With just this, the chip on the controller got extremely hot.

Can anyone think of what may be causing this? Are there steps i can take to 'debug' this?

The controller is this: http://www.ghielectronics.com/catalog/product/315

And the motor specs are as follows:

Rated Input Voltage: 12 Volts
No Load Speed: 175rpm
Gear Reduction: 1:40
Stall Torque: 125 oz-in (9 kg-cm)
Weight: 4.7oz
Motor leads: 12" long 28AWG
Quadrature Encoder leads: 12" long 28AWG with 0.100 Header (Encoder Adpater board: +5V, Gnd, Channel A, Channel B)
Pulses: 480 Pulses per output shaft revolution
Drive Shaft Diameter: 6mm
No Load Current Draw: 130mA
Max Current Draw (Shaft Lockup): 1.5A
Wiring Specifications

Motor Power Supply Wire: Vcc Power In (0 - 12 volts)
Motor Power Supply Wire: Gnd Power In
Encoder Adapter Board Vcc: +5V to 12V
Encoder Adapter Board Gnd:
Encoder Adapter Board Channel A (0v-5v out)
Encoder Adapter Board Channel B (0v-5v out)

Thanks much for any advise

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Hi kingart3,

i was very careful to make sure that wasn't the case.  Also, the motors were running fine for a while..but later stared to behave irratically...for example one motor would run when moving forward, while both would work when moving backwards.