Question: The manual mentions a "control board" and a "speed control board". Is the control board behind the push buttons? I see from the manual that the speed control board is down in the bottom of the unit near the motor.
Question: If the speed control board is bad, why does the motor spin properly when in diagnostic mode?
Follow up question/status:
I replaced the speed control board as you suggested and this did not solve the problem. The washer will not go into a spin cycle except in diagnostic mode.
I replaced the control board because this is waht the service manual suggested, and this didn't fix the problem either. When I go into diagnostic mode the unit will spin, but not in normal mode.
If I set the washer for rinse/spin, or quick wash, it will go through all of the cycles correctly. The pump will come on to drain out the rinse water, but the tub will not spin at all. After the pump runs for a time, it stops and the tub goes forward then backward a few times but never reaches spin speed.
I'm into this repair for ~ $300 and it still won't spin. Where do I go from here?