i have verified that the control card is good i have also replaced wiring for the SCR's to the control card because of flaky wiring. Problem still occuring intermittenly. The system is a SCR controlled system and has no contactors. I tested the voltage going into and out of SCR #1 When the system is working properly Scr has Battery voltage that drops to 46V and the same going out to the motor when the system is acting up i get 46V into the SCR and 40V to the motor. My question is are there any other components other than the control card that control SCR #1 or should i be looking at replacing it. Are these SCR's known to break down intermittently.

thanks
Dave