I have experienced capacitor failure with the sx's that could be traced back to a bad/poor battery.

Under regen, the battery was not able to filter the current enough, that caused the caps. to heat and then pop.

If it is an MC2 version you had previously ensure that you get the latest MC3 settings for the new part as this includes current limiting when the brake pedal is applied, along with some other improved protection features. I would suggest also asking about additional EMC protection for the machine as you have had a cap failure, which normally entails adding a capacitor to the keyswitch terminal. Although I can provide all details it is better you go through the local dealer you are purchasing the part from.

Thanks for the advise; I called our local Cat dealer. They told me the capacitor exploded; I ordered a new SX controller with the changes; they also didn't recommend the Promatch reman because of the proplems they have had.

There are a number of running changes that have been made to the SX controller and the EC30K in order to improve the system and would suggest that you spek to your local Cat Lift Trucks dealer for further advice.