For what it is worth, the capacator is in the 'power pack". (At least with the 60 CT1). Place your ahd on the power pack and fire the flash at full power and you can feel the capacator working, as if you were to thump the case from the inside.
My suggestion the power pack is low cost enough from KEH just get te new power pack. Once you get bit by the chared capacator the power pack will be a bargain.