Mid-production Sieg lathes using the FC250 control boards had an extra set of switch contacts that would intentionally reduce the speed of the motor when the machine ran in reverse. If your board had this 'feature' it would have a P4 terminal connected to the directional switch, in addition to P1-P2-P3 going to the speed pot.
This was removed on later production boards, and as far as I know was never re-instated on the 'XMT' series of boards. Whether Real Bull decided to add this feature back in I can't say, but I have never received newer boards in for repair that included this function. My understanding is that it was supposed to be a safety feature.
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Pete Brush (Olduhfguy)
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