PS!
If anyone's following this thread and can't read the horrible scans of the circuits in the original 175 Manual this revised one, called "Rev C", has much better diagrams in it:-
https://www.industrialcalibration.co...n%20Manual.pdf
I've printed 'em out for study to assist further if need be!
I think the differences will be only insignificant, mainly in the mains connector, backlighting & software rather than a major physical - difference - the basic topology between the drawings looks identical to me!
Chris Williams