See a closeup picture of the Bosch servo drives and other cabinet internals:
formatting link
I traced some wires. Wires A1 and A2, so marked on the servo motor's terminal, are power. Applying power from a separate DC power supply, to them via contacts 4 and 6 on the main terminal strip, makes the servo motor run. I only tried Y axis but it seems to work.
Wire number 4 is ubiquitous, like tarballs on the Gulf coast. Wire number 4 is present on the servo transformer, goes to all servo drives, and seemingly to all servo motors. (!)
I interpret it as some kind of "neutral", kind of like negative ground, which applies to both DC and AC (since it comes out of the transformer).
I will post some thoughts on the Bosch drives and such tomorrow. Time to go to bed.
I'm having difficulty finding A1 and A2. Are they in the "X6" terminal strip at the bottom of the board, or the terminal board at the the top right, which appears to have power MOSFETs under the board, I think to control power to the motor's armature, with terminals marked (from left to right) 'U', 'C', 'D', and 'V'?
Quite a few trimpots, now that I see it all. Several are painted with green Glyptal on the adjustment screws -- of course meaning "Leave me alone!". :-) Two of them on the small board to the upper left appear to be voltage regulator set pots, and are facing so that you can't even *get* to them unless you pull the board. :-)
The one labeled "OFFSET" on the lower left hand corner of the main board is adjusted so a motor connected to it has minimal drift (not counting the control commands which would come from the CPU). The one on the daughterboard just above it is a gain pot for the tach feedback, used to adjust the maximum speed for a full 10V input command.
Not sure what the blue one marked "STROM" is for on the same daughterboard. But the partially populated set of capacitors suggests that this is where the damping circuits are. All the rest of the gray trimpots (including the one with the vertical screw past the end of the yellow capacitor just off the tach feedback/damping daughterboard) are all green Glyptaled, so the only three pots you need to consider are the "OFFSET", "TACH" and "STROM" pots, and you can probably ignore them as long as you don't change the motors or the boards between axes.
Is that one of the ones going to the terminal strip at the bottom of the board? Most of those seem to have '4' as the first digit of a two digit identifier -- in addition to the hot-stamped three-digit wire numbers. BTW -- it looks as though that terminal strip unplugs from the bottom of the board -- wires and all. That would make replacing that board easier at least.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.