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On question#2:

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? Most likely, the tiny setscrews in the Oldham Coupler of the DEC axis are loose, so the motor is running, the gearbox is running, but the worm is not.

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Remove the black metal cover over the worm, and examine the Oldham coupler.? The most likely wrench to use on the setscrews is a 0.050 inch Allen Hex Key wrench.

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There are two setscrews per metal end of the Oldham coupler.? Be sure to tighten all 4 screws.? You should check the RA axis coupler too.

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And be sure to lubricate the worm with a good quality molybdenum disulfide ("Moly" or "MolyD" containing) grease.? Auto parts stores normally have these type for brakes or bearings.

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In the USA, I get CRC Brake and Caliper Grease.? It may not be available everywhere in the world.

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At this same time, look at the white plastic middle of the Oldham coupler as the worm is rotating.? ? When the worm turns, that white middle is only supposed to rotate, not shift up or down or in or out.??

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The upper photo attached shows a badly aligned gearbox and so the coupler middle is clearly too high.? You must adjust the position of the gearbox to get that white center to only rotate.? The shift of the Oldham coupler is associated with periodic error.? It is tolerable on the DEC axis shown here, but not acceptable on the critical RA axis where it creates PE.

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No idea how to find the cable you desire in question #1. You will likely have to make that cable yourself.?

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Best of luck,

Michael

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