Oops.
The 737 stabilizer trim motor is much more sophisticated than I had envisioned. I've attached a brochure from Eaton's plant in India. It's a three-phase motor, with an internal processor that monitors commutation and speed. It is a fully digital unit. Fault codes are stored in a non-volatile memory, and can be extracted using RS-232. It lools like there are two 9-pin plugs for signals. There is no way this motor and control system was used on the original 737s.
YYZjim
PS: It look like the manufacturer's testing has identified solder joints on the memory chip as the most likely point of failure, but that does not mean there have been any failures in use.
Last edited by YYZjim; 1st Jul 2019 at 01:15.
Reason: I see MemberBerry already noted this.