Ahh crap Chris...that's just extremely poor and keystone cops running the show.
Look, I don't know Skysensor etc but would be happy to look at the HC for free...guessing its a HC issue (hopefully its just that) that'll make it "contained"...though i guess I can follow the cct and simulate it with motors (but I don't know feedback cct (motors, encoders or what ever?)? If its a mount issue...then of course ummm??? There are many types but some info is avail, it have the
H bridge drivers in the HC.
I cannot promise anything...as you know I'm an ex RAAF avionics tech that repairs G1/2's...reversed engineered the ccts and started repairs for friends...that grew. The G1 ccts I finally got (all under NDA) are ok but their G2 ccts were "poor and inaccurate to unusable". So i have experience and can reverse engineer systems. Depends they look to have sandwiched layer the PCBs and hopefully they can be easily dissembled (but makes probing ccts harder)
They appear to use 2 EEPROMs....maybe one Ra the other DEC.
So atm i can be here as your last resort if the "repairers" are finished doing their "thing". PM me or discuss here.
No promises....but i'd be happy to try...time frame...i cannot give i've been in out hospitals but i'm ok atm. I really get peeved from incompetent support ...jerks my chain my blood pressure rises! I have all the tech equipment, but of course no parts or type experience but hey who knows. If I do get it fixed, then just parts cost.
Remember no guarantees...and unfortunately i'm in Melbourne. So long distance to send.
Apart from that...i'd suggest a G11 mount cause i'm biased and repair the electronics. (also you can buy every part, nut and bolt). I prefer the older G11s not the tucked motor types as IMHO this was a poor engineering fix and their spring-loaded worm similar. Well that's my "limited" opinion but i do talk to others on this who do more mechanicals than i and this appears to be a theme. But I think Losmandy has finally fixed some of these little niggles.
Trying to say, buying a non tucked motor G11 is IMHO a good idea. If you can try get a G2 as LAN is excellent but a G1 isn't useless in fact they are excellent. Also try try to get some HiTorque motors. Yes not cheap I know I upgraded to a G2 and Hi Torque motors. Losmandy was giving a trade in for a G1 to G2...and I think still is...ask Tanya nicely. I don't fiddle mechanically much due to time constraints but an a qualified instrument maker...so can do such, its just electronics fill my day.
Anyway really sorry to hear the issues...may i also ask why it was sent? Was battery dead? Not working right?????
cheers...some food for thought
Bren
edit: oh ummm i guess you have looked at the vixen skysensor IO group...is this the right one?
https://groups.io/g/vixen-ss2k
Christopher Erickson in Hawaii appears to have parts knowledge etc to repair these, EEPROMs, Displays, parts and knowledge that i just don/t have it may be more judicial to send to him. Hate to say it,...this is what i'd do...or at least ask