I'd wager your issue is caused by USB cable. for some reason, the AAP & Celestron mount HCs don't like most USB cables. I went through 7 straight cables all having random failures. I bought a $10.00 quality shielded gold USB cable and haven't had an issue for over a year. I went back and tested all those cables again and they all failed with AAP but work fine for computers and such.
not sure why. but you need a proper shielded quality cable or you will get issues with Celestron mounts. I've mentioned to others with AVX issues here and on other forums and they also reported a good cable solved their problems.
I didn't bother to look beyond it once things were working for me, but I've heard that there are a bunch of wires inside the USB cable, and depending on quality, some wires are not used, e.g. extra grounds, some cables only carry charging wires and are missing some/all of the data xfer wires, likely this is it - cheap cables cutting corners on the wires and on garbage connectors which the USB mini cable is terribly designed and in cold weather has seating issues with the pins in the HC. I also think the Celestron HC is garbage parts, I've opened mine up and it's something from the 90's with low quality components poorly put together. all this adds up to not being a reliable connection.
I'd also wager that because the AAP communicates via serial @ 9600 baud there is no error correction and with a crap cable even a single bit dropping can wreak havoc... it's not actually using native USB connectivity from what I understand.
the next step is Celestron updates, first do the HC update, that is a lot safer. the motor controller likely also has an update but that is a bit more risky as any issues and it can brick the mount, it's not likely the motor controller is the issue, it's more likely it's the HC. you can get the latest downloads from Celestron's website.
