It's highly unlikely your CP4 died.
You had a motor stall. Possible poor connection of your motor cable. Possible poor connection to your power supply.
From: Cheng-Yang Tan via groups.io <cytan299@...>
Sent: Sat, May 29, 2021 11:36 pm
Subject: [ap-gto] My AP1100 CP4 died (I think ..., need confirmation)
I think my AP1100 CP4 died this evening. The first symptom was that my CP4 wasn't recognized with the USB connection. But I could talk to it via TCPIP (my backup). But APCC couldn't move the DEC. It gave the error message in APCC shown in the attachment. I thought it could be the latest Win update, USB port, USB cable, bad motor cable, Power supply etc. I checked that the CP4 module LED was lit red (and it was). I power cycled the CP4 a few times to be sure that it wasn't hung up on something. That didn't fix the problem.
After two hours of monkeying around, I gave up and brought everything back inside. Since I have a Mach1GTO with its CP4, I used the same USB cable, power supply and computer to verify whether any of them were the problem. These tests showed that the same computer, USB cable and PS worked with my Mach1GTO CP4.
So after the Mach1GTO tests, I wanted to test the AP1100 CP4 again. But this time the LED didn't light up.
Well, I guess the CP4 must have died a slow painful death :( Is there anything else I should or can test before I ask for an RMA to ship it back to AstroPhysics for repair?