This is the third part of my series on my experiences while repairing electric and electronic devices. Here’s the second part. This repair concerns a proprietary cable connecting the remote control of an electric wheelchair with the drive control. The wheelchair was out of warranty and the repair shop in question quoted 400 € for the cable alone. With the service call charge and billable labor on top, the total cost would have easily exceeded 1000 €.
Taking a closer look at the remote control unit’s connector receptacle showed that it contained only four signals. Further analysis yielded that the joystick and buttons of the control unit were read by a Microchip PIC microcontroller and transmitted to the drive control unit.
I found out that I could replace the proprietary cable and connector with a standard industrial 4-pin M12 cable. The cable plus connector came to about 40 €. After removing the proprietary receptacle and enlarging the mounting hole by about a millimeter it was fairly easy to shoehorn the new M12 receptacle in.
Below you can see the complete remote control unit, with electronic components and the replaced connector clearly visible.
Reassembly was a bit tricky, as I had to be careful not to pinch any of the cables (especially the thin ribbon cable connecting to the push buttons on the device’s front). After a brief test, I returned the wheelchair to its owner. There’s no design improvement lesson here, but I wish manufacturers would use less exotic cables to ease the repair and replacement.