Yes Elm, unless the micro switch is bad on the board, MDO and MDC typically work even with bad comm. the exceptions for this are, software, and board issues unrelated to power (encoder, dcl, dol, etc.)

For everything I have ever thought I had nailed down to a single problem... Let's just say there is a reason I now carry multiple solutions, lol. These are just the most common for me being a NI adjuster, some may not translate well to the service world, because at the very least you all know, it used to work right.