Replacement Encoders Found!
2011-01-27 by James R. Coplin
Rejoice! Rejoice! Rejoice! I have found an extremely suitable encoder for replacing cranky/dead ones on the Xpander. They are relatively new from Bourns. The part number you want is PEC09-2325K-N0015. Digikey and Mouser have them. They are 30 detent, 30 pulses per rotation. Rather than D shafts they have the old style knurled round shaft. The locking collets fit perfectly. Unlike most encoders, these have a nice strong detent - not as heavy as the Xpander but solid and obvious. They work a peach. The best part is they are around $2.30 in quantity 1. Buy enough for 3 spare sets and you are set for life. There are a couple of drawbacks, none of them major or deal breakers. First, the encoder shaft is long. The part comes with shorter shafts but I can't find anyone stocking them. I used a couple of washers on the bottom side of the encoder to shim it away from the PCB to the correct height. Secondly, they are small in diameter so you will need to hold them while you tighten them in place to keep them centered. You could make some kind of a spacer but I didn't bother. Thirdly, the encoders are only available with the through hole connection and not solder lugs so you have a little delicate soldering to do. Forth, the housing has a positioning tab you will need to cut off with a pair of snips so it sits flat on the PCB. Lastly, the housing is much smaller than the original encoders so will either need to solder on extensions to the existing connections or just replace them with new longer wire. Which is the correct way to go about it. James R. Coplin