[personal] Shaft encoder in HP2631B printer

It has a number QEDS8997 on the end cover (the part that carries the LEDs). There may be a number on the other end of the housing, but I can't remove it to check, the screws holding it to the bearing plate are covered by the encoder disk that's emoxied to the eladscrew and which needs the special tools (according to HP) to remove/replace. I cna't easily provide a photo (no digital camera). If you've ever worked on HP9000/200 machines, it's similar to the encoder used on the twiddleknob on the keyboards of said machiens, but without he spindle/mounting bush. The easiest way to get to it is to go to said site, then naviage through 'printers' 'impact' 'hp2531' 'product documentation'. You'll then see a serevice manaul (and a CE manual) for the 2630B series listed. I think the encoder i nthe 2531A is similar, the one in the 2631G is very different (and, alas, looks a lot more repairable from the manual). According to the manual, this encoder was supplied as 3 separate parts. The housing, constianing the sensorts and with the cable fixed to it ; the encoder disk; and the end conver containing the LEDs. THey are fitted in that order, and removed in the reverse order. The hub of the encoder disk doesn't have a setscrew or similar. It is glued to the hend of the leadscrew with epoxy. One tool is used to remove the disk (it hocks round the hub, and a screw then applies pressure to the ned of the shaft to pull the disk off, breaking the epoxy bond. The other tool is used to bet the disk back on the spindile, it, again, fits round the hub and rests against the end of the housing, this getting the disk the right distance inside. What is not clear ffom the manual is wheter this procedure damages the disk, or whether you can refit the old one if you want to. My guessis that he other reply is correct, and that the LEDs are out. If that's the case, I may not need to remocve the encoder assembly. The end cover carrying the LEDs comes off anyway. The whould thing can be removed plate. And after doing that it's possible to unclip the cover over the cable and get to the edge of the snensoor PCB. Maybe that will be enough. -tony