imkidd57 Posted February 15 Report Share Posted February 15 I am repairing an MDS-W1 deck, which has quite a few problems including both AMS knobs which will not work properly; there is no spring to the 'push' action and no response from the W1 deck itself to any push/pull movement. One of the knobs won't show a change on the display to rotating it, but you can feel the clicks. Thanks to minidisc.org there is a service manual, and I took off the front panel of the W1 and located the left side panel board with the AMS unit on. The potentiometer-like unit is described in the manual as a 'rotary encoder', and was relatively easy to desolder the pins and lugs and remove it from the board. With the expected lack of a direct Sony spare part, I managed to disassemble the encoder to investigate and found it irrepairable, with some of the internal parts reduced to fragments which explains why it wasn't working! Looking on Farnell's website, I think I've found a possible replacement in terms of the various physical measurements, the right pin positions and is a push-on switch, but being completely new to rotary encoders I would like some advice on the electronic digital aspects of pulses per rotation (PPR) and detente (number of clicks felt when turning the spindle). When disassembled, the original unit had a disc with radial copper stripes, of which there were 20. Can I assume that these were responsible for the pulses, as very small copper pickups - one of which was still in place in the wreckage - would have contacted the stripes and could have generated the pulses. If so, then would this be a 20 PPR rotary encoder? The number of clicks felt on another working MDS-W1 deck that I have is definitely 20 for a whole rotation, so this is should be the detente. The possible replacement from Farnell is 24 PPR (and detente of 24), so would this make any difference to the performance and suitability? I can't see that an extra four clicks would screw things up as it doesn't seem to be doing anything other than change an observable number or menu option on the display. Any advice and opinions gratefully received! Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.