Lots of people get machines second-hand, which need some TLC, and they don't know what things are supposed to look like on the underside. I thought I'd post pictures of some of my carriages in the hopes it might help diagnose faults. These pictures are of the KH260, which has the split-button / punch lace feature. Note that these are just pictures of the cam buttons being pressed - in order to make the patterning read from the punchcard, KC or SM would also need to be pressed (see later pics). As always, click on the picture for a clearer view.
Needles in A (Non-Working Position)
Needles in B (Working Position)
Needles in D (Upper Working Position)
Needles in E (Holding Position)
This is the underside of the carriage set for N or stocking stitch. Note that any needle in HOLD (the blue line) will knit back.
This is the carriage set to tuck - note that needles in B don't move out as far (ie they tuck). Needles in D and E position knit.
This is the carriage set for fair-isle. Needles in B position take a slightly shorter route and knit the yarn in feeder A. Needles in D or E position knit the yarn in feeder B.
This is the carriage set for punch lace - this is a very similar set-up to the fairisle one. Only later machines have this function. Both yarns knit together in certain areas, and the second yarn only knits in other areas.
This is the carriage set to slip - needles in B position hardly move and therefore do not knit.
This is the carriage set to hold - any needle in E position will remain in E position.
This is the carriage in N position. Note also the pink plastic part - this is the end needle selection cam. It's not always pink though, sometimes it is yellow.
This is the carriage in KC (Knitting Card) position
This is the carriage in SM (Single Motif) position - not available on all machines.