My wife has a Pfaff 1540 and a Pfaff 6091 sewing machines.
She makes purses and sells them, so she puts a lot of wear and tear on these machines, and they go into the shop quite a bit. But the shop takes about three weeks to fix things, and sometimes both machines end up being out of commission at the same time, so she's without a machine. (She has other machines, but her purses require strong machines with a double stitch (?) and a walking foot (?), which the other machines don't have.)
I'm reasonably good at fixing things, and I've tried to fix her machines with some limited success. Usually she gets needles broken inside somewhere, and recently she seems to have screwed up the needle timing on the 6091.
I can figure stuff out, but general adjustment tends to escape me or take a very long time, as I don't know how it should be (and I don't really know how to sew either, so that further complicates things.) A workshop manual or something for these machines would be most helpful. Is there one available, perhaps something like what the repair place would use?