I have a model 6000SL that initially would only sew in reverse the dealer says the camm is jammed and he cannot repair it without the risk of doing serious damage to the machine although it is now doing forward stitching I dare not risk trying reverse in case it goes wrong again can you help ?

SOURCE: reverse sewing button stuck HELP!!

MOdel 6430 has the stitch length and buttonhole selector on the same knob. It is the one on the bottom right side of the machine. I believe you may have selected the buttonhole by pulling out on the large round knob. You need to turn the knob back to 0 zero and push in. This should return the machine to normal mode.Adjust your stitch length to 3 and try it. The reverse knob in the center should also stick out so that it becomes operational again.
sewman7

SOURCE: needle stuck in right position, will only sew tiny,tiny stitches

oil it. down the shaft if you can get to it. and where ever there is a hole it always helps.

SOURCE: Viking sewing machine model 6430 will only sew backwards

Th cam stack gears have gummed up on you you can try getting the back cover off along with the side and soaking the machine down with wd-40 and running it while forcing the reverse button in and out if it breaks free try and soak up as much of the wd-40 as you can and then oil anything that moves. I know this may be discouraging but viking no longer supports this machine and you might be better off taking it to an older viking dealer for help.

SOURCE: My model 210 is stuck in reverse. Can you help?

The only thing you can do to possible free the mechanism is to turn the lower dial back and forth a bit, from the position where it is in permanent reverse to the numbered area on the dial. Make sure the selector is not on the buttonhole position. That machine doesn't really have a history of that issue but anything is possible, especially if it has sat for awhile and not been used. If moisture was present where it was stored, it's possible the feed linkage is slightly rusted and simply stuck.