I did pull the end panel off of the 834. You can see where the guts behind that large knob are moving. The tiny knob inside the large one pushes in and out. When you do that, it moves the feed dogs. more in a forward and back way, than any up and down.
It is hard to see everything in there, because of the handwheel.
I have errands to run today, not sure how much 'tinker' time I will get. My mil's husband died this week, and his services are ALL day tomorrow. ugh. luncheon 12, receiving 1, service 2, burial 330. He'd had dementia and been in a home for a while, so we aren't sad (mil isn't really either!). definitely going, just hate to lose that day! =//
something good has to happen soon, right? cold today, raining tomorrow and sunday . . . Spring, where are you?!