I was having an issue with my Farmer machines. A servo on the Farmer pulled items out and sent them to a Black Hole Unit. This worked so long as the Farmer's output slots did not fill up. If they were full, it was as if the servo jammed and it wouldn't send. The temporary fix was to pull a stack out and it would work again. Of course this required frequent tending and didn't solve the root problem.
By some good fortune and simply playing around I found a solution.
Instead of sending the items to a BHU, if I send them to a chest and then servo the chest into a BHU the issue goes away. By observation in my itemducts I can see the servo sends to the chest much, much faster than to the BHU. This prevents the Farmer's output slots from totally filling. Likewise the chest servo apparently spits the items out just as rapidly to the BHU.
The root issue is really not solved, namely the Farmer/Servo/BHU interaction. But sticking a chest in the line works for me.
