I have an older jugs machine with the digital speed screen. When I turn it on it starts spinning and getting faster then it cuts out starts slowing down then cuts back on. It continues this cycle. Does anyone know what the fix is?
They are a pretty simple set up minus the board... You may want to check for loose connections. One the machine gets up to speed there is some significant vibration going on. Next thing I would do is pull the board and look at the solder joints. Could be a weak joint. A quick and easy repair. If it's not the above then it could be a component on the board. Pull out a multi-meter and start tracing.
Check the compression nut below the knob. I had one doing this, and tightened up the nut. The potentiometer that connects with the control board flexes sometimes and causes the speed to drop out. Good luck.
My initial thought is the speed adjustment potentiometer as well. As a general rule, they wear out fairly quickly for the amount of use that they get. When they do wear out, they act exactly the way you're describing.