Several suspects in order of where on the line they are
First: the Shut-off valve and optional inline filter (Closed/Clogged)
Now the switch on the U-matic *1
The solenoid
The line from the solenoid to the icemaker
Iced up
1: Hook a 120 volt test light to the solenoid leads (you can pull 'em off while unplugged and hook 'em to a test light) have someone force cycle the ice maker by turning the big gear wheel in the direction of the arrow.. if the light comes on and goes off the ice maker itself is good.
Next hook it back up and again cycle it.. If water water everywhere but not a drop of ice.. Tub is broke.
A flat metal piece (Key. knife) that magnets stick to held near the solenoid (like 1/4 inch away) while the ice maker cycles should be attracted to the coil at some point, make sure it's flat to the coil or you should hear the "CLICK" as the valve opens.
NOTE: Solenoid valves vary in cost. from under 10 bucks to over 50, and nearly all of them are interchangable.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times