If you have a US Tower crankup that sometimes refuses to move, you may
enjoy the following trouble-shooting tips. YMMV since some control boxes
may be different from mine, but this is what I learned from their
electrical expert:
Inside the control box on the tower, there are up/down relays on either
side of the main power relay. These are above the white time delay
relays. On the outside of each relay is a little plastic button. Depress
that button to energize the motor directly, bypassing both the time
delay relay and the limit switch. If you have a problem with the time
delay relay or limit switch, this will work. If you have a problem with
the up/down relay or the motor, this won't help.
If you have a remote control, you can take it out of the circuit as
follows: Disconnect all seven wires from the remote control. Connect a
spare AC pigtail with hot (black or red) to C3, neutral (white) to C4
and ground (green) to ground. (I don't see why you couldn't do this with
jumpers off the main power terminals, but the electrician described a
separate pigtail.) Connect a jumper from C3 to C6. If you have a problem
with the remote control box or its cable out to the tower, this should
work. If the problem is at the tower, this won't help.
Safety precautions: Disconnect all power while making these connections.
Simulate time delays when using the up/down bypass pushbuttons to avoid
reversing the motor too quickly. Be careful not to touch the terminals
of the up/down relays when reaching around to push a bypass button.
Observe all the usual precautions for working with towers and power
circuits.
No, I have not solved my intermittent tower-won't-move problem. When the
electrician called, it was working all by itself after 24 hours of
futile efforts. But the next time it fails, these hints should help me
figure it out.
73,
Rick N6XI
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