[TowerTalk] Troubleshooting HamIV rotor and controller

[Gary Slagel]

Hi guys,
I have a HamIV rotor that's 4 or 5 years old and a companion controller that has an aftermarket brake release delay installed on it.   Yesterday the rotor quit turning.  When I turn on the rotor control the light comes on, the needle swings to the far right which is right where the rotor is turned to. 
I've checked the fuse and its good.  I've been through the HamIV manual troubleshooting section and measured voltages and resistances and come up with the following anomalies:
With controller plugged in and powered on and all terminal wires removed:        manual says the needle should remain on the left hand S but mine swings to the right
        All other voltages described in manual look good except terminals 3 and 7 should show 13VDC but show zero

With controller unplugged and terminal wires removed:          Resistance across line cord is 4.5 ohms with brake lever depressed
        All other resistances seem consistent with troubleshooting suggestions except they are low (1.5 instead of 4)

Resistances measured on the control cable:       These all seem reasonable compared with where the manual says they should be except the resistance across the entire pot switch (term 3 and 7) is 290 instead of 500.   Resistance across Pot Arm to +end and -end total 290 ohms at 1 ohm and 289 ohms.

Just hoping someone might have an idea where to look next.   My next idea is crank down the tower, look at connections and listen for noise when hitting the brake and turning levers.   Next, beam off and rotor onto the bench to see if it works with another cable.
Thanks for any thoughts
Gary SlagelKT0A