[amsat-bb] 5400B Rotor Problem

[Bill Bruno]

First, many thanks to W7PN, VE4YZ and W0SAT for their help in 
troubleshooting my rotor problem.
Problem: Both az and el indicators moved to just past the mid position with 
the rotors  moving full travel ( They moved all the time the rotors were 
moving but at a slower rate).
Both indicators have the same circuitry differing only in the scale on the 
face plates so  all voltage readings should be the same for both az and el. 
Mine were.
On the back of the controller, terminal 1 should read a constant 6 vdc. 
Terminals 2 and 3 voltages will vary according to rotor position but  added 
together should total 6 v.
My terminal 1 reading was 3.2 v, approx half what it should be.
Following  the circuit back towards the voltage regulator, R9 and R10 also 
both read 3.2 v ( should be 6 v). At the voltage regulator (Q2 on the 
diagram, Part # ua7806c) readings should be approx 16 v on the input pin, 6v 
on the output pin, with the center pin ground. My readings were 16 v in, 3.2 
v out, center pin ground, isolating the problem to the voltage regulator.
I hope this info can be of use to others.
Bill KB2RC
Amsat 6986