What manual is the -34 manual referred to by speddmon for testing for the cv/cvt. Thank You!
That would be TM 5-6115-585-34.
In case you weren't in the Army and had the short course on TMs...the first digit is the branch. 9 is ordnance. 5 is engineering etc. The second series of digits is the federal supply class. 6115 is generators and power, this corresponds to the FSC on the national stock number/federal stock number or NIIN. The third series is the sequence, 585 is the 003A. The final digits are the level, -10 is operator, -20 is organizational maintenance, -30 is direct support, -40 is depot. Some TMs are condensed, like in this case there are the -12 which is a -10 and -20 together. The -34 is direct support and depot. Finally, there is the parts manual, sometimes also broken into levels like a -20P. This generator has a -24P.
Oh, there is also the lubrication order LO-5-6115-385-12.
Search for MEP-003A generator
As far as your problem, I would get the -12 and trace the wiring. Since the voltmeter is in the control cubicle while the current-voltage transformer is in the output box, you have two connections. These are called Cannon Plugs, not because they are used on cannon but were patented by a guy named Cannon.
There are two or more rings which are threaded on each Cannon plug, to disconnect, unscrew the largest ring. The smaller rings are used to squeeze down a silicone rubber grommet to make the connection waterproof. But they CAN leak and corrode. Most are silver plated but some may be gold. Silver corrodes. Solder joints break. Fortunately, all parts are available. But servicing them is beyond scope of this post...just find the problem and report back.
Now it COULD be a problem with the meter itself, if you are getting voltage to the meter. Since you have a working generator, you could try swapping.