Low voltage on MEP 803a

[Chanderson69]

Hello all. New to this group with some experience with military generators. I recently purchased an MEP 803a from gov planet. 2007 with tier 2 reset done in 2011 with 220 hours. The unit is only producing 50-60 volts on the L1 & L3 lugs. If I flash the field it produces the normal 220v 60 hz As soon as I let go of the starter switch it returns back to the 50-60 volt range. Also only 28volts out of the receptacles. I can’t imagine the regulator is bad if it shows normal readings so long as I hold the starter switch in the crank position.

 

[kloppk]

Most likely a bad AC Voltage Regulator. You should test per the -24 TM to be sure.

 

[Light in the Dark]

I would agree, sounds pretty classic dead VR. Kurt (the chap who responded to you) makes an awesome upgraded VR that you will never have to think about again.

 

[kloppk]

... I can’t imagine the regulator is bad if it shows normal readings so long as I hold the starter switch in the crank position.

The reason proper AC voltage is present with S1 in START is that the set is "Flashing" the gen head to kick off generation.
Flashing is NOT done by the AC Voltage Regulator. It's done by other components behind the gauge panel.
When you release S1 back to Prime/Run the AC Voltage Regulator is supposed to take over and maintain the AC Voltage.

 

[Ray70]

Does your machine have the quad fuse mod. to the left of the regulator?
If so, test the fuse. If not, install the fuse mod before going further....

 

[Guyfang]

If you do not know what a Quad fuse mod is, do ask.

 

[kloppk]

Quad Fuse Mod circled.
It gets installed on the back wall behind the gauge panel just to the left of the A1 AC Voltage Regulator.
Fuse should be a FNQ-R-3 instead of the KTK-3 in the picture.