PA-30 Electric Schematics

[Frank Brunot]

In the PA-30 Service Manual, there are TWO (2) different schematics for the NON-Paralleling Alternator System, Figure 11-68 and 11-68a.

1) Does anyone know which schematic belongs to which model year? I have a 1969 C model.

2) In the 11-68a schematic, there is a "box assy" in the lower left corner. What is it's purpose?

The reason for my questions is that, when turning on the Master Switch, I get no voltage to the bus bars. The Battery Solenoid works, and voltage gets to the input of the Starter solenoids. That's where I stopped and went to the schematics.

Any ideas?

Thanks.

[Kristin Winter]

Frank,

I also have a 1969 C model Twin. Mine had that box assembly mounted up above the pilot's right leg. I forget what exactly it did, but I ripped all that out and installed the Plane Power system which has been rock solid ever since. The main/aux voltage regulating system is a disaster as an overvoltage will shut both alternators off and one gets precious little warning that such has happened with the factory instrumentation.

[Russell Adair Philip]

I'm a bit late in on this but in my PA30 a few months ago this turned out to be corrosion at the next connection along in the main power cable after the master solenoid. It was where this cable connected to what looked like 2 more solenoids, possibly the L&R starter contactors (I didn't bother to positively id them after we found the corrosion, and cleaning it up cured the problem. Still up in the nose area on the RH side fairly close to the bulkhead.

Regards
Russell PA30-1771