Voltage Regulator for 252

[jackn]

My dual alternator voltage reulator just died. Mooney doesn't have one in stock and would need to build one custom. The Part # is Mooney 800270-503. If anyone knows where I can find one, please let me know. My avionics tech & I are calling around to the MSCs. Thanks!

[KSMooniac]

Does Zeftronics make a replacement?

[Parker_Woodruff]

Jack,

Have you checked with Don Maxwell?  He always seems to have good answers on this stuff.

You and me both facing alternator and charging related issues.

[AndyFromCB]

I assume you have dual alternators.

Are you sure it's dead? What's happening? If it's dead, talk to Maxwell, he seems to have some kind of direct connection to Zeftronics. They won't touch it directly and it will take months to get one thru Mooney. Don charges $250 flat fee for these.

But before you decide it's dead, tell me what's happening. There is actually two separate voltage regulators in the box so I'd be a bit surpised if both died at the same time. Now, one is always asleep, slaved to the other one. Have you tried swapping the two plugs? What happens then? If you're going over voltage or poping ALT field breaker, try disconnecting one lead at a time and then swapping them side to side. You might have a problem with field sense wire/connection and not the voltage regulator. Most A&P really do not understand electricity so you can spend a fortune tracking these things, ask me how I know.

Also, plane power makes PMA voltage regulators for Mooney with a slaving option. I don't know if M20K is on the PMA list but if it is then it's an option. It's not an option for my M20M but I have one prewired sitting in my passenger side pocket anyway just in case. If you get the plane power unit, you'll need to order new plugs, mouser.com is a good source for the 9 pin plugs.

[jackn]

Excellent comments. My avionics guy spoke with Maxwell, with no luck. They only made a handful of these VRs. Checked with Hartzell Engine Tech(bought Electodelta) & Zeftronics with no luck. Mooney has different part #s for the 28v Dual Alt K, Bravo, Ovation. Is it the pinouts? Who knows. Andy, it was just one, as you guessed. One was already changed to a single alt unit. Someone opened the box & added a wire and a diode. The remaining original factory VR is the one that went bad(we swapped VRs). I just want to bring it back to original. Checked the field wires, they are known to chafe and short. Not the case here.

I found one(or two as is the case). One side is currently inop, but is is being refurbished and will be shipped to me with new tags.You would think a 28v VR is a 28v VR and that I could just call Zef and be done.

[jackn]

Parker, What's going on with your charging system? BTW, changing the #1 Alt is near impossible, but can be done. Ive done it twice.

[Parker_Woodruff]

Coming out of annual in April the coupler broke. Then last month the #1 alternator ate itself alive internally.

[jackn]

I keep a spare #1 with me just in case. The best way to replace it is to remove the oil filter, then the the oil filter adapter(3 bolts). Good Luck

[KSMooniac]

Quote: jackn

Mooney has different part #s for the 28v Dual Alt K, Bravo, Ovation. Is it the pinouts? Who knows.