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Old 04-09-2023, 10:06 PM
ChuckC ChuckC is offline
Join Date: Apr 2011
Location: Meridian, ID
Posts: 85
Default No Electrical Power

RV-12, Serial Number 120445, with 912ULS Rotax engine; Dynon: with D1000 EFIS, A/P, ADSB In/Out, GPS2020, Transponder, Pitch and Roll Servos; and, Garmin: SL40 Radio.

Engine starts and runs fine. Dynon EFIS comes alive.

There appears to be no power to the A/P, ADSB In/Out; Dynon GPS2020; Dynon Transponder; Dynon Pitch and Roll Servos; and, Garmin SL40 Radio;and, all the switches from the Trim Switch thru the AutoPilot. All the fuses are good. Engine battery is two years old, appears to be holding a charge and turns the prop easily.

Looked under the cowling and in the avionics bay, and, found no mice or birdís nest. Looked for loose connections and abraded wiring, found none.

Plane was last flown in late November and was flying properly at that time. It has sat in a hangar from December thru March because of the snow and cold weather. Now, a bunch of stuff is not working. I am not an electronics wizard. Any suggestions would be appreciated.
Chuck Carlson
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Old 04-09-2023, 10:31 PM
JDA_BTR JDA_BTR is offline
Join Date: Dec 2013
Location: Colorado Springs, CO
Posts: 1,553

Is there a relay for avionics?
Ser 140142, RV-14A flying - N1463
Ser 83825, RV-8 building - N8638?
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Old 04-09-2023, 11:16 PM
RFSchaller RFSchaller is offline
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,390

I assume your fuses are OK?
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Old 04-10-2023, 08:34 AM
DHeal DHeal is offline
Join Date: Sep 2006
Location: Windsor, California
Posts: 1,044

Avionics Master switch internal failure or associated wiring? You can look at the overall wiring diagram for your version of the RV-12 on Van's Aircraft's website at:
David Heal - Windsor, CA (near Santa Rosa)
EAA #23982 (circa 1965) - EAA Technical Counselor and Flight Advisor; CFI - A&I
RV-12 E-LSA #120496 (SV w/ AP and ADS-B 2020) - N124DH flying since Feb 2014 - 1,290+ hours (as of May 2023)!
VAF donation through June 2023.

Last edited by DHeal : 04-10-2023 at 08:39 AM.
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Old 04-10-2023, 01:48 PM
Mich48041 Mich48041 is offline
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,512

Switches need exercise just like people do.
Turn the avionics switch on and off 100 times to wear away the corrosion.
Joe Gores
RV-12 Flying
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Old 04-10-2023, 04:20 PM
jmra72a jmra72a is offline
Join Date: Oct 2010
Location: Kalamazoo, MI
Posts: 61

Is your plane equipped with the Advanced Control Module? If so, you should be able to access it through the Dynon EFIS to see what is alive and what is not.
Bill Wilson

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Old 04-10-2023, 04:26 PM
Piper J3's Avatar
Piper J3 Piper J3 is offline
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,923

Could very well be like Joe says – corrosion. I’m finishing annual condition inspection after plane sat in hanger all winter. See my post Weather has been dry for a week and I powered-up plane today and everything looks hunky-dory.

I hate moisture on electrical stuff…
Jim Stricker - EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 850

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father - CFI) - USAAF 1st Lt. Captain B-17H
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Old 04-10-2023, 09:00 PM
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rcarsey rcarsey is offline
Join Date: Jul 2012
Location: North Brunswick, NJ
Posts: 439

It almost sounds like the avionics switch itself is broken.

I've had two Otto switches fail internally -- one time the switch "felt" different when using it.. the other time, I couldn't tell from the outside. In both cases though, it was due to a short circuit and the switch's contacts welded themselves to a contact pad.

I'd check to see if you have power at the switch..and if power is getting through the switch when activated.
Rob Carsey, Winfield Park, NJ
RV-12iS (N713) / Completed 12/2020 / 350hrs and counting
APRS Track or ADSBExchange Track
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Old 04-10-2023, 11:31 PM
rvbuilder2002 rvbuilder2002 is offline
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 10,187

I am pretty sure the auto pilot servos do not source power via the avionics switch, so if they actually are not receiving power, that would point towards some other cause.
Opinions, information, and comments, are my own unless stated otherwise.
You are personally responsible for determining the suitability of any tips, ideas, etc. obtained from any post I have made in this forum.

Scott McDaniels
Hubbard, Oregon
Formerly of Van's Aircraft Engineering Prototype Shop
FAA/DAR, A&P, EAA Technical Councelor
RV-6A (aka "Junkyard Special ")
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Old 04-11-2023, 01:09 PM
Tommy123 Tommy123 is online now
Join Date: Jul 2018
Location: Naples fl
Posts: 370

Corrosion. Check the fuses if you have any. My car shut itself down the other day, it was corrosion in the "engine" fuse.
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