My ELSA 12 now has 28 hours on it, and it is a great flying aircraft! Unfortunately, I had to replace a failed voltage regulator/rectifier about 2 hours ago. The new voltage regulator has worked well for the last two hours, producing 13.6 to 13.8 volts at cruise. Today, however, after a 30 minute flight, with flawless electrical readings, to a neighboring airport another electrical twist took place, leaving me stranded without any power whatsoever. After landing, I discovered that I could not transmit, and a low voltage warning flashed on the screen. I increased the RPM's for taxi and I was then able to transmit and the warning went away. I shut down and tied down to have lunch. After a short while, I tried to start up, but the Dynon would not power up. I noticed that the panel cooling fans were not powered, nor was did the entire panel receive power, including the electric fuel pump, trim and all other electrically powered systems. I received a click from one of the solenoids only, but no other power indications, just a totally powerless panel. Checked the battery and connections first. Battery was a bit low, 12.0, but understandably so since I had entered turned on the master a couple days ago to upload GPS data to the Dynon and we had just had a short flight, not enough time to fully recharge. We checked wiring, all okay at first check. We jumped across the starter poles and the engine turned over as it should. So, I seem to be stumped. Could this be another bad voltage regulator contributing to the failure of either the master switch or, perhaps more likely a failure of one of the solenoids? Does anyone have any wisdom with this issue that has left my aircraft stranded overnight tonight? Many, many thanks for any help from those who have experience with electrical systems!! I like to attack this tomorrow morning.
Van's Air Force
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Electrical Failure/Request for diagnosis and solutions
- Thread starter Buzz J
- Start date
This may be a simple battery failure from either an older battery or the charging system has a problem and of course not charging it.
It sounds like you have some other electrical issue and it may have caused the original reg/rec to fail. It could be just a simple wire that is chafed through, broken or not properly inserted in a pin connector. I would do the electrical trouble shooting listed in the manuals and check all my wires in the charging system.
It sounds like you have some other electrical issue and it may have caused the original reg/rec to fail. It could be just a simple wire that is chafed through, broken or not properly inserted in a pin connector. I would do the electrical trouble shooting listed in the manuals and check all my wires in the charging system.
PaigeHoffart
Well Known Member
Work your way from the battery to the fuse panel and check for voltage. It could be something as simple as a bad connection, or failed ammeter shunt. If you have good voltage at the individual fuses, I'd start looking at your ground connections.
Paige
Paige
Check both ends of the heavy wire going from the starter contactor to the AV-50001 Switch and Fuse Module. If it looks OK, then turn on the master switch and use a high-wattage 12 lamp (instead of a voltmeter) to check for power at the AV-50001 end of that heavy wire. If there is power going into the AV-50001, but nothing works, then the problem is inside of the AV-50001, most likely an open shunt like Paige suggested.
Since the new voltage regulator is putting out 13.6 to 13.8 volts, it is working fine and is not causing other parts to fail.
Since the engine cranked when the starter contactor was jumped, that means that the master contactor is working fine. The problem is either the heavy wire mentioned above or its terminals or the shunt.
A temporary fix is to jumper from the battery side of the starter contactor to the R +B terminals of the voltage regulator. In other words, jumper the two heavy wires together that go the AV-50001.
Joe Gores
Since the new voltage regulator is putting out 13.6 to 13.8 volts, it is working fine and is not causing other parts to fail.
Since the engine cranked when the starter contactor was jumped, that means that the master contactor is working fine. The problem is either the heavy wire mentioned above or its terminals or the shunt.
A temporary fix is to jumper from the battery side of the starter contactor to the R +B terminals of the voltage regulator. In other words, jumper the two heavy wires together that go the AV-50001.
Joe Gores
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Electrical problem found/many thanks for all the help
Many thanks to you guys...Paige, Joe, Roger for your sage advice! And another huge thanks to RV-12 builder, Alex E & to Wayne Flemington, Rotax guru at French Valley airport where I was stranded, who allowed me to keep N611VB in his hanger while we all worked on diagnosing and fixing the problem. After confirming all the wires, connections and components, including the solenoids and connections were good from battery, to starter, to fuse panel, to AV-50001, the culprit turned out to be a failed master switch (pics attached if I can figure out how to do that...might need someone to tell me how to do that if it is possible in this post). Alex had just received his avionics kit, so he graciously loaned me his new master switch which we installed in my panel and received a full power up, immediately, confirming the diagnosis! Whatta guy...drove to help me, then gives me his master switch! Thank you, again, Alex! I plan to call Vans tomorrow to order a new replacement master switch. I fired it up and flew my aircraft home and put it to sleep in the hangar this afternoon...more flights to follow soon. Many thanks to all of you! I plan to pursue some sort of reasonably priced, independent back up to our glass panel in the future just in case it ever goes dark again in future days/ years ahead, especially in flight...Ideas anyone?
Many thanks to you guys...Paige, Joe, Roger for your sage advice! And another huge thanks to RV-12 builder, Alex E & to Wayne Flemington, Rotax guru at French Valley airport where I was stranded, who allowed me to keep N611VB in his hanger while we all worked on diagnosing and fixing the problem. After confirming all the wires, connections and components, including the solenoids and connections were good from battery, to starter, to fuse panel, to AV-50001, the culprit turned out to be a failed master switch (pics attached if I can figure out how to do that...might need someone to tell me how to do that if it is possible in this post). Alex had just received his avionics kit, so he graciously loaned me his new master switch which we installed in my panel and received a full power up, immediately, confirming the diagnosis! Whatta guy...drove to help me, then gives me his master switch! Thank you, again, Alex! I plan to call Vans tomorrow to order a new replacement master switch. I fired it up and flew my aircraft home and put it to sleep in the hangar this afternoon...more flights to follow soon. Many thanks to all of you! I plan to pursue some sort of reasonably priced, independent back up to our glass panel in the future just in case it ever goes dark again in future days/ years ahead, especially in flight...Ideas anyone?
Driftdown
Well Known Member
Buzz,
Glad to hear it all went well and your airplane is back home.
The RV community is a great bunch of folks, with tons of experience and resources.
Roger Lee has helped me out several times with my CTSW, of which, I am very grateful.
If I didn't have my CT, I would be flying an RV-12. Great little airplane.
Glad to hear it all went well and your airplane is back home.
The RV community is a great bunch of folks, with tons of experience and resources.
Roger Lee has helped me out several times with my CTSW, of which, I am very grateful.
If I didn't have my CT, I would be flying an RV-12. Great little airplane.
This is what the GOOD RV builders do!
Here is a picture of the circuit board side of Buzz Jensen's master switch. I wonder what caused the burned circuit trace?
That is the result of passing more current though a printed circuit than it is rated for. Looks like there may be more electrical load wired into the master circuit than the switch was designed for.
RFSchaller
Well Known Member
Mike,
I don't think the printed circuit is passing the load on the bus. It's passing the power to hold the master solenoid energized. That would seem to indicate a bad circuit board or possibly an intermittent short on the master solenoid coil.
Rich
I don't think the printed circuit is passing the load on the bus. It's passing the power to hold the master solenoid energized. That would seem to indicate a bad circuit board or possibly an intermittent short on the master solenoid coil.
Rich
Yes, obviously the master switch and the associated printed circuit should only be passing the current required to hold the master solenoid coil open. The point is it may be worth looking at the wiring to see if there was a load added to this circuit that shouldn't be there, such as an external power cord for a portable GPS, or maybe even chaffed wire that is shorting to ground.
RFSchaller
Well Known Member
Mike,
Yep, a miswiring adding more load is always a wild card. I'd start with the master solenoid coil since it would be the simplest to troubleshoot.
Rich
Yep, a miswiring adding more load is always a wild card. I'd start with the master solenoid coil since it would be the simplest to troubleshoot.
Rich
Depending on the type of master solenoid, the hold coil will either have continuity to the case, or it will have continuity between two of the small terminals. Either way if it is properly installed you will have continuity to ground which makes it kinda hard to troubleshoot unless you use a meter to check the current load on the wire going into the hold coil terminal. You could also disconnect the wire from the solenoid and check to make sure the circuit is open.
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RFSchaller
Well Known Member
As an alternative to measuring coil resistance you could hotwire the coil by touching the coil terminal to ground. (As I recall the master switch is on the ground side of the coil.) Use a thin wire and it woul act like a fuse. If you hear the relay pick up it's probably OK.
A clamp on amp meter capable of reading DC current is an awesome tool for troubleshooting problems like this. Most clamp on amp meters only measure AC current, and the DC capable units tend to be expensive but I was able to find a nice compact DC clamp on meter at Sears a few years ago for less than a hundred dollars that works great.
Using a DC clamp on meter, you could remove the master solenoid coil wire and check current draw through the circuit, which should be zero or very close to it. If the amp draw is high with the coil terminal disconnected it could indicate a chaffed wire shorting to ground. If the wiring checks good reconnect the master solenoid wire to the coil terminal and check the load with the master solenoid energized, if the load is more than a couple of amps, or what the specifications for the solenoid call out, you have a bad master solenoid.
Using a DC clamp on meter, you could remove the master solenoid coil wire and check current draw through the circuit, which should be zero or very close to it. If the amp draw is high with the coil terminal disconnected it could indicate a chaffed wire shorting to ground. If the wiring checks good reconnect the master solenoid wire to the coil terminal and check the load with the master solenoid energized, if the load is more than a couple of amps, or what the specifications for the solenoid call out, you have a bad master solenoid.
RFSchaller
Well Known Member
Mike,
You are better equipped than this poor country cousin! A clamp on is a luxury I can only dream of!
Rich
You are better equipped than this poor country cousin! A clamp on is a luxury I can only dream of!
Rich
Gagarin737
Well Known Member
The RV-12 has a "AV-5000A" control module (a bit like the Vertical Power VP-X) to which all other modules (like e.g. the ignition module) are connected. The system is plug&play.
See for example the control module chapter: Chapter 42M
You can still bypass the control module if you want. The auto cad drawings at the support site are very good.
Mike,
You are better equipped than this poor country cousin! A clamp on is a luxury I can only dream of!
Rich
Yes, most clamp on meters are expensive, but for $60.00 and the ability to measure DC current, the Craftsman model 82369 meter is a must have.
http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P
That is one possibility, but considering the number of Skyview RV-12's that are now flying with no other instances of this type of failure, I think it is likely that it has a different cause.
My guess would be some type of an intermittent short on a wire that is possibly chaffing at some location.
Buzz's switch module will be repaired and sent back to him, but I am pretty confident that doing so is not repairing the actual cause of the problem. If that is not found, it is likely to happen again.
The previous failure of the voltage regulator (at rather low time in service) may be a clue of where to look, since I believe the failed pcb trace is related to the voltage sense for the voltage regulator (but I haven't looked at it yet so can't say for sure).
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