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No Joy with Diagnosis of Negative Amps & Declining Volts

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Well Known Member
My RV12 is equipped with dual Dynon Skyview HDXs ("SVs"). Until recently, the Amps and Volts displayed on the SVs were exactly what they were supposed to be. Now though the SVs display negative Amps -- anywhere from -4 to -12 Amps, depending on how many of the plane's components I've turned on -- and declining Volts.

The plane has a Rotax 912ULS engine, and many planes with that engine have this identical battery charge issue. My mechanic has done all of the things recommended in other threads here on VansAirforce.net
- He secured the connections to the Ducati Rectifier/Regulator.
- He replaced the Rectifier/Regular with a new one, because the old one had blisters on its back.
- He tested the voltage output of the stator and of the new Rectifier Regulator, both of which were what they should be.
- He improved the grounding of the Rectifier/Regulator by sanding the firewall to which it is bolted; and he added a ground wire attached to the battery's negative terminal.
- He changed the Rectifier/Regulator again, in case the first new one was defective right out of the box.
- He charged the plane's Odyssey PC680 battery. And I replaced that battery with a brand new Odyssey PC680 battery.

None of these things helped. The engine starts immediately and runs smoothly. But:

- The Skyviews still display negative Amps and declining Volts.
- Also, both SVs turn on as soon as the Master switch is turned on, but after just a few moments, the co-pilot side SV blinks off and reboots.
- Finally, the digital checklist I added to the SVs no longer stays on, the way it used to. Now, after a short time, the checklist blinks off and is replaced by the moving map (which is the default item for the right half of my displays).

The only change to my Skyview setup that I've made is that shortly before the battery charge problem began, I installed Dynon WiFi Adapters. They worked fine for a couple of flights, and then my iPad Mini began dropping the WiFi signal.

I now wonder whether my problem is with the Dynon Engine Monitoring System, rather than the plane's charging circuit. That is, I wonder whether the failure of the old Rectifier/Regulator -- or something else -- damaged the circuit that senses, reads and displays Amps and Volts, so the SVs now erroneously display negative Amps and declining Volts.

Any thoughts about what my problem might be, or what to do next, would be deeply appreciated. Right now, I'm the stressed owner of a handsome assembly of used airplane parts, without a clue about what I can do to turn those parts back into the wonderful airplane it used to be.
 
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I'm hazarding a guess here, but I believe you should try and disconnect one of the Dynon HDX screens completely, and just run one screen, and see what you get for Voltage and Amps.

Short of that, ask Dynon what the voltage and current draw is for each HDX unit., and what you have running in the backround.

The HDX, I believe is rated for up to 30V, on a 24V system, so current spikes doing damage is probably highly unlikely. However, the lower the voltage you run, the higher the current or amps you draw. You need at least 22 gauge wire for wiring, per unit. I'd be inclined with the current you are pulling to go use 20 or 18 ga to power the HDX units from the Main circuit, and make sure the wire gauge is heavy enough to cover what's being demanded from the Ducati VR. it's known to only be capable of perhaps 16 amp draw charging rate... Keep in mind, this is a motorcycle voltage regulator, it's not for running Skyview screens, lcds, back lights and cooling fan motors for each unit to keep the computer parts cool.


Can you turn the daytime brightness down on each of the HDX units and see if it draws less current?

Other than that, I am out of ideas. Is the wiring gauge from alternator to voltage regulator to the main buss and to the HDX units an adequate gauge? I know previous posters have stated, at least with the earlier Skyview 1000 Touch that the Rotax alternator couldn't run two panels.

Do you have Auto pilot turned on? Can you de active it or turn it off?

Look at pages 2.2 through 2.5, to calculate your current load. The Auto pilot and servos take a good chunk of juice.

https://dynonavionics.com/public_ht...ystem_Installation_Guide-Rev_AC_v15_2_002.pdf


Worst case, you might have to just settle for only one HDX unit in your bird, or get an additional alternator and Ducati VR to make enough voltage and current to keep up with demand.

Or yank the WiFi adapters?
 
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If you have negative amps and declining voltage your system is not charging.

To troubleshoot the system we need to start here. With your meter on DC volts, what is the voltage at;
1) Regulator ?C? pin
2) Regulator ?R? pin
3) Regulator B+? pin
4) Battery positive post
Measure these voltages referenced to ground with the master switch ON and the engine stopped.
 
Also be sure to check that the spade connectors are tight on the voltage regulator.

They can get loose and need adjustment to "bite" the spade lug properly for continuity. Time and vibration can loosen them up.
 
I had a problem with another homebuilt and needed to figure out whether it was the idiot light or the voltage regulator. I rigged up a temporary digital voltmeter and went flying. I was looking for around 12.3vdc with alt switch off. And around 14.4vdc with the alternator on. Turned out the idiot light was correctly indicating an overvoltage condition with 15.5vdc on the battery bus under high RPMs. And, I had a failing voltage regulator.

Hope this gives you some ideas.
 
If you have negative amps and declining voltage your system is not charging.

To troubleshoot the system we need to start here. With your meter on DC volts, what is the voltage at;
1) Regulator ?C? pin
2) Regulator ?R? pin
3) Regulator B+? pin
4) Battery positive post
Measure these voltages referenced to ground with the master switch ON and the engine stopped.

With the engine off, the electric fuel pump off (i.e., the circuit breaker removed), and the avionics off, I got these readings on the multimeter:

With both Skyviews on and the Skyview showing 11.9 battery volts:
C 1.18 volts
R 11.9 volts
B+ 11.9 volts
Battery 11.94 volts

With only the pilot-side Skyview on (co-pilot-side off) and the Skyview showing 12.00 volts:
C 1.16 volts
R 11.98 volts
B+ 11.99 volts
Battery 12.00 volts

With the engine off, I also measured the resistance between the two yellow wires that plug into the G pins; and, after several moments of bouncing around, the multimeter showed a resistance of 0.2 ohms. There was no reading between each yellow wire and a ground.

With the engine off and the avionics off, the Skyview displayed these readings.
With the electric fuel pump off (i.e., the circuit breaker removed)
-4 amps with only the pilot-side Skyview on,
-5 amps with both Skyviews on,
-6 amps with both Skyviews on and the Dynon WiFi Adapters plugged.
With the electric fuel pump on (circuit breaker plugged in)
-7 amps with two displays on and the WiFi Adapters plugged in.
 
Also be sure to check that the spade connectors are tight on the voltage regulator.

They can get loose and need adjustment to "bite" the spade lug properly for continuity. Time and vibration can loosen them up.

I watched my mechanic do this. He added one new connector, and tightened all of them very carefully.
 
I had a problem with another homebuilt and needed to figure out whether it was the idiot light or the voltage regulator. I rigged up a temporary digital voltmeter and went flying. I was looking for around 12.3vdc with alt switch off. And around 14.4vdc with the alternator on. Turned out the idiot light was correctly indicating an overvoltage condition with 15.5vdc on the battery bus under high RPMs. And, I had a failing voltage regulator.

Hope this gives you some ideas.

I too had a failing voltage regulator, but my mechanic replaced it with a new one, and then replaced that one with another new one just in case the first was defective right out of the box.
 
I'm hazarding a guess here, but I believe you should try and disconnect one of the Dynon HDX screens completely, and just run one screen, and see what you get for Voltage and Amps.

Short of that, ask Dynon what the voltage and current draw is for each HDX unit., and what you have running in the backround.

The HDX, I believe is rated for up to 30V, on a 24V system, so current spikes doing damage is probably highly unlikely. However, the lower the voltage you run, the higher the current or amps you draw. You need at least 22 gauge wire for wiring, per unit. I'd be inclined with the current you are pulling to go use 20 or 18 ga to power the HDX units from the Main circuit, and make sure the wire gauge is heavy enough to cover what's being demanded from the Ducati VR. it's known to only be capable of perhaps 16 amp draw charging rate... Keep in mind, this is a motorcycle voltage regulator, it's not for running Skyview screens, lcds, back lights and cooling fan motors for each unit to keep the computer parts cool.


Can you turn the daytime brightness down on each of the HDX units and see if it draws less current?

Other than that, I am out of ideas. Is the wiring gauge from alternator to voltage regulator to the main buss and to the HDX units an adequate gauge? I know previous posters have stated, at least with the earlier Skyview 1000 Touch that the Rotax alternator couldn't run two panels.

Do you have Auto pilot turned on? Can you de active it or turn it off?

Look at pages 2.2 through 2.5, to calculate your current load. The Auto pilot and servos take a good chunk of juice.

https://dynonavionics.com/public_ht...ystem_Installation_Guide-Rev_AC_v15_2_002.pdf


Worst case, you might have to just settle for only one HDX unit in your bird, or get an additional alternator and Ducati VR to make enough voltage and current to keep up with demand.

Or yank the WiFi adapters?

All of these suggestions are good ones, especially for a newly-built plane that had electrical problems right from the start. However, my plane is a year and half old with 170 Hobbs hours, and it had no electrical problems until a few weeks ago. Also, the negative amp/declining voltage problem came on suddenly. The plane was perfect for a flight from Santa Monica to Torrance (about a half-hour of engine time, including taxi and run-up). The plane was on the ground, in the shade, at Torrance for 3 hours having vinyl tail numbers and an RV-12 vinyl logo applied. I was with the plane the entire time. No one turned it on or fiddled with it in any way. When I started the engine to return to Santa Monica, the engine fired up immediately and without hesitation; but the amps remained negative throughout my taxi and my run-up at 4000 rpm. And that's the way it's been ever since.
 
The missing measurement here - the important one - is: What is the buss voltage with the engine running? If it is not over 14 volts then you have a charging system issue. If it is over 14 (but less than 15) volts then you have a display/measurement problem.
 
The missing measurement here - the important one - is: What is the buss voltage with the engine running? If it is not over 14 volts then you have a charging system issue. If it is over 14 (but less than 15) volts then you have a display/measurement problem.

OK. I'll get the bus voltage. I hate to ask this on a public forum, but where exactly do I measure the "buss voltage"?

Also, if my buss voltage isn't over 14 volts, but my stator is putting out 15 volts AC at idle, and more volts at higher RPMs, and my rectifier/regular is brand new, what could be the problem?
 
I don?t have a Dynon, but I cannot imagine that it doesn't display the input voltage somewhere. That?s the avionics buss voltage. What does it say, engine running? (otherwise, attach the voltmeter to the back of any circuit breaker, other lead to ground, start the engine, turn on buss switches if any, read the voltage.)
 
Your buss voltage should be at or nearly the same as B+ on the voltage regulator and + terminal on the battery, when the engine is running.

You'll need 2700 rpm or more to generate positive amps with just a single HDX running.

I'd be very tempted to pull the Wifi's completely, since after putting those in, that's when the problems started. I'd think Blutooth would pull a lot less current than Wifi's, since they are much shorter range transceivers.

Sounds to me like you just have too much electronics running, pulling too much current.

Keep in mind, you have TWO backup batteries to recharge too, for each HDX, that pull current too.
 
The problem is that the voltage on regulator terminal "C" is supposed to be equal to battery voltage, but it is not. The fuse is likely blown.
 
Also,

Tear everything apart that has a ground... alternator, engine, engine mounts, ground wire mounts, ground for your HDX units, everything, and scuff them all up. It might be on the ground side and not the hot side, that is causing the problems. Including the battery terminal too, and the connector wires at the battery, wire brush them all so they are fresh metal and shiny.

You basically have to trouble shoot every single electrical connection between alternator, voltage regulator and battery, hot side and ground side, assuming you are getting 15.0V plus out of the alternator. Think of a schematic of electrical and how the current flows on both sides, + and ground.
 
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The problem is that the voltage on regulator terminal "C" is supposed to be equal to battery voltage, but it is not. The fuse is likely blown.
Wow! This possibility brightens my day enormously! I'll check the fuses tomorrow, and report back. I'm not superstitious, but I'm going to sleep tonight with my fingers crossed. Thank you.
 
I have an early RV-12 with the Dynon D-180. Van's has made changes to the circuit board a couple of times since then.
Assuming that you have a later version, the fuse is probably located inside of the AV50001 Switch and Fuse Module.
Does the master switch light up? If not, that is a good indication that the 1 amp fuse is blown.
That fuse is probably out of sight inside of the AV50001.
 
I too had a failing voltage regulator, but my mechanic replaced it with a new one, and then replaced that one with another new one just in case the first was defective right out of the box.

That was kinda my point. I verified the buss voltage inflight with an independant meter. (Not the component I'm trying to rule out).
 
Keep in mind, if you blew that fuse, you are still drawing too much current with all your electrical devices, and need to determine why you blew that fuse.
 
I have an early RV-12 with the Dynon D-180. Van's has made changes to the circuit board a couple of times since then.
Assuming that you have a later version, the fuse is probably located inside of the AV50001 Switch and Fuse Module.
Does the master switch light up? If not, that is a good indication that the 1 amp fuse is blown.
That fuse is probably out of sight inside of the AV50001.

My plane has the Skyview HDX -- the most recent version of the Dynon. I don't think it has an AV50001 module, because a digital search of both the Skyview Pilot Guide and Installation Guide failed to find either "AV50001" or "Switch and Fuse Module."

My plane does have a fuse panel right above five switches. There are 12 fuses labeled: Genrtr Main Bus; Start; Trim; Fuel Pump; EFIS; Com; Power Outlet; Nav Strobe; Landing Lights; Auto Pilot; Audio; and GPS ADSB.

So, four questions:

1. Are any of those fuses the fuse that may be bad?

2. Indeed, what does a bad fuse look like? During pre-flight, I've been looking for fuses that turned black or grey, but none have.

3. Is the "Switch and Fuse Module" the box that's behind my fuses and five switches?

4. If so, are you saying that the fuse that may be bad is hidden inside that box?
 
Are you sure your C pin is 1.18 volts or is that a smartphone typo and it's 11.80V? I want you to be double sure about that measurement.
 
My plane has the Skyview HDX -- the most recent version of the Dynon. I don't think it has an AV50001 module, because a digital search of both the Skyview Pilot Guide and Installation Guide failed to find either "AV50001" or "Switch and Fuse Module."

My plane does have a fuse panel right above five switches. There are 12 fuses labeled: Genrtr Main Bus; Start; Trim; Fuel Pump; EFIS; Com; Power Outlet; Nav Strobe; Landing Lights; Auto Pilot; Audio; and GPS ADSB.

So, four questions:

1. Are any of those fuses the fuse that may be bad?

2. Indeed, what does a bad fuse look like? During pre-flight, I've been looking for fuses that turned black or grey, but none have.

3. Is the "Switch and Fuse Module" the box that's behind my fuses and five switches?

4. If so, are you saying that the fuse that may be bad is hidden inside that box?

Most of those fuses, if they go bad, the bad fuse lights up with a LED to indicate the bad fuse.
 
If that 1 amp fuse for regulator terminal "C" proves to be very difficult to
replace, some people have elected to jumper it by connecting regulator
terminals B & C. Doing that is a bad idea because it disables half of the
master switch, the half that shuts off the regulator. If there is smoke in the
cockpit, shutting off the master will not shut off the electrical power because
during cruise, all power is coming from the alternator, not from the battery.
Either replace the blown fuse or do the following:
Install a new inline ATC fuse (available at auto parts store) near the voltage
regulator, connecting one side of the fuse to regulator terminal B or R.
Connect the other side of the fuse to D-Sub pin 13 of the "AV50002 Ignition
and Start Module". The existing white/Yellow 8 inch long wire that connects
to pin 13 can be removed and replaced with the new fuse wire, or the new
fuse wire can tap into the existing wire. Your option.
Making this repair does not modify the original circuit which remains
electrically the same, even though the wires are physically relocated.
 
The C pin voltage was 1.18 volts. That was not a typo.

It turns out that my Dynon does have an AV-50001. It isn't mentioned in the Pilot Guide or Installation Guide. But it does show up in the Builder's Plans.

I can easily get to and remove the AV-50001. Replacing a soldered-in fuse will be trickier though. And before I try to do that, or just buy a new AV-50001, let me ask:

Why would that blown fuse, or a C pin voltage of 1.18, cause my charging system to fail?

I thought that the C pin simply measured the battery voltage and then turned the Rectifier off if the battery's voltage was at max or turned the Rectifier on if the battery voltage was low. I understand why this is very important. But if the Regulator thinks my battery voltage is just 1.18, wouldn't it turn the Rectifier on, rather than off, and if the Rectifier is on, wouldn't it charge the battery?
 
The C pin voltage was 1.18 volts. That was not a typo.

It turns out that my Dynon does have an AV-50001. It isn't mentioned in the Pilot Guide or Installation Guide. But it does show up in the Builder's Plans.

I can easily get to and remove the AV-50001. Replacing a soldered-in fuse will be trickier though. And before I try to do that, or just buy a new AV-50001, let me ask:

Why would that blown fuse, or a C pin voltage of 1.18, cause my charging system to fail?

I thought that the C pin simply measured the battery voltage and then turned the Rectifier off if the battery's voltage was at max or turned the Rectifier on if the battery voltage was low. I understand why this is very important. But if the Regulator thinks my battery voltage is just 1.18, wouldn't it turn the Rectifier on, rather than off, and if the Rectifier is on, wouldn't it charge the battery?
A charge controller with rectifiers also has a "low side voltage" limit, to prevent damage to the alternator, in the event the battery has a shorted cell. It also should prevent the battery from bulging or exploding, if a cell indeed has shorted out on the battery.
 
The AV50001 and AV50002 are not Dynon products. They are Van's.
1. NO
2. Bad fuses may be hard to spot, especially a 1 amp fuse. Best to check with a meter.
3. Yes, most likely. My plane is different, so I can not be 100 percent sure.
4. Yes.
Remember to check to see if the master switch lights up like the other switches do.
 
Regulator pin C must have battery voltage on it before the regulator will turn on.
Do not buy a new AV-50001 or pay to have it fixed. Install an inline fuse as
described above. Like I said, the circuit will still be electrically identical, even
if physically different. If the fuse blows again, it can then be easily replaced.
Sometime fuses blow for no apparent reason. They are a weak link in a
circuit. Suppose there is an intermittent short circuit that caused the fuse to
blow. Why pay for an expensive repair or replacement, only to have the fuse blow again?
 
Why would that blown fuse, or a C pin voltage of 1.18, cause my charging system to fail?

The C pin is both control and sense. The power on the C pin is what drives the SCR Gates, no C pin power, no gate voltage, no output. The sense circuit turns off the the gates when the set point is reached typically 14volts.
 
I have an early RV-12 with the Dynon D-180. Van's has made changes to the circuit board a couple of times since then.
Assuming that you have a later version, the fuse is probably located inside of the AV50001 Switch and Fuse Module.
Does the master switch light up? If not, that is a good indication that the 1 amp fuse is blown.
That fuse is probably out of sight inside of the AV50001.

I just got back from the airport. The Master switch does not light up when the Master is turned on. But the Ignition A and B switches do light up, and they are right next to the Master and in the same AV-50002 Ignition & Start module.

Would the Ignition A and B switches continue to light up, even if the fuse in the Switch and Fuse Module has blown? I ask, because I'm wondering whether the Master switch doesn't light up simply because the switch light itself has gone out, rather than because of a blown fuse. I'm hoping that the answer is that the Ignition A and B switch lights have nothing to do with the fuse and would continue to light up even if the fuse is blown. I hope that, because then you'll have helped me get a giant step closer to repairing the problem that's kept my plane on the ground for more than three weeks . . . of beautiful flying weather!
 
The C pin is both control and sense. The power on the C pin is what drives the SCR Gates, no C pin power, no gate voltage, no output. The sense circuit turns off the the gates when the set point is reached typically 14volts.

Thanks for this. I'm trying to understand what's going on, as well as fix it. And this explains a lot.
 
The fact that master switch light is not working confirms that the 1 amp fuse
is blown. Ignition A and B switches should continue to light up because
they do not get power from the blown fuse. The master switch light is an
LED, which is unlikely to fail.
The best long term solution is to install an inline fuse holder near the
voltage regulator. If the new fuse blows in the future, it will be easy to
replace. The hardest part of the repair will be removing and reinstalling the
instrument panel sheet metal cover. You can have the plane back in the air
by lunch time tomorrow. The new fuse should be wired between regulator
terminal B and D-Sub pin 13 of the "AV50002 Ignition and Start Module".
 
The fact that master switch light is not working confirms that the 1 amp fuse
is blown. Ignition A and B switches should continue to light up because
they do not get power from the blown fuse. The master switch light is an
LED, which is unlikely to fail.
The best long term solution is to install an inline fuse holder near the
voltage regulator. If the new fuse blows in the future, it will be easy to
replace. The hardest part of the repair will be removing and reinstalling the
instrument panel sheet metal cover. You can have the plane back in the air
by lunch time tomorrow. The new fuse should be wired between regulator
terminal B and D-Sub pin 13 of the "AV50002 Ignition and Start Module".
This is the best news I've gotten in more than three weeks. Thank you!
 
I am a member of blew the 1 amp fuse that powers the VR club. I did it last year right before Oshkosh when I was installing ADS-B in and out, auto-pilot control module, knob module, and a Tosten stick grip. When I test flew the airplane the day before I was leaving for Oshkosh, I realized the battery was not charging. So last year I had to drive to Oshkosh.

I just studied the wiring diagram and I really like Joe's solution. My solution came from Van's and was to jumper the B & C terminals on the VR. I have read all the negative comments about that solution. I would like to get the green light on the Master Switch working again.

My question is "Has anyone replaced that one amp fuse" and if so, how hard is it. Al I know is it is soldered on the circuit board and Van's said to send it back for repair. I want to replace it myself, and I have a good bit of experience soldering, but I don't want to create a bigger problem. So has anyone done it and can you tell me about your experience.

Thanks
 
My solution as described above restores the circuit to its original condition,
electrically speaking, even though it looks completely different. Basically the
fuse is being relocated to an easily accessible location near the voltage
regulator. Looking at Van's schematic, one end of the blown fuse is
connected to regulator terminal B. Follow the other end of the blown fuse
through the maze and it connects to D-Sub pin 13 of the AV-50002 Ignition &
Start Module. Those are exactly the same locations where the new inline
fuse will be connected. The only difference is that the new fuse is easily
accessible for replacement if necessary. After installing the new inline fuse,
the light on the master switch will work again.
So remove that jumper that creates a potential hazard. And install an
inline fuse so that the circuit will work as originally designed.
 
Lon,
Is your charging system working?

Yes! As of 11 o'clock this morning. All thanks to you. Your diagnosis of a blown fuse in the Van's Switch & Fuse Module (AV-50001) was spot on.

Your recommended treatment -- inserting a new fuse between regulator terminal B and D-Sub pin 13 of the Ignition and Start Module -- is ingenious, and I considered it long and hard. Ultimately, though, I bought and installed a new Switch & Fuse Module, for reasons that were specific to my own circumstances.

Your recommendation would have cost just a sliver of what I paid to have Van's send me a new Module ($12 vs $370 plus tax and shipping). And your solution would have made replacing the new fuse cheap, simple and fast. I went with a new Module instead, because: I don't own the tools needed to follow your recommendation; I don't have a hangar to work in; and I didn't build the plane and had no experience maintaining it. It looked to me as though your recommendation would be a real project, while swapping out the old Module and putting in a new one would be easy. (Getting the old one out and putting in the new one turned out to be more difficult than I though it would be, but I did it.)

But the most important reason I decided to replace the Module is that my plane is an ELSA. Right now ELSAs cannot legally be used for flight instruction, but there is a pending FAA rule-making proceeding that is likely to result in a rule that permits ELSAs to be used for training. And I didn't want to do anything that might disqualify my plane, if such a rule is adopted.

Again, thank you so much for responding to my original post with your 100% accurate diagnosis. You are a life-saver, or at least a psyche-saver. For several days before your post, I feared that I was the owner of $90,000 worth of used airplane parts that I had no way of moving. Now I am once again the owner of a terrific little airplane that flies!
 
Another option for anyone finding them self with a blown soldered in fuse is to return it to Van's to have the fuse replaced.
The cost of the repair is far less than the purchase price of the entire module.
 
Another option for anyone finding them self with a blown soldered in fuse is to return it to Van's to have the fuse replaced.
The cost of the repair is far less than the purchase price of the entire module.

Now you tell me! [;-)

I thought that return-for-repair might be a possibility. But I'd been unable to fly my plane for more than 3 weeks, and when learned how to fix it, I was in a hurry to do that. I ordered a new module last Monday (a holiday, but Van's was working anyway), and the module was delivered on Wednesday. It was fast.

Also, my plane is at KSMO (Santa Monica), and frankly, between the airport's fees and insurance requirements, my per-day fixed ownership costs (not including fuel or maintenance) are so great that I haven't yet dared to calculate them. So not having the plane available is itself a cost, psychologically.

But, since you offered, how much would it cost to get my old module repaired? I may send it in for repair, so I'll have a spare in case the fuse in the new one blows as well, especially because I have no idea why the old one blew.
 
Now you tell me! [;-)

I thought that return-for-repair might be a possibility. But I'd been unable to fly my plane for more than 3 weeks, and when learned how to fix it, I was in a hurry to do that. I ordered a new module last Monday (a holiday, but Van's was working anyway), and the module was delivered on Wednesday. It was fast.

Also, my plane is at KSMO (Santa Monica), and frankly, between the airport's fees and insurance requirements, my per-day fixed ownership costs (not including fuel or maintenance) are so great that I haven't yet dared to calculate them. So not having the plane available is itself a cost, psychologically.

But, since you offered, how much would it cost to get my old module repaired? I may send it in for repair, so I'll have a spare in case the fuse in the new one blows as well, especially because I have no idea why the old one blew.

Your per diem costs will exceed the costs of the part when you include shipping costs both ways and turn around times. Trust me on this. Patch wire in a fuse holder at the VR to the switch, behind the dash. Make sure the gauge of wire used will flow enough current. 30 amps is 10 ga, 20 amp is 12 ga, 15 amps is 14 ga. If you are still blowing fuses, you better find out why and what is drawing all the current causing the blown fuses.

It's my understanding that there was a 1 amp fuse built into that switch. That's probably what you should replace with and 20 to 22 ga wire should be more than sufficient for 1 amp.
 
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If you are

Your per diem costs will exceed the costs of the part when you include shipping costs both ways and turn around times. Trust me on this. Patch wire in a fuse holder at the VR to the switch, behind the dash. Make sure the gauge of wire used will flow enough current. 30 amps is 10 ga, 20 amp is 12 ga, 15 amps is 14 ga. If you are still blowing fuses, you better find out why and what is drawing all the current causing the blown fuses.

You've just touched on one of the reasons I decided to buy a new module instead of the fuse patch that you and Joe recommend. I've never built a plane. This is the first plane I've ever owned, and I've owned it for just four months. I rented for 7 years. All of the flight schools from which I rented took care of everything, including putting fuel in the planes. Indeed, one school from which I rented prohibited renters from putting fuel in its planes, insisting instead that its planes be fueled by airport employees. In other words, until this week, I was a virgin when it came to airplane maintenance and repairs. You make a good point about using the right gauge of wire for the fuse patch. But I didn't know what the right gauge would be.

I agree that I need to find out why the fuse blew. But I don't know how to find out why. Joe says that fuses sometimes blow for no apparent reason. My plane is an ELSA which means it's a duplicate of a factory-built RV-12. It doesn't have anything electrical that factory-builts don't have. And my plane flew perfectly for more than a year and a half, 170 Hobbs hours, before the fuse blew. I don't think the plane is overloaded with electronics, but I'll keep a close eye on the Amps from now on.
 
You've just touched on one of the reasons I decided to buy a new module instead of the fuse patch that you and Joe recommend. I've never built a plane. This is the first plane I've ever owned, and I've owned it for just four months. I rented for 7 years. All of the flight schools from which I rented took care of everything, including putting fuel in the planes. Indeed, one school from which I rented prohibited renters from putting fuel in its planes, insisting instead that its planes be fueled by airport employees. In other words, until this week, I was a virgin when it came to airplane maintenance and repairs. You make a good point about using the right gauge of wire for the fuse patch. But I didn't know what the right gauge would be.

I agree that I need to find out why the fuse blew. But I don't know how to find out why. Joe says that fuses sometimes blow for no apparent reason. My plane is an ELSA which means it's a duplicate of a factory-built RV-12. It doesn't have anything electrical that factory-builts don't have. And my plane flew perfectly for more than a year and a half, 170 Hobbs hours, before the fuse blew. I don't think the plane is overloaded with electronics, but I'll keep a close eye on the Amps from now on.

Hopefully, you don't blow another internal fuse module. Something tells me you are drawing too much current and that's why the fuse blew. Or you had a low voltage situation from a low battery state of charge, upping the current draw.
 
The blown fuse that caused the non charging issue being discussed is a pcb mounted / soldered in one amp fuse that supplies a sense voltage to the voltage regulator. It is not inside of any switch.

I am a bit baffled why someone would make an estimate of what a repair cost would be when as far as I am aware they have never submitted an AV-50001 switch module for repair.


I have no responsibility for invoicing repairs so I can't say exactly what the billed amount is but I think it is the neighborhood of $70. Add shipping to and from Van's to that and it would still be way south of $370.

I agree it would not have been as fast of a repair because of the shipping time in two directions instead of one, plus the turn around for the repair (usually 2-3 business days)
 
The blown fuse that caused the non charging issue being discussed is a pcb mounted / soldered in one amp fuse that supplies a sense voltage to the voltage regulator. It is not inside of any switch.

I am a bit baffled why someone would make an estimate of what a repair cost would be when as far as I am aware they have never submitted an AV-50001 switch module for repair.


I have no responsibility for invoicing repairs so I can't say exactly what the billed amount is but I think it is the neighborhood of $70. Add shipping to and from Van's to that and it would still be way south of $370.

I agree it would not have been as fast of a repair because of the shipping time in two directions instead of one, plus the turn around for the repair (usually 2-3 business days)

Only Lon knows what his fixed expenses per day are, and what his professional time is still worth. My educated guess is that he is or was able to bill in the mid to high multiple $100's per hour for his time. The new replacement part was evidently worth it to him, vs the down time.

I can't imagine Santa Monica Airport in Los Angeles being cheap per month, let along per day, when your plane is non op, to keep your plane at, not when Harrison Ford kept his plane there. The real estate all around that airport, in the event of an accident, can't make insurance rates cheap, either if a take off or landing creates liability damage to that below you. You don't always get the luxury of landing on the golf course, in the event of engine failure. Very, very high density housing down there, on expensive land, in Santa Monica, CA.

https://www.usatoday.com/story/life...rts-cause-harrison-ford-plane-crash/31246511/
 
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Does this web site have a method of ignoring individual posters so I do not have to see someones posts that are normally hypothetical or without merit? You know, someone that does not even have an RV 12 and knows everything about them. If so, please let me know. There is someone I would love to exclude from my morning peruse and save my valuable time.

Keep scrolling... there's a lot of A/P's out there too that don't own a RV-12 and work on them.
 
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The fact that master switch light is not working confirms that the 1 amp fuse
is blown. Ignition A and B switches should continue to light up because
they do not get power from the blown fuse. The master switch light is an
LED, which is unlikely to fail.
The best long term solution is to install an inline fuse holder near the
voltage regulator. If the new fuse blows in the future, it will be easy to
replace. The hardest part of the repair will be removing and reinstalling the
instrument panel sheet metal cover. You can have the plane back in the air
by lunch time tomorrow. The new fuse should be wired between regulator
terminal B and D-Sub pin 13 of the "AV50002 Ignition and Start Module".

To follow-up on Joe's inline fuse solution, D-Sub pin 13 is on the white/yellow wire of the short 8" IGNITION harness attached to the AV50002 Ignition and Start Module. I think it might be easy to access the short 8" IGNITION harness by removing the D1000/HDX and working through the opening and without having to remove the avionics bay cover. If necessary, removing the cover would, of course, allow easy access as can be seen in the picture.

i-53j9Gcw.png

i-BZnCRz4-L.jpg


If the short harness is removed the new fuse wire could be attached while working at a work bench. After replacing the harness the new wire could be routed through an existing snap bushing to the VR location.
 
Tony,

Thanks for this. Two questions:

1. Is D-Sub pin 13 now an open unused pin, or would the new fuse wire share that pin with another wire that's already attached?

2. In your photo, it looks as though the Ignition Harness is routed through a black tube, just below the red shrink wrap, and that the black tube is much narrower than the D-Sub. If so, how would I get the Harness out of the plane and then back in again. Or is the "tube" actually part of the D-Sub itself, so that once I get access to it, I'll be able to take it out without passing it through anything?
 
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