VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Model Specific > RV-12
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 06-20-2017, 11:38 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,449
Default

The Rotax dynamo will keep on working even if the battery is disconnected. However without the battery, the voltage will not be stable and vary up and down about 3/4 of a volt from its setpoint. That causes the Dynon to give a voltage alarm. The voltage regulator does not think that the voltage is low because it monitors electrical system voltage, not battery voltage. The regulator does not call for full output. The electrical system voltage is still around 14 volts, plus or minus one volt. All electrical loads are still powered by the dynamo like they always are, whether the battery is connected or not. The trim worked because it was powered by the dynamo.
__________________
Joe Gores
Reply With Quote
  #22  
Old 06-20-2017, 03:57 PM
Piper J3's Avatar
Piper J3 Piper J3 is online now
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 621
Default

Update: I’m still verifying wiring while waiting for the new Master Relay from Van’s. I was convinced that the AV Control Board 12 (fuse/switch assembly) was unharmed even with electrical smell (see post #1). Well I guess it was fake news or alternative facts, because the master switch isn’t working.

I removed the sheet metal protective backing on the circuit board and can now see where the foil tracings have lifted from heat. This is not an easy fix because the tracings are inaccessible as two circuit boards face each other and cannot be separated.

The solution is to replace the entire assembly. I’ve called Van’s and they stock the part but the cost is prohibitive. I’m wondering if someone might have one of these assemblies lying around. Perhaps someone built their own panel or installed a different engine and didn’t use the AV Control Board 12 that was furnished with the kit.

Let me know if you have an AV Control Board 12 and we can work a deal. I’ll also post an ad in the VAF Classified Thread.

Thanks for listening…

Direct email is strickjc@frontier.com
-
__________________
-
Jim Stricker
Hinckley, Ohio
PPL - 1970
80 hrs Flying Aeronca Chief 11AC
1130 hrs Flying 46 Piper J-3 Cub
RV-12 E-LSA #120058 AWC 7/12 Bought Flying 10/2015 with 48TT - Hobbs now 261
Reply With Quote
  #23  
Old 06-20-2017, 08:03 PM
MMiller MMiller is offline
 
Join Date: Oct 2010
Location: Babylon NY
Posts: 59
Default

Jim, you may want to stop and pause. You need to find out what's going on. If you have a melted trace on the PCB…this is a secondary failure, not the primary failure. Something caused this trace to exceed its design current. Installing a new control module will likely cause the same trace to delaminate again.

You said this trace is in the master relay circuit. This is an unfused circuit with the coil connected directly to the battery. The two most likely failure modes in this case are a shorted coil (it should measure 17.5 ohms) or a shorted (or backwards) coil discharge diode.

If the trace is not melted open, and you have an open circuit, you may have damage to the P44 white/orange wire between the module and master relay.

We need to address the cause of the problem, not the symptoms.

Mike
Reply With Quote
  #24  
Old 06-20-2017, 08:53 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 1,981
Default

I'd tentatively agree with Mike, pending more info about what's actually on those circuit boards. You do need to determine what overloaded that trace.

Does Van supply a *complete* schematic for the a/c, including all the interconnections on that module? If so, it can possibly be repaired. Separating the two boards, & repairing the burned trace, shouldn't be too hard for an electronics tech.

If you have good docs & you want to give repair a shot, send me an email with some more pics. Try to show the burned trace & how the boards are married to each other.

Charlie
mcsophie@gmail.com
(electronics tech in a couple of former lives)
Reply With Quote
  #25  
Old 06-22-2017, 03:48 AM
Piper J3's Avatar
Piper J3 Piper J3 is online now
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 621
Default

I installed the new Master Relay with my new wire that controls it which I soldered to the back of the master switch. Success. Master Relay pulls in and reference voltage shows up at the voltage regulator.

Engine runs and voltage regulator works so main problem is solved. Both ignitions working. Avionics and EFIS are working.

All functions working accept the following:

• Master switch LED indicator does not work
• No LED’s working on any of the panel switches (avionics, landing lights, etc)
• Trim motor not working - fuse OK
• Stall warning not working - fuse OK
• Audible warnings in headset not working

My question - is there something in common for all these items to not have power? Does the master switch also power these items and the fact that it’s own LED doesn’t light mean its not passing power to these other items? When I had power surge from the defective Master Relay could it have damaged the master switch in a way I can’t detect with an ohmmeter? My suspicion is the master switch has an internal fault. I’m also thinking maybe sensitive electronic components got damaged.

Beginning to look like I need to replace the entire Control Board. Anybody have a Control Board left over from maybe a panel upgrade or engine conversion requiring different controls?

Again, any help appreciated…
-
__________________
-
Jim Stricker
Hinckley, Ohio
PPL - 1970
80 hrs Flying Aeronca Chief 11AC
1130 hrs Flying 46 Piper J-3 Cub
RV-12 E-LSA #120058 AWC 7/12 Bought Flying 10/2015 with 48TT - Hobbs now 261

Last edited by Piper J3 : 06-22-2017 at 04:01 AM.
Reply With Quote
  #26  
Old 06-22-2017, 04:29 AM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,433
Default

Jim, so sorry for your problems. It is beginning to look like the surge cooked several of the more sensitive electronic components, such as the dimmer circuitry, trim servo, audio circuits etc. some of the electronic gurus can weigh in on this, but that's the way it seems to me. Even if you were able to replace/repair individual components, I think tou need to ask yourself if you want to fly behind a module that has been subjected to this kind of abuse.
__________________
John Peck, CFII, A&P, EAA Tech Counselor, Flight Advisor.
RV-12 N37JP 120176 Flying since 2012.
VAF paid through 10/2017. Best bargain in town.
Reply With Quote
  #27  
Old 06-22-2017, 04:50 AM
MMiller MMiller is offline
 
Join Date: Oct 2010
Location: Babylon NY
Posts: 59
Default

Jim, here is a link to a schematic for the D180, for troubleshooting it's much easier to follow than Van’s drawing;

https://drive.google.com/open?id=0By...y01dEstc09QMVk

The only thing common to all those, except the dimmer, is a ground for the electronics on the PCB. I'm not sure where that comes into the board. As I recall the module had its own ground wire with a ring terminal to a screw, on back…but it was a long time ago, so I'm not sure how this tied together.

The dimmer is driven from a PMW output from the D180, it needs to be on.

Is there any chance you had your battery wired backwards during your troubleshooting…this would also explain the melted trace in the master circuit and the smell of overstressed silicone.

Even if your VAN's board is damaged all the components in these circuits cost about $15....including freight.

Mike
Reply With Quote
  #28  
Old 06-22-2017, 04:29 PM
Tommycat's Avatar
Tommycat Tommycat is offline
 
Join Date: Feb 2017
Location: North-western Illinois
Posts: 64
Default

Mike,
Thank you for that excellent schematic!

Quote:
Originally Posted by Piper J3 View Post

I installed the new Master Relay with my new wire that controls it which I soldered to the back of the master switch.

It may be helpful if you where to draw on the schematic where the trace was burnt, and where you installed the repair wiring.


My question - is there something in common for all these items to not have power?

I would suspect it's not about having power...but having a good ground.


Does the master switch also power these items and the fact that it’s own LED doesn’t light mean its not passing power to these other items?

The master switch itself only supplies power to terminal 1 when ON, which is connected to the voltage regulator C terminal for voltage sensing and the LED anode for operation indication.


When I had power surge from the defective Master Relay could it have damaged the master switch in a way I can’t detect with an ohmmeter?

Possible...but unlikely. You could also try a light probe tester. But remember always isolate the components when troubleshooting. And that this switch internally has 2 different switches, that control 2 different circuits.


My suspicion is the master switch has an internal fault.

It pulls in the master relay, and the regulator is working properly...it's two jobs in life. If the LED is rated at 12 vdc, grounding terminal seven, with switch on should light the light. Verify rating and isolate before trying...

I'm sticking with damaged or missing ground.


I’m also thinking maybe sensitive electronic components got damaged.

Innocent until proven guilty.
Lots of wires and pins here... I would recommend re-seating every connector paying particular attention to P2, a PCB interconnect and double checking grounding wires,pins, and connections.
If needed I would pick out the easiest circuit not working to troubleshoot, and go from there.

Best regards,
__________________
T.C.

VAF Supporter

Last edited by Tommycat : 06-23-2017 at 06:23 AM. Reason: Not sure of LED rating...
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 04:55 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.