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Avionics circuit

C

csmith3603

Well Known Member
My problem is when I turn on the Avionics switch the Radio (GTR200B) comes ON and Squeals thru the headphones!
So,,, the circuit with the squealing's is coming from the Avionics switch wiring! The Radio (GTR200R) was bench tested
for 120.00 and was Ok.

The NavCom breaker fuse did blow and was replaced.

I was told by support to test very fuse except Com Fuse to see if the sequel goes away.

The only thing not checked yet is every fuse in the Rotax 912iS Fuse Box! There is NO documentation for this Rotax 912iS fuse box!

Could it be A AV-60000 issue?
 
I don’t know it will help you, but the fuses in the Rotax fuse box are documented in the Heavy Maintenance Manual.
 

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Have you tried checking if the insulation washer is installed properly on both sets of jacks for your headphones and mic? I got a squeal that would come and go very loud and annoying from a GTR 200 and I tracked it down to a lose jack nut that allowed the insulator to be lose and the jack to touch the panel.
 
I would try and isolate the radio from everything else. Perhaps find a way to provide power only to the radio. Possibly you can do this by pulling the fuse and then jumpering 12v directly to the radio only. That will tell you if its something to do with the installation, or if something else in the aircraft is generating the noise.
 
csmith3603 said:
So,,, the circuit with the squealing's is coming from the Avionics switch wiring! The Radio (GTR200R) was bench tested
for 120.00 and was okay….
Click to expand...
This is a poor assumption. Squealing is generally caused by ‘feedback’, that is, somehow the output audio is being ‘fed back’ into the mike input (or elsewhere internal to the radio).
As another poster suggested, look carefully under the panel at the headphone jack, with both mike and phone plugs plugged in. Is anything from one jack touching the other? Try unplugging the mike plug. If squealing goes away the issue is jacks touching or short in the headset or headset wiring. Always try easy stuff first.
 
i think i had this once.. and it was my copilot's headset volume that was jacked allllll the way up.. feeding back into its own microphone. eventually the GMA245 cuts off the audio because it thinks its just background noise..
 
Bob Y said:
I don’t know it will help you, but the fuses in the Rotax fuse box are documented in the Heavy Maintenance Manual.
Click to expand...
I have checked the washers under the phone jacks. unpluged the DB9 wire to the AV60000 and sticks and swapped
Dynon HDX and still squeals. Its got to be the AV-6000 for 575.00 and no warranty!.....
 
I very much doubt issue is with power going to the radio... Bench testing is completely different than testing in an aircraft - I suspect an aircraft wiring issue. NO mic should be picking up anything until the PTT is pressed unless these is an intercom function. Do you have a wiring diagram of the installation including the other avionics and the new radio... that would help greatly in troubleshooting (audio panel, Com's, Intercom if separate, mic jacks, phone jacks etc.
 
AZSteve053 said:
I very much doubt issue is with power going to the radio... Bench testing is completely different than testing in an aircraft - I suspect an aircraft wiring issue. NO mic should be picking up anything until the PTT is pressed unless these is an intercom function. Do you have a wiring diagram of the installation including the other avionics and the new radio... that would help greatly in troubleshooting (audio panel, Com's, Intercom if separate, mic jacks, phone jacks etc.
Click to expand...
The Headphone squeal stops when I pull the Avionics Fuse (Smile). No trim,,So pull the WP-P30-1 going to AV-60000. still squeals. Van's support says there are options? Yep the AV-60000 at about 600.00 guess!
 
Majorpayne317641 said:
Have you tried checking if the insulation washer is installed properly on both sets of jacks for your headphones and mic? I got a squeal that would come and go very loud and annoying from a GTR 200 and I tracked it down to a lose jack nut that allowed the insulator to be lose and the jack to touch the panel.
Click to expand...
Yes, that was the first thing I did. pull the avions fuse and the sequel went away.
 
BobTurner said:
This is a poor assumption. Squealing is generally caused by ‘feedback’, that is, somehow the output audio is being ‘fed back’ into the mike input (or elsewhere internal to the radio).
As another poster suggested, look carefully under the panel at the headphone jack, with both mike and phone plugs plugged in. Is anything from one jack touching the other? Try unplugging the mike plug. If squealing goes away the issue is jacks touching or short in the headset or headset wiring. Always try easy stuff first.
Click to expand...
Checking the headphones and wiring configuration was done first. The clue is that the squeal goes away after you unplug the trim fuse!
 
Bob Y said:
I don’t know it will help you, but the fuses in the Rotax fuse box are documented in the Heavy Maintenance Manual.
Click to expand...
Thanks. I looked for this! Thanks. I checked the fuses also! The squel stops when you pull the TRIM START fuse. There is an area in the AV-6000 that process this. Bad AV-60000?
 
walkman said:
I would try and isolate the radio from everything else. Perhaps find a way to provide power only to the radio. Possibly you can do this by pulling the fuse and then jumpering 12v directly to the radio only. That will tell you if its something to do with the installation, or if something else in the aircraft is generating the noise.
Click to expand...
Howdy there. Pulled the Trim Start fuse and the squeals stops! The radio now works! Toothless smile. There is an area in the AV-6000 (IC) that process the Trim Start circuit. (Bad?) The RV-12 wiring harness ($) is like nothing compared to other Van's Aircraft. They designed there own proprietary master bus and hardware! I used a composite design master bus with another RV-12 Build, Its simple!
 
The pitch trim likely has a PWM circuit which controls the speed of the trim motor.
The PWM circuit might be operating at the wrong frequency. If it is not desired to repair the PWM circuit, it could be replaced by a resistor sized to reduce the trim voltage from 14 down to 10 or 11 volts. The disadvantage of doing that is that the trim would be very sensitive. Short presses of the trim button could result in large trim changes.
Of course this is all speculation.
 
Mich48041 said:
The pitch trim likely has a PWM circuit which controls the speed of the trim motor.
The PWM circuit might be operating at the wrong frequency. If it is not desired to repair the PWM circuit, it could be replaced by a resistor sized to reduce the trim voltage from 14 down to 10 or 11 volts. The disadvantage of doing that is that the trim would be very sensitive. Short presses of the trim button could result in large trim changes.
Of course this is all speculation.
Click to expand...
Howdy there; This is an RV-12iS electrical issue. The RV-12 models have a engineered Wiring Harness and propertary master bus system. When I pull the TRIM START fuse the squeal stops! Ok. In reading the wiring schematic, Power Module AV-6000 has an area IC called TRIM START. There is one for NAV COM too and the fuse was blown! This part is not documented for its errors yet by support....? 600.00
 
Are you sure the "squeal" isn't the stall warning audio tone? Is the "STALL" warning displayed on the EFIS screen?

Pulling the TRIM START fuse kills the power to the Arduino where the stall warning tone is generated.
 
Tony Kirk said:
Are you sure the "squeal" isn't the stall warning audio tone? Is the "STALL" warning displayed on the EFIS screen?

Pulling the TRIM START fuse kills the power to the Arduino where the stall warning tone is generated.
Click to expand...
Howdy there Tony. Yes the "STALL" warning displayed on the EFIS Screen!
 
Hey, if you are going to replace the AV-6000, and you are going to put the old one in a box somewhere, can I have it. I will pay shipping. I am retired, and looking for projects, and maybe I can come up with a fix to the squeal problem, that can be passed on.

Let me know by emailing me at [email protected].

Thanks.

Brian
 
Pdtofly said:
Hey, if you are going to replace the AV-6000, and you are going to put the old one in a box somewhere, can I have it. I will pay shipping. I am retired, and looking for projects, and maybe I can come up with a fix to the squeal problem, that can be passed on.

Let me know by emailing me at [email protected].

Thanks.

Brian
Click to expand...
Spot on to you learning stuff. It appears the direction of fault is coming from the stall warning issues. Yep that box is interesting.
 
csmith3603 said:
Wow. I was wondering about the "STALL" being on,,, so I switched to another Dynon HDX display and the squeal was still there! Wow
Click to expand...
Check that the stall warning vane switch is not stuck in the state to cause the controller to think there is a stall. Also check the wire if the switch is good.
 
Brantel said:
Check that the stall warning vane switch is not stuck in the state to cause the controller to think there is a stall. Also check the wire if the switch is good.
Click to expand...
Yes Sir! Smile. I checked that but now need to pull the cover an check the mico switch. Grin.
 
Tony Kirk said:
Great - since I don't work for Van's anymore you can pay the support fee directly to me, LOL. ;)
Click to expand...
Wow. I can believe how Van's builders love electrical problems. I had this same problem years ago!. I think it was you that solved it before you retired.. Grin. Yep you deserve the support fee! I let Van's support know about you pointing out the "STALL" on the display and the wiring problem with the micro switch at the stall indicator. Thanks again Tony! Smile.
 
Check if wire 216 is grounded. That would tell you if there’s a short to ground somewhere.
 

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csmith3603 said:
Good Morning Tony. Replaced the Connector and Micro switch. Squealing continues. will check wing wiring to plug?
Click to expand...
Make sure you have the wires connected to the proper terminals on the micro-switch. The stall wire connects to the COM and the ground wire connects to the NO (Normally Open) terminal. Also be sure the switch is adjusted properly and not depressed.

Stall Switch.png

I like to cut the unused terminal (NC in this case) off of these switches during installation to avoid inadvertently connecting to the wrong terminal, particularly someplace like the stall switch where you are almost working blind. The spar pin switches also come to mind for unused terminal removal.
 
Tony Kirk said:
Make sure you have the wires connected to the proper terminals on the micro-switch. The stall wire connects to the COM and the ground wire connects to the NO (Normally Open) terminal. Also be sure the switch is adjusted properly and not depressed.

View attachment 86508

I like to cut the unused terminal (NC in this case) off of these switches during installation to avoid inadvertently connecting to the wrong terminal, particularly someplace like the stall switch where you are almost working blind. The spar pin switches also come to mind for unused terminal removal.
Click to expand...
 
Tony Kirk said:
Make sure you have the wires connected to the proper terminals on the micro-switch. The stall wire connects to the COM and the ground wire connects to the NO (Normally Open) terminal. Also be sure the switch is adjusted properly and not depressed.

View attachment 86508

I like to cut the unused terminal (NC in this case) off of these switches during installation to avoid inadvertently connecting to the wrong terminal, particularly someplace like the stall switch where you are almost working blind. The spar pin switches also come to mind for unused terminal removal.
Click to expand...
I will go over these connections again. But all look good. I will check W216 to see if grounded.
 
csmith3603 said:
Thanks. I looked for this! Thanks. I checked the fuses also! The squel stops when you pull the TRIM START fuse. There is an area in the AV-6000 that process this. Bad AV-60000?
Click to expand...
Is the wiring to the trim servo shielded and grounded?
 
Hello there.

Well, I've checked about everything I can!
Van's support has not responded to any of my pleas for help! Two weeks now. I call support and get nothing....
I can fly the airplane by pulling the trim tab fuse! squealing goes away....
The CFI that I fly with says he smells melting plastic!
The only thing left to try is replacing the AV-60000.
 
Howdy there; My name is Charles Smith. I purchased a WH-00133-1 for my Van's Aircraft RV-12iS from you some time ago! I have some Issues with this wiring harness trouble shooting.
Howdy there, I have been having a squeling sound coming out of my earphones as I started my RV12-iS Checklist before flight. Almost 200 hours on this Aircraft ….
Checked fuses and found Nav/Com blown. Replaced
Stall indicator on Dynon HDX display in (RED).
----------------------------------------------------------
Remove Trim Tab Fuse and squealing stops!
Reinstall Trim Tab Fuse.
Tested Trim Tab Motor, display indicator and motor movements are OK.
---------------------------------------------------------
Disconnect Ground on Stall warning micro switch in wing and squealing stops!
Checked Wing Connect ground at wing plug W217 & W216and is Good!
Reconnect Ground on Stall Warning Micro switch and check bus registers for line
C37 P11 Stall Contact: Raw 437 CAL(V) 0.5334 VAL 00.5334
Have continuity on Stall warning line configuration.

I Have had intermittent display indication on display and non function flaps when using the flap switch. Checked wiring, all connections are ok. Smile

My CFI has said that he smells plastic and he is also a lieutenant with the Fire Department.
I have gone thru WH-00133-1and see that all goes thru to AV-60000 Power module.
No body at support has identified this problem or solution as of yet.
Any Suggestions? Replace AV-60000
 
csmith3603 said:
---------------------------------------------------------
Disconnect Ground on Stall warning micro switch in wing and squealing stops!
Click to expand...
If you disconnect the ground wire before the switch and tone turns off, you have one of thee possible problems

1) the switch is misaligned and stuck on
2) the switch is broken and stuck in on position
3) the switch is wired normally closed, not normally open
 
MMiller said:
If you disconnect the ground wire before the switch and tone turns off, you have one of thee possible problems

1) the switch is misaligned and stuck on
2) the switch is broken and stuck in on position
3) the switch is wired normally closed, not normally open
Click to expand...
I replaced the micro switch even when it tested ok. Replaced connectors.
The Switch is normally open! The wind hits it at the right angle and it is closed....Stall light come on.
The airplane is on the ground with the reporting conditions. Thanks
 
Tony Kirk said:
Make sure you have the wires connected to the proper terminals on the micro-switch. The stall wire connects to the COM and the ground wire connects to the NO (Normally Open) terminal. Also be sure the switch is adjusted properly and not depressed.

View attachment 86508

I like to cut the unused terminal (NC in this case) off of these switches during installation to avoid inadvertently connecting to the wrong terminal, particularly someplace like the stall switch where you are almost working blind. The spar pin switches also come to mind for unused terminal removal.
Click to expand...
I guess I need to do a continuity test from the (Com) line to pin 39 in the 50 pin WH-00133 plug at the AV-60000?
 
csmith3603 said:
I replaced the micro switch even when it tested ok. Replaced connectors.
The Switch is normally open! The wind hits it at the right angle and it is closed....Stall light come on.
The airplane is on the ground with the reporting conditions. Thanks
Click to expand...
Ok, time to take a step back…

You disconnected the ground wire to the stall switch and the tone stops, I assume the switch was still installed in place. Please explain how the open contract on the micro switch is allowing the this signal to pass
 
MMiller said:
Ok, time to take a step back…

You disconnected the ground wire to the stall switch and the tone stops, I assume the switch was still installed in place. Please explain how the open contract on the micro switch is allowing the this signal to pass
Click to expand...
Yep the wire is pluged into a common connector and back thru to a so called master bus (AV-60000) that processes it.
This open switch is being tested in the IC chip located on the AV-6000 Van's Aircraft Manufactured master bus design?
The status of the Stall warning on the display HDX is RED. The airplane is on the ground... When the wind hits the vane
the micro switch closes the a stall displays on the HDX in RED. If there was an open circuit there would not be any status
on the Dynon HDX display....
 
csmith3603 said:
Wow. I can believe how Van's builders love electrical problems. I had this same problem years ago!. I think it was you that solved it before you retired.. Grin. Yep you deserve the support fee! I let Van's support know about you pointing out the "STALL" on the display and the wiring problem with the micro switch at the stall indicator. Thanks again Tony! Smile.
Click to expand...
Called Van's Support and they had nothing to suggest. I told them I would check the continuity from the micro switch (com) to pin 39 of the 50 pin WH-00133 going to the AV-60000. Ordered an AV-60000.
 
howdy tony. well i did a continuity check from com wire to pin 39 and was good. i removed the rebuild the stall warning device and plugged
into the wires another micro switch hanging from wires. Squealing gone. Double dog dang!
 
Charles Smith, Please measure the resistance of the suspected defective microswitch between terminals COM and N.O.
Many of us on this forum are anxious to know the measured ohms.
The measurement should be done with no wires attached and without the switch lever being pressed.
 
Mich48041 said:
Charles Smith, Please measure the resistance of the suspected defective microswitch between terminals COM and N.O.
Many of us on this forum are anxious to know the measured ohms.
The measurement should be done with no wires attached and without the switch lever being pressed.
Click to expand...
Howdy there tony. I think it was 3.30 but can,t remember. I did finally get the switch and vane to work again. It was the Stall
Warning. I replace the entire stall warning with one from another aircraft, plus I replaced the clips to the micro switch.
I believe this was the second time thru this problem! Zenith grin.. From the start I thought the vane was bent and some yahoo was checking my
plane out and hooked the vane and bent it... I put some red and white tape around the vane opening to warn yahoo's to walk around it.
 

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