From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Update on EMI problem.
Date: Wed, 15 Jan 2020 22:06:06 +0800
References: <list-13392005@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-13392005@logan.com>
Message-Id: <150C1D89-9445-4D6C-8D9D-0AAB38C3C2B3@gmail.com>

Hi Finn

I only went for them as I understood others had suffered a similar =
symptom and this was Tracy=E2=80=99s recommended fix.
I=E2=80=99ve got more ferrites coming and I=E2=80=99ll be putting these =
on all inputs to the EC2 and ADHARS and at the feed point of the =
antenna.
I=E2=80=99ll feedback what I discover.

Cheers
Steve

> On 15 Jan 2020, at 9:02 pm, Finn Lassen finn.lassen@verizon.net =
<flyrotary@lancaironline.net> wrote:
>=20
> Did you trace the circuit? Any chance there's already caps on the =
board on your version of the EC2?
>=20
> Again, I don't see the need for the caps. Especially because your =
problem was only with controller A.
>=20
> I would start with temp input or serial input.
>=20
> Finn
>=20
> On 1/14/2020 11:23 PM, Stephen Izett stephen.izett@gmail.com wrote:
>> A frustrating few hours
>>=20
>> I got down to the hanger this morning to look into the EMI in both =
the engine controller and EFIS.
>>=20
>> First thing I did was reroute the radio coax so that instead of being =
in close proximity to many cables down the centre of the aeroplane =
instead down the very right hand side.
>> This increased the distance to various wire looms by ~450mm.
>>=20
>> Prior to this change the symptom outside the hangar was from memory =
about a 300ft/min vertical speed on tx in the Skyview EFIS.
>>=20
>> First test with radio tx after the reroute of coax inside the hangar =
yielded a "4 times worse" symptom in the EFIS! ~1300ft/min reading on =
tx.
>>=20
>> I then tried the test outside and away from the metal hangar by 10m =
and the symptom was reduced to ~600ft/min and increase in symptoms of =
about 100% on original problem.
>> I then applied a clamp on ferrite to the cable loom entering the =
ADHARS unit from where the symptom originates.
>> On tx outside the hangar again the symptoms are far reduced by over =
1/2.
>>=20
>> So if I had left the radio coax where it was, the ferrite may have =
fixed the problem in the EFIS.
>> I have more ferrites on order and they appear to be very effective, =
so will use these to attenuate the RF entering the various pieces of =
equipment.
>> EMI trouble shooting is indeed a black art!!
>>=20
>> I also removed the Engine Control unit and soldered 0.1uF ceramics =
across the outputs to earth of the MAP sensors of both A and B computers =
as specified by Tracy.
>> On reinstalling the Engine Control unit I was not able to start the =
engine!
>> It would fire but not run on either controller.
>> So spark and fuel are present, but not to remain running.
>>=20
>> So the mod appears to have messed up the MAP sensing.
>> My initial thought was that the caps were actually resistors packaged =
wrongly but they measure open circuit.
>>=20
>> So the few hours of mods and testing has been exceedingly =
frustrating, going backwards at every turn except for the 1 ferrite =
showing itself to be very effective.
>>=20
>> I=E2=80=99m hoping my next outing will be very much more fruitful.
>> In the mean time I=E2=80=99ll ponder what could possibly cause both =
Computers in the Engine Controller to be u/s.
>> If I cannot discover my deliberate mistake. I=E2=80=99ll remove the =
caps and retest the Controller on Friday.
>>=20
>> Cheers
>>=20
>> Steve
>>=20
>>=20
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   =
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>=20
>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
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