[RFI] Whirlpool Duet Washing Machine RFI update
Tyler Stewart
k3mm at comcast.net
Fri Feb 11 18:07:55 EST 2005
I'm not saying mine is quiet, I"m just saying that I havent noticed or
identified any problem from it. My nearest antennas are about 150 feet away
on a tower and they are all triband KLM's for the upper bands. I do have
misc. manmade noises, but usually none that really knocks me out on an all
but a dead band.
Tyler K3MM
----- Original Message -----
From: "Leigh L Klotz, Jr." <Leigh at WA5ZNU.org>
To: "Pete Smith" <n4zr at contesting.com>; <rfi at contesting.com>;
<k3mm at comcast.net>
Sent: Friday, February 11, 2005 12:14 PM
Subject: Re: [RFI] Whirlpool Duet Washing Machine RFI update
> Thank you Pete and Tyler.
>
> It is not in warranty -- I got a few levels up on the phone and thry said
> as a "goodwill gesture" they would send me new parts. They also said that
> the front panel is unshielded (which is where I pick up the noise from)
> and that they had nothing else to do if this didn't fix it.
>
> On the other hand, since Tyler K3MM's Duet is quiet so maybe I will give
> it a go. Mine interferes with an FM broadcast boombox running in
> batteries as well as my K2 and FT-817 on a doublet, and I have messed
> around with grounding to no avail. I am not hopeful though...
>
> 73,
> Leigh / WA5ZNU.
>
> On Fri, 11 Feb 2005 7:18 am, Pete Smith wrote:
>> Leigh, do I understand correctly that these parts haven't yet been
>> installed? If so, my suggestion would be to let them install them in the
>> stock fashion and see what happens to your noise problem. If they went
>> to this much trouble to fix it, the new control system may be clean. By
>> all means DON'T mess around with shielding or beads until you know -- I
>> suspect doing anything like that could void your warranty.
>>
>> 73, Pete N4ZR
>>
>> At 08:40 PM 2/10/2005, Leigh L. Klotz, Jr. wrote:
>>
>>> Here is an update on my Whirlpool Duet problem.
>>>
>>> I have a Whirlpool Duet front-loading washer, which I think uses a
>>> variable-frequency AC motor and a fairly complicated mpu control system.
>>> I've reported this here before, and also have talked to the Whirlpool
>>> people. I now have a new set of innards, and the new news here is
>>> pictures of them at http://wa5znu.org/2005/01/duet/parts/
>>>
>>> I am seeking advice as to whether I should try shielding them with
>>> copper tape or foil, or at the very least putting some ferrite beads on
>>> the control cables, or if I should just let nature take its course and
>>> let the service people put in the new parts as is.
>>>
>>> Also, if anybody has recommendations for RF-quiet front-loading washers,
>>> my wife has fortunately agreed that if the problem can be solved by
>>> selling this unit and buying a new one, we can do that. (If you would
>>> like to buy a slightly used Whirlpool Duet spark gap transmitter, works
>>> on all bands, please contact me offlist, hi hi.)
>>>
>>> Details below.
>>>
>>> 73,
>>> Leigh WA5ZNU
>>>
>>> *Kinds of Noise*
>>>
>>> The washer makes at least 3 kinds of noise.
>>> 1. When it's off or on, there's some hash.
>>> I assume this is from a switching power supply, or possibly the MPU.
>>> I don't have images of this noise off and on.
>>>
>>> 2. When the drum is spinning, it makes both broad noise and discrete
>>> noise about every 17KHz
>>> The noise extends up well past 20M. I have audio spectrum images at
>>> http://wa5znu.org/2005/01/duet/noise/
>>>
>>> You can see the discrete noise clearly in the 4th and 7th images. To
>>> the left of the blue line is foreign BCB. To the right is the discrete
>>> noise starting.
>>>
>>>
>>> The broad noise "washes out" everything for me, and the discrete noise
>>> is maybe 10dB above that.
>>> You can see the effect of the broad noise effect in the 3rd and 5th
>>> images on the web page. The weak PSK signal disappears when the noise
>>> starts. The rolloff below 500 and above 2500Hz is system audio
>>> response.
>>>
>>> 3. It makes other discrete noise when the water pump is running.
>>>
>>> *Sources of noise*
>>> I took my Elecraft KX1 with a short piece of wire as an antenna and
>>> found that little noise came from the power cable.
>>> However, tremendous noise came from the front panel. In fact, I can
>>> pick it up there on a cheap FM broadcast radio with no antenna.
>>> There is much less noise to the sides of the washer, where metal is
>>> between it and the front panel.
>>>
>>> *What I've done so far
>>> *A Radio Shack AC line filter did nothing but it did show me that the
>>> 3rd prong is grounded.
>>> An ohmeter shows <1 Ohm between the 3rd prong and the water pipes.
>>> Bonding the washer 3rd prong to the water pipe did nothing.
>>>
>>> *What Whirlpool did
>>> *Whirlpool said that their Part 15 data was proprietary.
>>> I checked and appliances (except microwaves) are not required to be
>>> submitted for certification.
>>> Sure enough, Whirlpool has FCC Part 15 data filed with the FCC only for
>>> microwaves.
>>>
>>> Whirlpool said that the control board and front panel are unshielded.
>>> They spent a bit of time talking to me on the phone, and their engineers
>>> looked at my audio spectra. They sent me a new set of innards -- motor,
>>> control board, AC line filter, and front panel, for free (out of
>>> warranty) and said that if that didn't fix it they didn't know what to
>>> do. They said the controller is made in Germany, but that it is not
>>> sold in the EU (I thought maybe they'd designed it for CE but removed
>>> parts not required.) They said this is their 3rd product with an MPU
>>> instead of a mechanical controller. They also said they have no other
>>> RFI reports so far.
>>>
>>> I have pictures of the parts at http://wa5znu.org/2005/01/duet/parts/
>>>
>>> *What do I do now?*
>>> So I think the service call is going to be on my dime, and I don't know
>>> what to do next.
>>>
>>> 1. Call and have the new parts installed and probably get no result.
>>> 2. Try to retrofit copper shielding into the control board box and front
>>> panel and hope the service installer doesn't notice.
>>> 3. Clamp a few ferrites on the wires in the front panel and hope for the
>>> best.
>>> 4. Do #1, but if there is no result, try to get the ARRL or the FCC
>>> involved.
>>> 5. Sell the washer and buy a different brand that might or might not
>>> generate RFI.
>>>
>>>
>>> _______________________________________________
>>> RFI mailing list
>>> RFI at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/rfi
>
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