[RFI] Whirlpool Duet Washing Machine RFI update

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.
>>>
>>>
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>>> RFI at contesting.com
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> 