True, and they would certainly bugger up the characteristic impedance of 
transmission lines, even as low as 50 ohms.

Brian

On 04/06/2012 16:21, Karen Tellefsen wrote:
> With RF signals, not only are resistive losses (low SIR) important, but
> also capacitive losses.  Hence, no-clean flux residues that have good
> behavior with respect to high SIR, may no be as good with regard to
> capacitive losses.
>
> Karen Tellefsen - Electrical Testing
> Alpha / 109 Corporate Blvd./ S. Plainfield, NJ 07080
> [log in to unmask]
> 908-791-3069
>
>
>
>
> From:   Brian Ellis<[log in to unmask]>
> To:<[log in to unmask]>,
> Date:   06/02/2012 02:04 AM
> Subject:        Re: [TN] Cleaning PCB Assemblies
> Sent by:        TechNet<[log in to unmask]>
>
>
>
> I'm surprised that you think Ensolv can even look at no-clean product
> fluxes more than cosmetically. It is based on n-propyl bromide which has
> general characteristics similar to trichloroethylene but is more toxic
> (central nervous and reproductive systems), a suspected carcinogen and
> depletes the ozone layer (the Parties to the Montreal Protocol have not
> entered it in the list of controlled substances but their wording is to
> discourage its use). It cannot be guaranteed to remove all the
> components in your flux residues and it may leave an invisible monolayer
> of one or more of them, some of which may be hygroscopic, which would
> explain poor RF performance.
>
> Have you performed SIR/ECM tests?
>
> As Bev says, cleaning no-clean makes no sense. If you wish to clean (or
> have to), use flux systems specifically designed for easy cleaning. A
> good aqueous cleaner is second to none, as I have stated since the 1960s!
>
> Brian
>
> On 02/06/2012 02:49, [log in to unmask] wrote:
>> Hi Folks!!  Could use some help.  We are a contract mfg. using no-clean
> solder paste and roll solder
>> for secondary ops and touch-up.  Some of the PCB assemblies contain RF
> components and we have
>> had a customer voice some concerns regarding our cleaning (using
> EnSolv).  Have heard that new
>> chemistries with a aqueous washing system have been successful.  Have
> also heard a vapor degreaser
>> works well but not the greatest choice with RF components.
>>
>> Would appreciate being pointed in the right direction.
>>
>> Thanks in advance for your help!!!!!
>>
>> Regards,
>> Bill
>>
>>
>>
>>
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