Folks, I've sent pics to Steve.
Inge

----- Original Message ----- 
From: "stephen gregory" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, January 14, 2011 4:36 PM
Subject: Re: [TN] a different Friday quiz


Inge, send me a picture and I'll post it...

Steve

--- On Fri, 1/14/11, Inge <[log in to unmask]> wrote:


From: Inge <[log in to unmask]>
Subject: Re: [TN] a different Friday quiz
To: [log in to unmask]
Date: Friday, January 14, 2011, 8:45 AM


It looks like Steve got no time to fix the photos for you this day.

Inge



----- Original Message ----- From: "Inge" <[log in to unmask]>
To: "TechNet E-Mail Forum" <[log in to unmask]>
Sent: Friday, January 14, 2011 3:40 PM
Subject: Re: a different Friday quiz


>
>
> Yes, I know that, have been analyzing a lot during the years, but this 
> seems
> a little different. Note: 1. the unit has never been exposed to any other
> environment than inhouse atmosphere.
> 2. The screw is not in contact with anything else than copperless FR-4.
> 3. Only one screw has this corrosion.
>
> Inge
>
>
>
> On 14 January 2011 12:07, Mike Fenner <[log in to unmask]> wrote:
>
> Some corrosion, once started, can self perpetuate by feeding on atmosphere
> water and CO2, with no need for differential metals etc.
>
> Regards
>
>
> Mike
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Eric Christison
> Sent: Friday, January 14, 2011 10:48 AM
> To: [log in to unmask]
> Subject: Re: [TN] a different Friday quiz
>
> I'd go for galvanic corrosion in a mildly corrosive atmosphere, or
> possibly highly corrosive depending upon your taste in food.
>
> You didn't ever drop it in a bowl of Kimchi did you, or that Icelandic
> dish of basking shark marinated in caustic soda?
>
> Imagine periods of high humidity and temperature changes where moist
> contaminated (salty?) air is drawn into the enclosure where it condenses
> on the screw head. I bet you have dissimilar metals connected together
> which will cause corrosion and the condensing air will drip off the
> screw head to move the corrosion products around the inside of the device.
>
> Regards,
>
>
>
>
>
> ----- Original Message ----- From: "Inge" <[log in to unmask]>
> To: "TechNet E-Mail Forum" <[log in to unmask]>
> Sent: Friday, January 14, 2011 12:06 AM
> Subject: a different Friday quiz
>
>
>>
>> I bought a digital temperature equipment, consisting of a inhouse table
>> unit and a outdoors unit. Cost = 25 USD. Cheap? Yes. But let's have a 
>> look
>> on inside after the problem, which started just a few weeks. You can read
>> the inside temperature, clock works, date works, and you can use the 
>> alarm
>> and shift between the four channels, but the receiver does not take in 
>> the
>> signals from the little sender on the wall any more. I dismantled the box
>> and marvelled when I saw the shit I payed for. It's a wonder that there
>> are any functions working at all! Now, what caused the dead receiver was 
>> a
>> flow of iron from one screw (upper left corner ) . There is a bridge of
>> corrosion products (brown and green) from the screw to the thermistor
>> (RT) continuing to the rest of the circuitry. When I washed the card and
>> dried it, the reciever worked again,
>>
>> Now, folks, here comes a question for the sharp TNetters:
>>
>> "How can the screw be so rusty and deliver iron ions when it's not
>> connected to anything? It's just torqued into the plastic body. The other
>> screws are identical, but have not been involved in anything. "
>>
>> The box has been on the kitchen table and has not been exposed to 
>> humidity
>> or any else abnormal condition.
>>
>> The two 1.5 V batteries are removed on the pics.
>>
>> Hope the gregorian Steve will help me with the photos.
>>
>> /Inge
>>
>>
>>
>>
>>
>>
>>
>


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to 
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to 
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site 
http://www.ipc.org/ContentPage.aspx?Pageid=E-mail-Forums for additional 
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 
ext.2815
-----------------------------------------------------

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to 
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to 
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site 
http://www.ipc.org/ContentPage.aspx?Pageid=E-mail-Forums for additional 
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 
ext.2815
----------------------------------------------------- 


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/ContentPage.aspx?Pageid=E-mail-Forums for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------