Steve,
Seen many of these, it is a shorting ring on a ultra high gain (my
guess) jfet or op-amp that has no front end protection. At the used
to place we had a radiation instrument mfg by Eberline called an RO-2,
the only amp was an ultra sensitive op-amp that was mounted dead bug
style, one inverted it soldered the leads to it then clipped off the
shorting ring, I can attest that if it is not done this way you go get a
new one. The other style I have seen is a tapered coiled spring like
what is inside a wire nut with the leads twisted together. The little
loop is so it can be soldered in then the loop is pulled to remove the
short, do not under any circumstances remove the short before it is
soldered in place, and never touch the leads. It is designed to be
mounted off the board, leads trimmed following soldering. Even high
humidity and stringent ESD protections won't help. We went through
these by the droves until we found out the warehouse was opening the
sealed cans they come in and looking to see if they were in there, not
touching but looking and not being grounded, they come in a 2" diameter
sealed metal can mounted in an ESD cardboard support in the center of
the can. They are only 3/8" in diameter.
Pat Goodyear
Retired Control Tech.
On Fri, Aug 8, 2014 at 8:58 AM, Steve Gregory wrote:
> Hi again all!
>
> Well, I have learned something this morning! But I learned something
> else
> too, this little jewel will have to be stood up a little somehow
> because
> the footprint is such that it will drop down flush to the board and
> then
> have a possibility of the case shorting to the pads:
>
> http://stevezeva.homestead.com/SD211DE_Footprint.jpg
>
> There's no insulator called out in the BOM, and worse yet, these parts
> have
> already been prepped without taking into account a stand-off height
> for the
> part......(heavy sigh). Well I suppose if there wasn't problems, I
> wouldn't
> have a job.....('nuther heavy sigh)
>
> Steve
>
>
> On Fri, Aug 8, 2014 at 9:23 AM, Ed Popielarski
> <[log in to unmask]>
> wrote:
>
>> Old school ESD protection. We're talking about '70s stuff here.
>> Remove it
>> in an ESD protected environment and throw it away. It's a dead short
>> between leads and should not be soldered in place.
>>
>> Ed Popielarski
>> Engineering Manager
>>
>>
>> 970 NE 21st Ct.
>> Oak Harbor, Wa. 98277
>>
>> Ph: 360-675-1322
>> Fx: 206-624-0695
>> Cl: 949-581-6601
>>
>> “It's one kind of victory to slay a beast, move a mountain,
>> and
>> cross a chasm, but it's another kind altogether to realize that the
>> beast,
>> the mountain, and the chasm were of your own design.”
>>
>>
>> https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A
>>
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
>> Sent: Friday, August 08, 2014 8:08 AM
>> To: [log in to unmask]
>> Subject: [TN] Unusual part thingy....
>>
>> Morning All,
>>
>> One of my inspectors was doing a first article inspection on a board
>> and
>> came to me with a question about a transistor that is on the board,
>> it's
>> this one here:
>>
>>
>>
>> http://www.futureelectronics.com/en/technologies/semiconductors/discretes/transistors/mosfets/Pages/3792082-SD211DE.aspx?IM=0
>>
>> She was asking me what this little wire thingy is on the leads of the
>> part, I said I didn't know...I have never seen something like this
>> before.
>> I'm thinking that it may be some sort of stand-off that you slide up
>> and
>> down the leads depending on how high you want the part to be stood up
>> off
>> the board, but I'm not sure. The datasheet doesn't say anything about
>> it,
>> and like I said, this is the first time I've seen this (okay, I've
>> lead a
>> sheltered life... ;^) )
>>
>> So what is this thingy?
>>
>> http://stevezeva.homestead.com/SD211DE.jpg
>>
>> Steve
>>
>> --
>>
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