short circuit varactor diodes 1SV149

[Steef PA2A]

Today I soldered the 6 MV209 varactor diodes and the 11 1SV149 's on the RF-board of my K2 #4654 According to the text on page 50 the varactor diodes should be pressed all the way down on the board to prevent stray signal coupling. The SV149 varactors may have a center lead that has been cut flush with the body of the device.

The center leads are clearly visible, about 0.5 mm coming out of the varactor bodies! The soldering islands for the two varactor leads have a very narrow gap, not more than half a mm on top of the board. The center pin can easily short against one or even both leads of the 1SV 149 's. I left them about one mm above the board.

73 's Steve
K2 #4654
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[Chris-488]

You almost gave me a heart attack; I had just finished putting the
SV149s in #4768 this morning. I snugged them down tight to the board. So
I ran off to the bench and checked with the meter, but all mine are fine.

I had assumed that the middle leg was just something left over from a
manufacturing run where they had used transistor tooling, but with a
transistor inside. Your comments made me think that maybe they are
transistors with a leg missing.

Perhaps somebody who hasn't installed theirs yet could check with a
meter? Or does somebody know what is actually inside the package?

Had to break off this afternoon to attend a nephews birthday party and
do some token woodworking in the bathroom that I am supposed to be
renovating, but got back to the bench this evening and have just
finished the crystals - first toroid winding session tomorrow.

Chris VP8BKF

PA2A Steef wrote:

>Today I soldered the 6 MV209 varactor diodes and the 11 1SV149 's on the RF-board of my K2 #4654 According to the text on page 50 the varactor diodes should be pressed all the way down on the board to prevent stray signal coupling. The SV149 varactors may have a center lead that has been cut flush with the body of the device.
>
>The center leads are clearly visible, about 0.5 mm coming out of the varactor bodies! The soldering islands for the two varactor leads have a very narrow gap, not more than half a mm on top of the board. The center pin can easily short against one or even both leads of the 1SV 149 's. I left them about one mm above the board.
>  
>

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[Don Wilhelm-3]

Chris and all,

This is another one of those subjects that come up from time to time - and
each time, the answer is -- Don't Worry -- Even if that VERY short varactor
leg is connected inside (unlikely, but I don't really know), the insulation
afforded by the RF Board masking is sufficient to provide adequate
insulation.  So just put those 1SV149s down close to the board - of course,
don't force them and scrape off the PC board masking in the process - just
use good old fashioned common sense.

73,
Don W3FPR

> -----Original Message-----
>
> You almost gave me a heart attack; I had just finished putting the
> SV149s in #4768 this morning. I snugged them down tight to the board. So
> I ran off to the bench and checked with the meter, but all mine are fine.
>
> I had assumed that the middle leg was just something left over from a
> manufacturing run where they had used transistor tooling, but with a
> transistor inside. Your comments made me think that maybe they are
> transistors with a leg missing.
>
> Perhaps somebody who hasn't installed theirs yet could check with a
> meter? Or does somebody know what is actually inside the package?
>
> Had to break off this afternoon to attend a nephews birthday party and
> do some token woodworking in the bathroom that I am supposed to be
> renovating, but got back to the bench this evening and have just
> finished the crystals - first toroid winding session tomorrow.
>
> Chris VP8BKF
>
> PA2A Steef wrote:
>
> >Today I soldered the 6 MV209 varactor diodes and the 11 1SV149
> 's on the RF-board of my K2 #4654 According to the text on page
> 50 the varactor diodes should be pressed all the way down on the
> board to prevent stray signal coupling. The SV149 varactors may
> have a center lead that has been cut flush with the body of the device.
> >
> >The center leads are clearly visible, about 0.5 mm coming out of
> the varactor bodies! The soldering islands for the two varactor
> leads have a very narrow gap, not more than half a mm on top of
> the board. The center pin can easily short against one or even
> both leads of the 1SV 149 's. I left them about one mm above the board.
> >
> >
>

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