KPA100 U1 pin 3 -> ground | failure

[dave.wilburn]

During the initial tests (from the right side of page 21 in the KPA100
manual) on U1 pin 3 -> ground, I measured just under 4k as opposed to
the > 10k.

I pulled out the schematic and checked pins 3 and 4 of the R-pack, and
they measured correctly.  When I checked Q11, I read a bit over 100 ohms
across the source and drain in both directions.  I pulled Q11 and the
reading on U1 pin 3 went to greater than 10k.  I measured both
directions of S & D on Q11 once it was out, and still read about 120 ohms.

I get the impression this is not good.
--

David Wilburn
[hidden email]
K4DGW
K2 #5982
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[Don Wilhelm-3]

Dave,

Yes, that is not good - you need a new 2N7000.  Those FETs are quite
sensitive to static and likely became zapped at some point.

Send a note to Elecraft ([hidden email]) and request a new one.

73,
Don W3FPR

David Wilburn wrote:

> During the initial tests (from the right side of page 21 in the KPA100
> manual) on U1 pin 3 -> ground, I measured just under 4k as opposed to
> the > 10k.
>
> I pulled out the schematic and checked pins 3 and 4 of the R-pack, and
> they measured correctly.  When I checked Q11, I read a bit over 100 ohms
> across the source and drain in both directions.  I pulled Q11 and the
> reading on U1 pin 3 went to greater than 10k.  I measured both
> directions of S & D on Q11 once it was out, and still read about 120 ohms.
>
> I get the impression this is not good.

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