K3 - KPAIO3 'Puller'

[Tom Hammond-2]

Recently, I had to open up my K3 in order to perform a bit of
preventive maintenance, on the KPAIO3 PC board.  This is the small PC
board which interfaces the KPA3 100W amp assembly to the RF board in
the Elecraft K3 HF transceiver.

The job started off easy enough... remove the top cover, remove the
rear cooling fan assembly, remove the KPA3 PC board... I mean, it was
an easy thing to do... a small PC board... couldn't be all THAT
difficult to pull it straight up and out of the case,
right?  WRONG!  In order to ensure that the KPA3 doesn't accidentally
come loose during transport and handling, Elecraft chose to use some
REALLY husky dual-row multi-pin 'hi retention' headers to attach the
KPAIO3 to the RF board, and the same headers to attach the KPA3 to
the KPAIO3.  The only difference is that if you must remove the KPA3
from the clutches of the KPAIO3, you have a bit more available 'real
estate' to grasp (and pry) on than you do when it comes to removing
the KAPIO3 board.  In fact, there was a point in time that I was
absolutely certain that my KPAIO3 had been soldered directly to the
RF board, it was that tightly held in place.

Before I went too far and found myself ripping the guts of the RF
board out (because my KPAIO3 really WAS soldered to the RF board), I
called Elecraft and spoke with one of their techs who was very
familiar with the K3.  Let me digress just a bit here... I did build
my K3 from a kit, but being serial #00008 (and one of the first K3's
out of Aptos), it had been quite a while since the assembly, and I
didn't recall whether I'd installed my KPAIO3 or whether it'd been
pre-installed at the factory... so I called to confirm my
suspicions... that it really DID plug in.

The tech assured me that it did plug into the RF board and he agreed
that it was a 'bear' to remove.  He suggested 'wiggling' the PC board
(front-to-back) as I lifted it up, ever so gradually allowing it to
'work' itself out of the death grip of the two headers.  I considered
that scenario, but didn't care for the 'wiggling' part, feeling that
this only contributed to a possibly fractured PC board joint on one
(or more) of the header pins...

The tech also suggested using some 'heavy wire' to make a loop to go
through two (2) available  (and unused) holes in the KPAIO3 PC board,
with the loop tied together so I could lift on it and pull the PC
board straight out.

THIS IDEA I LIKED...!

I did a quick search of the shack and found little heavy wire, BUT I
did manage to locate what turned out to be a length of 0.125" (1/8")
O.D. aluminum welding rod.

I checked that the rod just barely passed through the (2) holes in
the KPAIO3 PC board and was gratified to find that it did.

I then took a few measurements and bent the rod into the lift bracket
shown below (note that the two vertical legs are different lengths),
cutting off the excess rod length after the final bend had been
made.  I then used a fine file to smooth out any 'dings' I might have
created in the two short 'feet' of the lift bracket, to ensure that
they would insert easily into the two PC board holes.

Now, all I have to do is to slip the two 'feet' of the lifting
bracket into the holes of the KPAIO3 PC board, grip the lifting
bracket AND the top bar of the K3 rear panel and squeeze my
hand!  The PC board pops out cleanly and quite easily.  And much more
safely than were I to have to 'wiggle' things back 'n forth.

While I don't expect everyone to have 1/8" O.D. aluminum welding rod
on hand, I'm pretty certain that the same device could be made using
a fairly heavy gauge metal clothes hangar.  The IMPORTANT thing is,
when using this device, keep the main body of the lifting bracket up
flush against the PC board,  thereby reducing the stress on the feet
and keeping them from bending.

A PDF with this article and dimensional illustrations of the KPAIO3
Puller is available on my web site at:

   http://www.n0ss.net/index_k3.html

more specifically:

   http://www.n0ss.net/kpaio3_pcb_puller_v1r1.pdf

73,

Tom Hammond   N0SS

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Dave, W8OV]

Tom,

Thanks for the tip and diagram.  I'll file that one for possible use later.

--Dave, W8OV

On 4/20/2010 6:08 AM, Tom Hammond wrote:

>
>     http://www.n0ss.net/kpaio3_pcb_puller_v1r1.pdf
>
> 73,
>
> Tom Hammond   N0SS
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Bill VanAlstyne W5WVO]

Tom, wish I had had benefit of your invention a week ago, when I had to
replace my defective KPAIO3 board. Without benefit of instruction of any
sort, I just started in removing stuff that looked like it was in the way...
I ended up removing quite a bit of stuff! The board eventually did come out,
with the benefit of a good deal of that "wiggling" that you didn't like the
sound of.

Putting the new KPAIO3 board back in was even more difficult than getting
the old one out, but I was finally able to find the correct angle to slip
the board into insertion position past numerous obstacles. I was 90% sure
that if the new KPAIO3 fixed the original problem, it would be a miracle,
and that I had probably blown up all kinds of stuff with my necessarily
aggressive pushing, prying, and pulling. However, when it was all back
together, the original RF power problem was fixed, everything worked, I was
relieved and happy -- and probably lucky.

BTW, I did NOT build my K3; it was a factory job. I could have benefited
from the experience, I'm sure.

FWIW (in case this failure mode sounds suspiciously familiar to anybody),
the original problem that prompted the replacement was a barely-intermittent
(mostly fail mode) KPA3 power fault, where the K3 thought there was no 12VDC
available for the power amplifier, and put itself into low-power mode as if
the KPA3 wasn't installed. When completely cold and freshly powered up, the
KPA3 would function for maybe one or two transmission periods, but on the
next key-up, it would fail again and wouldn't come back without extended
R&R. :-)

The Elecraft techs felt it was probably a bad 12V sensor device on the
KPAIO3, and it appears they were correct. No more problems after a week+ of
operation.

Bill W5WVO


--------------------------------------------------
From: "Tom Hammond" <[hidden email]>
Sent: Tuesday, April 20, 2010 5:08 AM
To: <[hidden email]>
Subject: [Elecraft] K3 - KPAIO3 'Puller'

> Recently, I had to open up my K3 in order to perform a bit of
> preventive maintenance, on the KPAIO3 PC board.  This is the small PC
> board which interfaces the KPA3 100W amp assembly to the RF board in
> the Elecraft K3 HF transceiver.
>
> The job started off easy enough... remove the top cover, remove the
> rear cooling fan assembly, remove the KPA3 PC board... I mean, it was
> an easy thing to do... a small PC board... couldn't be all THAT
> difficult to pull it straight up and out of the case,
> right?  WRONG!  In order to ensure that the KPA3 doesn't accidentally
> come loose during transport and handling, Elecraft chose to use some
> REALLY husky dual-row multi-pin 'hi retention' headers to attach the
> KPAIO3 to the RF board, and the same headers to attach the KPA3 to
> the KPAIO3.  The only difference is that if you must remove the KPA3
> from the clutches of the KPAIO3, you have a bit more available 'real
> estate' to grasp (and pry) on than you do when it comes to removing
> the KAPIO3 board.  In fact, there was a point in time that I was
> absolutely certain that my KPAIO3 had been soldered directly to the
> RF board, it was that tightly held in place.
>
> Before I went too far and found myself ripping the guts of the RF
> board out (because my KPAIO3 really WAS soldered to the RF board), I
> called Elecraft and spoke with one of their techs who was very
> familiar with the K3.  Let me digress just a bit here... I did build
> my K3 from a kit, but being serial #00008 (and one of the first K3's
> out of Aptos), it had been quite a while since the assembly, and I
> didn't recall whether I'd installed my KPAIO3 or whether it'd been
> pre-installed at the factory... so I called to confirm my
> suspicions... that it really DID plug in.
>
> The tech assured me that it did plug into the RF board and he agreed
> that it was a 'bear' to remove.  He suggested 'wiggling' the PC board
> (front-to-back) as I lifted it up, ever so gradually allowing it to
> 'work' itself out of the death grip of the two headers.  I considered
> that scenario, but didn't care for the 'wiggling' part, feeling that
> this only contributed to a possibly fractured PC board joint on one
> (or more) of the header pins...
>
> The tech also suggested using some 'heavy wire' to make a loop to go
> through two (2) available  (and unused) holes in the KPAIO3 PC board,
> with the loop tied together so I could lift on it and pull the PC
> board straight out.
>
> THIS IDEA I LIKED...!
>
> I did a quick search of the shack and found little heavy wire, BUT I
> did manage to locate what turned out to be a length of 0.125" (1/8")
> O.D. aluminum welding rod.
>
> I checked that the rod just barely passed through the (2) holes in
> the KPAIO3 PC board and was gratified to find that it did.
>
> I then took a few measurements and bent the rod into the lift bracket
> shown below (note that the two vertical legs are different lengths),
> cutting off the excess rod length after the final bend had been
> made.  I then used a fine file to smooth out any 'dings' I might have
> created in the two short 'feet' of the lift bracket, to ensure that
> they would insert easily into the two PC board holes.
>
> Now, all I have to do is to slip the two 'feet' of the lifting
> bracket into the holes of the KPAIO3 PC board, grip the lifting
> bracket AND the top bar of the K3 rear panel and squeeze my
> hand!  The PC board pops out cleanly and quite easily.  And much more
> safely than were I to have to 'wiggle' things back 'n forth.
>
> While I don't expect everyone to have 1/8" O.D. aluminum welding rod
> on hand, I'm pretty certain that the same device could be made using
> a fairly heavy gauge metal clothes hangar.  The IMPORTANT thing is,
> when using this device, keep the main body of the lifting bracket up
> flush against the PC board,  thereby reducing the stress on the feet
> and keeping them from bending.
>
> A PDF with this article and dimensional illustrations of the KPAIO3
> Puller is available on my web site at:
>
>   http://www.n0ss.net/index_k3.html
>
> more specifically:
>
>   http://www.n0ss.net/kpaio3_pcb_puller_v1r1.pdf
>
> 73,
>
> Tom Hammond   N0SS
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html