K3 amplifier board gold header mod

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K3 amplifier board gold header mod

Mike K2MK
I received the mod kit for the gold plated pin replacements but I can't find an instruction sheet on the Elecraft site. I really wanted to view the mod before diving into it. Can someone point me to a link. The number on the parts envelope is KPA3CONMDKT.

73,
Mike K2MK
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Re: K3 amplifier board gold header mod

KeithWE6R
Administrator
We are working on instructions to go with the kit. Here are some for now
to get you going.
Keith
The female connectors are already gold plated. But they get damaged and
should be replaced anytime the male connectors are damaged. Or replace
the KPAIO3 board.

The male connector pins can be heated well and then pulled out through
their plastic carrier one by one.  Use a little extra solder to speed
the heating and removal process (you can remove it later). You can
replace just the 6 male pins of the connectors at P68B on the KPA3 and
at P67B on the RF board that carry the 12V current to the KPA3,  if they
are the only ones that look to be damaged. But do check the female
connectors too for signs of high heat, oxidation, and pitting.

You can remove the plastic carrier as with the female connector, to make
it easier to get the pins out one by one.  Then vacuum out the remaining
solder and use desoldering braid to finish the job, followed by a good
cleaning with Q-Tips (cotton swabs) or a cloth moistened with acetone,
alcohol, or flux solvent. Take extreme care to not damage the PCB or any
nearby parts either. Get the connector pins out first, then remove the
solder from the plated through holes. This works better in most cases
than trying to remove the connector intact unless you are truly an
expert at desoldering and have the best desoldering tool made. Make sure
there are no solder bridges remaining between pins and the board is in
good shape before installing the new connectors. Inspect it well under a
bright light with a magnifier.

You should have good desoldering skill and a good desoldering station
like the Pace, Weller, Waasco, Xytronic, OK/Metcal, Aoyue, etc.) or a
Hakko 808 desoldering gun to do this work. Clean the desoldering tool
well  before starting so it works as well as it can.



On 3/1/2012 11:52 AM, Mike K2MK wrote:
> I received the mod kit for the gold plated pin replacements but I can't find
> an instruction sheet on the Elecraft site. I really wanted to view the mod
> before diving into it. Can someone point me to a link. The number on the
> parts envelope is KPA3CONMDKT.
>
> 73,
> Mike K2MK
>
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Re: K3 amplifier board gold header mod

ab2tc
Hi all,

Is the measurement point for the indicated voltage in the DISP menu *after* this potentially bad connector or do I still have to worry about this even if the indicated voltage under full load is good? Mine is excellent, I have only 0.4V drop from receive to full 17A worst case at 100W output.

AB2TC - Knut

Keith wrote
We are working on instructions to go with the kit. Here are some for now
to get you going.
Keith
The female connectors are already gold plated. But they get damaged and
should be replaced anytime the male connectors are damaged. Or replace
the KPAIO3 board.

<snip>
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Re: K3 amplifier board gold header mod

Bruce Beford-2
In reply to this post by Mike K2MK
Knut,
Voltage is sensed on the main board, the power to the PA (via the
troublesome connectors) is tapped off the main board. High resistance on
these connectors do not affect the displayed voltage.
73, Bruce, N1RX

> Is the measurement point for the indicated voltage in the DISP menu
> *after* this potentially bad connector or do I still have to worry
> about this even if the indicated voltage under full load is good?
> Mine is excellent, I have only 0.4V drop from receive to full 17A
>  worst case at 100W output.

> AB2TC - Knut



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Re: K3 amplifier board gold header mod

Bruce Beford-2
In reply to this post by Mike K2MK
Sorry, My mistake. I went back to the schematics, and it looks like the 12V
level is sensed from the PA board, which would be after the suspect
connectors. Unfortunately, there is often no symptom until they
corrode/overheat enough to cause problems.

I apologize for my earlier misinformation. I should have double-checked the
schematics first.
73,
Bruce, N1RX

> Knut,
> Voltage is sensed on the main board, the power to the PA (via the
> troublesome connectors) is tapped off the main board. High resistance on
> these connectors do not affect the displayed voltage.
> 73, Bruce, N1RX




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