Bad KPA100 PCB?

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Bad KPA100 PCB?

GS-3
Hello!

I am just in the process of building my KPA100. And I discover more and more solder points on the PCB where the solder is not accepted. Scraping the pads a bit helps a bit but I don't think this is a solution.

Some details. I don't know where in the process it started but right now I'm on page 15 soldering the capacitors. And it's nearly every third hole that doesn't work. The solder sticks to the leads or the iron.

I use the same iron and solder as with the other 10 PCBs of elecraft that I have built.

I contacted elecraft about this issue but I wanted to ask if others have this problem too? What can I do?

73

Gerhard Schwanz
DH3FAW
mailto:[hidden email]
http://www.gs-personal.de


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RE: Bad KPA100 PCB?

Keith Regli
 I had a similar experience with my recently completed K2/100.  The KPA100
board was the only one with the issue.  It seemed to me that very few of the
components were very delicate, so I increased the heat of the iron a bit and
was able to get the pads to accept solder.  Just be careful on the few
delicate components.  In the end everything worked out fine.

Keith Regli (K7KAR)
mailto:[hidden email]
http://www.kregli.com
 
-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Gerhard Schwanz
Sent: Friday, January 28, 2005 7:06 AM
To: [hidden email]
Subject: [Elecraft] Bad KPA100 PCB?

Hello!

I am just in the process of building my KPA100. And I discover more and more
solder points on the PCB where the solder is not accepted. Scraping the pads
a bit helps a bit but I don't think this is a solution.

Some details. I don't know where in the process it started but right now I'm
on page 15 soldering the capacitors. And it's nearly every third hole that
doesn't work. The solder sticks to the leads or the iron.

I use the same iron and solder as with the other 10 PCBs of elecraft that I
have built.

I contacted elecraft about this issue but I wanted to ask if others have
this problem too? What can I do?

73

Gerhard Schwanz
DH3FAW
mailto:[hidden email]
http://www.gs-personal.de


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Re: Bad KPA100 PCB?

Don Wilhelm-3
In reply to this post by GS-3
Gerhard,

I have found the KPA100 is more difficult to solder than other Elecraft
kits, but I believe it is bacause that  PC board uses thicker copper than
the other kits and is especially noticable when soldering to a grounded pad.

I increase the temperature on my soldering station to 750 to 800 degrees F.
(400 to 430 degrees C.) and have no problem.  The KPA100 manual states that
a low wattage 800 degree F. soldering iron is required.

Try increasing the temperature of your iron.  Judging by your photo, I can
definitely state that your iron is not hot enough, and the pads that give
you the most trouble are the ground points.

73,
Don W3FPR

----- Original Message -----

I am just in the process of building my KPA100. And I discover more and more
solder points on the PCB where the solder is not accepted. Scraping the pads
a bit helps a bit but I don't think this is a solution.

Some details. I don't know where in the process it started but right now I'm
on page 15 soldering the capacitors. And it's nearly every third hole that
doesn't work. The solder sticks to the leads or the iron.

I use the same iron and solder as with the other 10 PCBs of elecraft that I
have built.

I contacted elecraft about this issue but I wanted to ask if others have
this problem too? What can I do?

73

Gerhard Schwanz
DH3FAW
mailto:[hidden email]
http://www.gs-personal.de


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Re: Bad KPA100 PCB?

GS-3
Don,

as allways - ? - you were right!

I increased the temp to 430deg C and here I go. (Didn't know my iron could
go beyond 400, I mostly use 300-330 without problem.) It still takes a bit
longer to solder but the hole fills smoothly.

Off the hook - the building can go on.

:-)

Regarding manual: I read the part with the needed iron but I understood the
high power is needed for power transistor installation and such... And since
everything else worked the way I did it before...

Thank you very much!


Gerhard Schwanz
DH3FAW
mailto:[hidden email]
http://www.gs-personal.de


----- Original Message -----
From: "W3FPR - Don Wilhelm" <[hidden email]>
To: "Gerhard Schwanz" <[hidden email]>; <[hidden email]>
Sent: Friday, January 28, 2005 3:40 PM
Subject: Re: [Elecraft] Bad KPA100 PCB?


> Gerhard,
>
> I have found the KPA100 is more difficult to solder than other Elecraft
> kits, but I believe it is bacause that  PC board uses thicker copper than
> the other kits and is especially noticable when soldering to a grounded
pad.
>
> I increase the temperature on my soldering station to 750 to 800 degrees
F.
> (400 to 430 degrees C.) and have no problem.  The KPA100 manual states
that

> a low wattage 800 degree F. soldering iron is required.
>
> Try increasing the temperature of your iron.  Judging by your photo, I can
> definitely state that your iron is not hot enough, and the pads that give
> you the most trouble are the ground points.
>
> 73,
> Don W3FPR
>
> ----- Original Message -----
>
> I am just in the process of building my KPA100. And I discover more and
more
> solder points on the PCB where the solder is not accepted. Scraping the
pads
> a bit helps a bit but I don't think this is a solution.
>
> Some details. I don't know where in the process it started but right now
I'm
> on page 15 soldering the capacitors. And it's nearly every third hole that
> doesn't work. The solder sticks to the leads or the iron.
>
> I use the same iron and solder as with the other 10 PCBs of elecraft that
I

> have built.
>
> I contacted elecraft about this issue but I wanted to ask if others have
> this problem too? What can I do?
>
> 73
>
> Gerhard Schwanz
> DH3FAW
> mailto:[hidden email]
> http://www.gs-personal.de
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>


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Re: Bad KPA100 PCB?

Don Wilhelm-3
Gerhard,

I have a secret - if I don't have a good answer, I try to keep my mouth shut
<G>

73,
Don W3FPR

----- Original Message -----

> Don,
>
> as allways - ? - you were right!
>


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Re: Bad KPA100 PCB?

Timothy A. Raymer
In reply to this post by GS-3
Gerhard,

The other thing that will help is using the Biggest tip that will do a job
for you.  If you tip has more mass, it will tend to have less temperature
drop as you solder those components.  I did my mine with a 700F (370C) tip,
but I used the biggest one for a given job.

Glad you found a resolution to your problem.

Tim Raymer

At 08:55 01/28/2005, Gerhard Schwanz wrote:

>I increased the temp to 430deg C and here I go.Off the hook - the building
>can go on.

Timothy A. Raymer
Missouri Department of Health
and Senior Services

<traymer[at]mail.state.mo.us>                        <RaymeT[at]dhss.mo.gov>
<KA0OUV[at]arrl.net>

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RE: Bad KPA100 PCB?

Ron D'Eau Claire-2
In reply to this post by GS-3
Gerhard wrote:
I mostly use 300-330 without problem.) It still takes a bit longer to solder
but the hole fills smoothly.

-----------------------
Gerhard, using too low of a temperature is more likely to harm delicate
components than using a higher temperature.

You do not want to hold an iron on the joint too long, even at 300C. It
should be hot enough for the solder to flow within 2 or 3 seconds at the
most. So cranking up the temperature close to 400C and getting the solder to
flow quickly is easier on most parts - especially the I.C.s, transistors and
diodes.

I normally work at 375C (700F).

That brings up another point for anyone using de-soldering braid. In that
case 375C (700F) is not hot enough. The braid will pull too much heat away
from the joint, meaning the joint has to "cook" for a long time to melt the
solder. Like most of us, I prefer a solder sucker type of tool,  but when I
choose braid, I find no problem getting it to work with the iron at 425C
(800F). "Cooking" a joint with a cooler iron will more likely debond the
trace from the board!

Ron AC7AC


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Re: Bad KPA100 PCB?

Don Wilhelm-3
Ron's points should be well taken by everyone.  It takes 2 things together
to cook components and PC board traces - temperature and time, and actually
the time factor is more critical than the temperature.  If solder does not
flow in 2 to 3 seconds, turn up the heat or use an iron with a larger tip
(more heat mass).  Modern components usually are speced to withstand
soldering temperatures for 5 to10 seconds, so you are more likely to cause
damage from the time element than with a high temperature.  Keep those
soldering irons between 700F (375C) and 800F (426C).

PS - when the surface to be soldered is large (as on the KPA100 output
transistors and transformers), use a large iron tip, a small tip will have
the heat 'sucked out of it' by the large metal area on the PC board, and you
will have to dwell on the joint a long time waiting for the iron (and PC
board copper) to come up to temperature.

73,
Don W3FPR

----- Original Message -----

You do not want to hold an iron on the joint too long, even at 300C. It
should be hot enough for the solder to flow within 2 or 3 seconds at the
most. So cranking up the temperature close to 400C and getting the solder to
flow quickly is easier on most parts - especially the I.C.s, transistors and
diodes.

I normally work at 375C (700F).

That brings up another point for anyone using de-soldering braid. In that
case 375C (700F) is not hot enough. The braid will pull too much heat away
from the joint, meaning the joint has to "cook" for a long time to melt the
solder. Like most of us, I prefer a solder sucker type of tool,  but when I
choose braid, I find no problem getting it to work with the iron at 425C
(800F). "Cooking" a joint with a cooler iron will more likely debond the
trace from the board!



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RE: Bad KPA100 PCB?

srife
In reply to this post by Don Wilhelm-3
        No wonder! I thought it was my iron, or solder. I had similar
results but everything soldered ok eventually. I was running my iron at 725
degrees F. I missed that part in the manual. That's what I get for being in
a hurry to get started. I'll go back and find that in the manual. Makes
sense that it would be thicker though, since the KPA100 board has to deal
with a lot more heat than the K2 RF board.

Stan Rife
W5EWA
Houston, TX
K2 S/N 4216
 
-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of W3FPR - Don Wilhelm
Sent: Friday, January 28, 2005 8:41 AM
To: Gerhard Schwanz; [hidden email]
Subject: Re: [Elecraft] Bad KPA100 PCB?

Gerhard,

I have found the KPA100 is more difficult to solder than other Elecraft
kits, but I believe it is bacause that  PC board uses thicker copper than
the other kits and is especially noticable when soldering to a grounded pad.

I increase the temperature on my soldering station to 750 to 800 degrees F.
(400 to 430 degrees C.) and have no problem.  The KPA100 manual states that
a low wattage 800 degree F. soldering iron is required.

Try increasing the temperature of your iron.  Judging by your photo, I can
definitely state that your iron is not hot enough, and the pads that give
you the most trouble are the ground points.

73,
Don W3FPR

----- Original Message -----

I am just in the process of building my KPA100. And I discover more and more
solder points on the PCB where the solder is not accepted. Scraping the pads
a bit helps a bit but I don't think this is a solution.

Some details. I don't know where in the process it started but right now I'm
on page 15 soldering the capacitors. And it's nearly every third hole that
doesn't work. The solder sticks to the leads or the iron.

I use the same iron and solder as with the other 10 PCBs of elecraft that I
have built.

I contacted elecraft about this issue but I wanted to ask if others have
this problem too? What can I do?

73

Gerhard Schwanz
DH3FAW
mailto:[hidden email]
http://www.gs-personal.de


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RE: Bad KPA100 PCB?

Brian Mury-3
> The KPA100 manual states that a low wattage 800 degree F. soldering
iron is
> required.

No - it says that a temperature-controlled iron at 700 to 800 degree tip
is required.

It also states that a larger iron or soldering gun is required for the
power transistors, output transformer and DC power wiring, and that a
low-wattage iron *cannot* be used for these steps.

I built the KPA100 with a small tip at 700 degrees with no problem. I
did use a large tip for the power transistors, etc, but still at 700
degrees. I had no problems at all.


On Fri, 2005-28-01 at 18:03 -0600, Stan Rife wrote:
> No wonder! I thought it was my iron, or solder. I had similar
> results but everything soldered ok eventually. I was running my iron at 725
> degrees F. I missed that part in the manual.

725 degrees should work fine.


--
73, Brian
VE7NGR

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