Interestingly enough, I just received KPA500 #594 and there is an errata
sheet with 1/4 4-40 screws attached.
John N1JM
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G'morning, all:
In case anyone is keeping score, I shortened the 5/16
screws that support the PA module on the Z bracket and the
Right Hand Panel, reinstalled them and now no longer have
thermal expansion clicks/ticks/pops of any kind as the amp
heats up(tested to 65C) or cools off. I had
I changed the screws in my amp yesterday morning and ran it yesterday
afternoon and night, and have not heard any pop since. I used the
3/16 that were extras from a K3 build. I got from the hardware store
4-40 1/2 long flat heads, but the counter-sink angle was different,
so I did not use them.
, 2011 16:59:34 GMT+00:00
Subject: Re: [Elecraft] KPA500 Heat Expansion Pop
I don't think there are any 1/4 4-40 flat head screws in the K3
(either) ... ? There are 1/4 pan heads, but flat heads are 3/16 or
5/16 (IIRC)
~iain / N6ML
On Mon, Dec 12, 2011 at 9:04 PM, n...@widomaker.com n
from my Verizon Wireless 4GLTE Phone
-Original message-
From: KD2A rvr...@verizon.net
To: elecraft@mailman.qth.net
Sent: Tue, Dec 13, 2011 03:27:34 GMT+00:00
Subject: Re: [Elecraft] KPA500 Heat Expansion Pop
My amp has been click free for four days now. To clarify, page 22 Fig.27
Are you still pop free after changing the screws? Are the five screws
you changed the ones installed on page 22 of the assembly manual?
Thanks,
Joe N9VX
--
I think I may have
My amp has been click free for four days now. To clarify, page 22 Fig.27,
is the area I'm referring to. Change the five 5/16 screws to 3/16 when
mounting the Z-bracket on the PA/LPF module. I also would have preferred to
use 1/4 screws but none come with the kit.
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How about spares from the K3 kit?
...bc. nr4c
Sent from my Verizon Wireless 4GLTE Phone
-Original message-
From: KD2A rvr...@verizon.net
To: elecraft@mailman.qth.net
Sent: Tue, Dec 13, 2011 03:27:34 GMT+00:00
Subject: Re: [Elecraft] KPA500 Heat Expansion Pop
My amp has been click free
Message: 40
Date: Sat, 10 Dec 2011 19:35:16 -0500
From: Don Wilhelm w3...@embarqmail.com
Subject: Re: [Elecraft] KPA500 Heat Expansion Pop
To: elecraft@mailman.qth.net
Message-ID: 4ee3fac4.1080...@embarqmail.com
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I would be concerned
Could we get more info on this possible fix, how much disassembly is
required? Looks like the PA unit must come out?
Joe N9VX
--
I think I may have solved this problem. One of the
I would be concerned that going from 5/16 inch to 3/16 inch may be too
much of a difference to assure that the screws have enough thread
engagement. I would think going to 1/4 inch would be a better choice.
This sounds like a simple problem, and the real cause is that the holes
were not
I just built #570 last week and was concerned with how 'wobbly' the bracket
was with the 5/16 screws not wanting to over-tighten the screws. But
knowing it should not be that wobbly, I gave a little more torque while
pressing down and they all fully tightened down nicely.
73, Mitch
--
View
I think I may have solved this problem. One of the other posts mentions that
the Z-bracket screws are too long and you don't get a tight fit. I changed
the five screws from 5/16 to 3/16 and did notice a better grip between the
bracket and the PA assembly. I have run it all evening and haven't
The Z bracket should be secure and tight against the side of the heat sink.
My KPA500 has 5/16 screws and they tighten the Z-bracket so it does not
move. More recently there have been comments that the 5/16 screws are too
long, and the length of those screws has now been reduced to 1/4 to ensure
Every engineering new grad wants to be the Design Engineer, never
knowing how complex and demanding Product Engineering can be. Nearly 50
email list posts leads to 1/16 change in screw length. I'd be amazed
and stunned, except I've seen it so many times. Count up all the parts
in your
This is what I know at this point. Based on comments on this board and
private emails, this is a common issue, I would think a good many
people that don't think they have the issue just don't hear it due to
hearing loss or head phone use. It happens with both factory made and
kits.
I tried to
My KPA500 has developed a heat expansion pop. When it heats up and
then cools down I get a pop from inside the amp. It does this now
every time I make a SSB transmission.
Anyone else experience this? If so, any resolution?
Joe N9VX
__
I've not heard it.
What gets warm during a transmission is, of course, the RF module heat sink.
The RF module is supported by screws into the heat sink on both sides - one
side going into an aluminum Z bracket that runs down the center of the
KPA500 and the other side is secured to the right
While you're inside the amp, make sure that the transformer is secure and
snug (tighten the bolts if needed, reset the washer and retighten). The
pitch of the pop may be a clue as to what is happening (big thump/tiny pop;
deep/high pitched etc.).
The transformer and amp module are the only two
Heat Expansion Pop
My KPA500 has developed a heat expansion pop. When it heats up and then
cools down I get a pop from inside the amp. It does this now every time I
make a SSB transmission.
Anyone else experience this? If so, any resolution?
Joe N9VX
Gary,
That sounds like what I am hearing, thought it was a relay controlling
the fan, but as you said, it did not pop when the fan came on/off.
Joe N9VX
-
Mine pops or clicks too.
In my
:40 a.m.
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA500 Heat Expansion Pop
Gary,
That sounds like what I am hearing, thought it was a relay controlling the
fan,
but as you said, it did not pop when the fan came on/off.
Joe N9VX
- Original Message -
From: Joe Word joe.n...@gmail.com
To: elecraft@mailman.qth.net
Sent: Thursday, December 08, 2011 11:37 AM
Subject: [Elecraft] KPA500 Heat Expansion Pop
My KPA500 has developed a heat expansion pop. When it heats up and
then cools down I get a pop from inside the amp
or
something that is normal. The pops are very frequent regardless of mode.
Otherwise, the amp appears to function normally.
Dave, N4QS
- Original Message -
From: Joe Wordjoe.n...@gmail.com
To:elecraft@mailman.qth.net
Sent: Thursday, December 08, 2011 11:37 AM
Subject: [Elecraft] KPA500 Heat
Happens here a lot . Amp doesn't have to warm up much. This symptom also
didn't exist when the amp was new but started during long use in contest
weekend
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Sent from the Elecraft
All,
I don't have the noise you describe, but it's logical to me that if the bolt
that goes through the center of the transformer has any slack in it, it might
cause a click or thump when cooling or heating. That may be why Elecraft used
the bell washer under the bolt head to allow expansion
Message-
From: elecraft-boun...@mailman.qth.net [mailto:elecraft-
boun...@mailman.qth.net] On Behalf Of Joe Word
Sent: Friday, 9 December 2011 10:40 a.m.
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA500 Heat Expansion Pop
Gary,
That sounds like what I am hearing, thought
@mailman.qth.net
Sent: Thursday, December 08, 2011 11:37 AM
Subject: [Elecraft] KPA500 Heat Expansion Pop
My KPA500 has developed a heat expansion pop. When it heats up and
then cools down I get a pop from inside the amp. It does this now
every time I make a SSB transmission.
Anyone else experience
:37 AM
Subject: [Elecraft] KPA500 Heat Expansion Pop
My KPA500 has developed a heat expansion pop. When it heats up and
then cools down I get a pop from inside the amp. It does this now
every time I make a SSB transmission.
Anyone else experience this? If so, any resolution?
Joe N9VX
Those having problems with KPA 500 popping have you tried setting the fan to
speed 3 on the amp? This speed is not very noisy at all and may prevent the
popping.
Toby W4CAK
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Elecraft mailing list
Home:
OK.Try setting the fan speed to a setting of 1 or perhaps 2. Three may be
a bit noisy for some.
Toby W4CAK
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Help: http://mailman.qth.net/mmfaq.htm
, December 09, 2011 2:53 PM
Subject: [Elecraft] KPA500 Heat Expansion Pop
OK.Try setting the fan speed to a setting of 1 or perhaps 2. Three may
be a bit noisy for some.
Toby W4CAK
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