Elecraft › [QRO]

KPA500 Heat Expansion Pop

Classic

List

Threaded

9 messages Options

Joe Word

KPA500 Heat Expansion Pop

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 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 heard a
click or a pop. I even ran the temp up and still nothing. Will it last? I
don't know, but it seems to have fixed it. The guy who suggested this has
submitted it to Elecraft for a change. Good luck and lets hear if any of you
have the same result.
______________________________________________________________
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

Don Wilhelm-4

Re: KPA500 Heat Expansion Pop

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 tapped deep enough, or that the tap had become worn at and was
not noticed in time - so several assemblies slipped through with
inadequately tapped holes. This may be a problem for a few, and not a
universal problem.

Yes, the easiest disassembly is to remove the PA unit. Not a major
chore, but yes, it is not trivial to get to those screws.

Don W3FPR

On 12/10/2011 6:35 PM, Joe Word wrote:

> 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 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 heard a
> click or a pop. I even ran the temp up and still nothing. Will it last? I
> don't know, but it seems to have fixed it. The guy who suggested this has
> submitted it to Elecraft for a change. Good luck and lets hear if any of you
> have the same result.
>

______________________________________________________________
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

NW0M

Re: KPA500 Heat Expansion Pop

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

Robert Dorchuck W6VY

Re: KPA500 Heat Expansion Pop

In reply to this post by Joe Word

Message: 40
Date: Sat, 10 Dec 2011 19:35:16 -0500
From: Don Wilhelm <[hidden email]>
Subject: Re: [Elecraft] KPA500 Heat Expansion Pop
To: [hidden email]
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

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.
-------------------------------

I agree Don. But I was told by Gary at Elecraft to use the 3/16" screws. There were no 1/4" screws in my kit.

Bob W6VY

______________________________________________________________
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

Joe Word

Re: KPA500 Heat Expansion Pop

In reply to this post by Joe Word

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 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 heard a
> click or a pop. I even ran the temp up and still nothing. Will it last? I
> don't know, but it seems to have fixed it. The guy who suggested this has
> submitted it to Elecraft for a change. Good luck and lets hear if any of you
> have the same result.
______________________________________________________________
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

KD2A

Re: KPA500 Heat Expansion Pop

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.

Nr4c

Re: KPA500 Heat Expansion Pop

How about "spares" from the K3 kit?

...bc. nr4c

Sent from my Verizon Wireless 4GLTE Phone

-----Original message-----
From: KD2A <[hidden email]>
To: [hidden email]
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,
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.

--
View this message in context:
http://elecraft.365791.n2.nabble.com/KPA500-Heat-Expansion-Pop-tp7082519p7088
611.html
Sent from the Elecraft mailing list archive at Nabble.com.
______________________________________________________________
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

Iain MacDonnell - N6ML-2

Re: 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, [hidden email] <[hidden email]> wrote:

> How about "spares" from the K3 kit?
>
> ...bc. nr4c
>
> Sent from my Verizon Wireless 4GLTE Phone
>
> -----Original message-----
> From: KD2A <[hidden email]>
> To: [hidden email]
> 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,
> 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.
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/KPA500-Heat-Expansion-Pop-tp7082519p7088
> 611.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> 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

Nr4c

Re: KPA500 Heat Expansion Pop

Didn't realize the screws were "flat-heads". Sorry.

...bill nr4c

Sent from my Verizon Wireless 4GLTE Phone

-----Original message-----
From: iain macdonnell - N6ML <[hidden email]>
To: "[hidden email]" <[hidden email]>
Cc: KD2A <[hidden email]>, [hidden email]
Sent: Tue, Dec 13, 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, [hidden email] <[hidden email]>
wrote:

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.
>
> --
> View this message in context:
>
http://elecraft.365791.n2.nabble.com/KPA500-Heat-Expansion-Pop-tp7082519p7088

> 611.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> 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