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KPA500 Z Bracket & Top Cover

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Chuck - AE4CW

KPA500 Z Bracket & Top Cover

Just finished a KPA500 build and all went smoothly. The only issue I see is that the Z-Bracket appears to be about 1mm taller at the front than at the rear. The result is that the top cover protrudes above the front panel in the center by a small amount, perhaps 1mm. At the rear the top cover is flush with the rear panel in the center...no protrusion at all. This is a cosmetic issue but does detract a bit for the "fit and finish" of the rest of the KPA500 and the K3.

Has anyone else seen this issue? Thought I would ask before calling home.
---
Chuck, AE4CW

---
Chuck, AE4CW

Iain MacDonnell - N6ML-2

Re: KPA500 Z Bracket & Top Cover

On Fri, Feb 10, 2012 at 6:54 PM, Chuck - AE4CW <[hidden email]> wrote:
> Just finished a KPA500 build and all went smoothly. The only issue I see is
> that the Z-Bracket appears to be about 1mm taller at the front than at the
> rear. The result is that the top cover protrudes above the front panel in
> the center by a small amount, perhaps 1mm. At the rear the top cover is
> flush with the rear panel in the center...no protrusion at all. This is a
> cosmetic issue but does detract a bit for the "fit and finish" of the rest
> of the KPA500 and the K3.
>
> Has anyone else seen this issue? Thought I would ask before calling home.

Yes, I have exactly the same issue, but I don't have a solution. It
hasn't bothered me enough to pursue it with support, but I couldn't
see any way that it could have been caused by incorrect assembly, so
it must be a malformed Z-bracket.....

Let me know if you find a solution!

~iain / N6ML
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Roger Dallimore-2

Re: KPA500 Z Bracket & Top Cover

In reply to this post by Chuck - AE4CW

Hi Chuck,

Yes I have exactly the same issue with my KPA500.

73
Roger MW0IDX

On 11/02/2012 02:54, Chuck - AE4CW wrote:

> Just finished a KPA500 build and all went smoothly. The only issue I see is
> that the Z-Bracket appears to be about 1mm taller at the front than at the
> rear. The result is that the top cover protrudes above the front panel in
> the center by a small amount, perhaps 1mm. At the rear the top cover is
> flush with the rear panel in the center...no protrusion at all. This is a
> cosmetic issue but does detract a bit for the "fit and finish" of the rest
> of the KPA500 and the K3.
>
> Has anyone else seen this issue? Thought I would ask before calling home.
> ---
> Chuck, AE4CW
>
>

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K9TM

Re: KPA500 Z Bracket & Top Cover

In reply to this post by Iain MacDonnell - N6ML-2

I noticed this but didn't let it bother me. I just looked again and if I push down on the top cover, it goes down flush or a little below flush. I wouldn't say that the z-bracket is the problem (if there is a problem). I didn't take the top cover off to see how possible this is but my initial suggestion (if anything were to be done) would be to add another screw closer to the front panel or to move the existing hole forward closer to the front cover. At least on my unit, SN49, this would make it flush. This is not an issue on the rear because of the tab and screw that holds the tab down.

I guess someone may suggest some really really thin but really really sticky tape to hold this down without any screws but I wouldn't do that. If the case stuck up high enough that I could see inside the amp (under the cover), it would bother me but as is as long as it keeps putting out the appropriate amount of watts... I'm more than satisfied as is!

73, Tim K9TM, KP2TM

On Feb 10, 2012, at 10:55 PM, iain macdonnell - N6ML wrote:

On Fri, Feb 10, 2012 at 6:54 PM, Chuck - AE4CW <[hidden email]> wrote:
> Just finished a KPA500 build and all went smoothly. The only issue I see is
> that the Z-Bracket appears to be about 1mm taller at the front than at the
> rear. The result is that the top cover protrudes above the front panel in
> the center by a small amount, perhaps 1mm. At the rear the top cover is
> flush with the rear panel in the center...no protrusion at all. This is a
> cosmetic issue but does detract a bit for the "fit and finish" of the rest
> of the KPA500 and the K3.
>
> Has anyone else seen this issue? Thought I would ask before calling home.

Yes, I have exactly the same issue, but I don't have a solution. It
hasn't bothered me enough to pursue it with support, but I couldn't
see any way that it could have been caused by incorrect assembly, so
it must be a malformed Z-bracket.....

Let me know if you find a solution!

~iain / N6ML
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Iain MacDonnell - N6ML-2

Re: KPA500 Z Bracket & Top Cover

Tim,

That's not the same issue - top of my Z-bracket (at the front only) is
flush with the outside face of the top of the front panel, so the top
panel is pushed up by its own thickness, and cannot be pushed down.

~iain / N6ML

On Sat, Feb 11, 2012 at 8:04 AM, K9TM <[hidden email]> wrote:

>
> I noticed this but didn't let it bother me. I just looked again and if I push down on the top cover, it goes down flush or a little below flush. I wouldn't say that the z-bracket is the problem (if there is a problem). I didn't take the top cover off to see how possible this is but my initial suggestion (if anything were to be done) would be to add another screw closer to the front panel or to move the existing hole forward closer to the front cover. At least on my unit, SN49, this would make it flush. This is not an issue on the rear because of the tab and screw that holds the tab down.
>
> I guess someone may suggest some really really thin but really really sticky tape to hold this down without any screws but I wouldn't do that. If the case stuck up high enough that I could see inside the amp (under the cover), it would bother me but as is as long as it keeps putting out the appropriate amount of watts... I'm more than satisfied as is!
>
> 73, Tim K9TM, KP2TM
>
> On Feb 10, 2012, at 10:55 PM, iain macdonnell - N6ML wrote:
>
> On Fri, Feb 10, 2012 at 6:54 PM, Chuck - AE4CW <[hidden email]> wrote:
>> Just finished a KPA500 build and all went smoothly. The only issue I see is
>> that the Z-Bracket appears to be about 1mm taller at the front than at the
>> rear. The result is that the top cover protrudes above the front panel in
>> the center by a small amount, perhaps 1mm. At the rear the top cover is
>> flush with the rear panel in the center...no protrusion at all. This is a
>> cosmetic issue but does detract a bit for the "fit and finish" of the rest
>> of the KPA500 and the K3.
>>
>> Has anyone else seen this issue? Thought I would ask before calling home.
>
> Yes, I have exactly the same issue, but I don't have a solution. It
> hasn't bothered me enough to pursue it with support, but I couldn't
> see any way that it could have been caused by incorrect assembly, so
> it must be a malformed Z-bracket.....
>
> Let me know if you find a solution!
>
> ~iain / N6ML
> ______________________________________________________________
> 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
>

Roy Morris-6

Re: KPA500 Z Bracket & Top Cover

In reply to this post by Chuck - AE4CW

Mine bows up very slightly in the middle, but it is not objectionable. This
must be normal. Roy Morris W4WFB

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Chuck - AE4CW

Re: KPA500 Z Bracket & Top Cover

Well, here what I discovered that is causing or contributing to the top cover protrusion (at lease in my case):
1) My power transformer is not symmetrical. It is thicker on the z-bracket side and thinner on the left side. When the nut is tightened, the metal disk leans to the left causing the bolt to also lean to the left. The head of the bolt put a twisting moment on the bottom cover causing the left front corner to be bent slightly down. This then pulls the left side panel down which now causes the front panel to also droop slightly on the left side. Now all of this is a matter 20-30 thousands of an inch, so it's certainly not huge but enough to contribute to the protrusion.
2) The very top/front edge of the Z bracket protrudes several thousands of an inch above the folded over portion that contains the screw bosses. So, tightening the front/middle cover screw actually causes the front cover to be pushed up slightly at the edge. I think this is a manufacturing defect.

Here's what I've done so far.
1) After loosening the transformer I straightened the slight bend in the bottom cover by putting a shim under the left side panel and pressing down with a blunt tool on the bottom cover just in front of the transformer.
2) I put some plastic shims under the metal disk on the thinner side to allow the plate to remain level and the bolt perpendicular as the nut is tightened. There is still some distortion of the bottom cover when the nut is tightened to 55 in-lbs. I believe the extra plate on the bottom is intended to remedy this, but there is still some distortion.

After all this there is still some protrusion but about 1/2 as much as before...the total in the middle is about 30 thousands while the edges are about 10 thousands. So the middle is about 20 higher than it should be.

BTW, the z bracket by itself is not at fault (other than the slight defect at the top/front. It's actually about 8-10 thousands shorten in the front than the rear. So, bottom line, as best I can tell, the bottom cover distortion caused by tightening the transformer bolt is the main culprit. Once again, this is NOT a big deal but just not quite up the the "fit and finish" standard that Elecraft is well known for. I'll give the folks in CA a call next week to see what advice they have.
---
Chuck, AE4CW

---
Chuck, AE4CW

Bob Wolbert, K6XX

Re: KPA500 Z Bracket & Top Cover

In reply to this post by Chuck - AE4CW

Chuck,

Did you rotate the big transformer a little to get a better fit?

The toroid is wound with big wire, which overlaps. This creates the irregularities you see.
73 de Bob, K6XX

Chuck - AE4CW <[hidden email]> wrote:

>Well, here what I discovered that is causing or contributing to the top cover
>protrusion (at lease in my case):
>1) My power transformer is not symmetrical. It is thicker on the z-bracket
>side and thinner on the left side. When the nut is tightened, the metal
>disk leans to the left causing the bolt to also lean to the left. The head
>of the bolt put a twisting moment on the bottom cover causing the left front
>corner to be bent slightly down. This then pulls the left side panel down
>which now causes the front panel to also droop slightly on the left side.
>Now all of this is a matter 20-30 thousands of an inch, so it's certainly
>not huge but enough to contribute to the protrusion.
>2) The very top/front edge of the Z bracket protrudes several thousands of
>an inch above the folded over portion that contains the screw bosses. So,
>tightening the front/middle cover screw actually causes the front cover to
>be pushed up slightly at the edge. I think this is a manufacturing defect.
>
>Here's what I've done so far.
>1) After loosening the transformer I straightened the slight bend in the
>bottom cover by putting a shim under the left side panel and pressing down
>with a blunt tool on the bottom cover just in front of the transformer.
>2) I put some plastic shims under the metal disk on the thinner side to
>allow the plate to remain level and the bolt perpendicular as the nut is
>tightened. There is still some distortion of the bottom cover when the nut
>is tightened to 55 in-lbs. I believe the extra plate on the bottom is
>intended to remedy this, but there is still some distortion.
>
>After all this there is still some protrusion but about 1/2 as much as
>before...the total in the middle is about 30 thousands while the edges are
>about 10 thousands. So the middle is about 20 higher than it should be.
>
>BTW, the z bracket by itself is not at fault (other than the slight defect
>at the top/front. It's actually about 8-10 thousands shorten in the front
>than the rear. So, bottom line, as best I can tell, the bottom cover
>distortion caused by tightening the transformer bolt is the main culprit.
>Once again, this is NOT a big deal but just not quite up the the "fit and
>finish" standard that Elecraft is well known for. I'll give the folks in CA
>a call next week to see what advice they have.
>---
>Chuck, AE4CW
>
>--
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>Sent from the Elecraft mailing list archive at Nabble.com.
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