KPA-500 no RF until power cycle

[Roger Dallimore-2]

This came up a while back but I haven't seen any answers yet.

When going into "operate" there is no power output, no lights (asterisk OK).
Switching the power button off then on again and placing it into
"operate,"  it works fine..Happens every time.

Any clues on how to fix this will be gratefully received. I'm very
pleased with the amp, just this little niggle I want to sort out.

73
Roger MW0IDX

K3 #191
KPA-500 #268
K2 #2724
KX1 #416



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[NH7RO]

I have the same problem with mine, too (SN#0250).

What I do is switch back and forth between a couple of bands with the band buttons and then it's fine.

I made it into a habit whenever I turn the amp on so I can QRV as soon as I want to and not have to fiddle with it when trying to snag a DX station.

I suspect sticky relays;  wish there was a good and easy fix for this annoyance!

73,  Jeff  NH7RO

[Geoffrey Downs-3]

A similar phenomenon here but not every time. Typically it happens when the
amp is cold (eg having been off overnight) the rear power switch is off and
I switch it on, followed by the front ON switch, then go to Operate. As with
Roger, cycling the front power switch clears it. No key cable by the way,
just the the AUX cable.

73 to all

Geoff
G3UCK

-----Original Message-----
From: Roger Dallimore
Sent: Monday, November 21, 2011 7:52 PM

When going into "operate" there is no power output, no lights (asterisk OK).
Switching the power button off then on again and placing it into
"operate,"  it works fine..Happens every time.


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[Jack Brindle-2]

Guys;

This problem is typically caused by the K3's TX INH input being enabled. Be sure that the Config:TX INH menu setting is set to OFF.
I emphasize, this is a K3 setting, not KPA500.

Jack Brindle, W6FB


On Nov 25, 2011, at 4:55 AM, Geoffrey Downs wrote:

> A similar phenomenon here but not every time. Typically it happens when the
> amp is cold (eg having been off overnight) the rear power switch is off and
> I switch it on, followed by the front ON switch, then go to Operate. As with
> Roger, cycling the front power switch clears it. No key cable by the way,
> just the the AUX cable.
>
> 73 to all
>
> Geoff
> G3UCK
>
> -----Original Message-----
> From: Roger Dallimore
> Sent: Monday, November 21, 2011 7:52 PM
>
> When going into "operate" there is no power output, no lights (asterisk OK).
> Switching the power button off then on again and placing it into
> "operate,"  it works fine..Happens every time.
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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[Geoffrey Downs-3]

Thanks for the suggestion Jack but TX INH is set to OFF here.

No doubt the solution will be simple but I haven't found it yet.

73 to all.

Geoff
G3UCK
K3 #266


-----Original Message-----
From: Jack Brindle
Sent: Friday, November 25, 2011 1:59 PM

This problem is typically caused by the K3's TX INH input being enabled. Be
sure that the Config:TX INH menu setting is set to OFF.
I emphasize, this is a K3 setting, not KPA500.

Jack Brindle, W6FB



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[Roy Morris-6]

Hi Jack,
Thanks for the info, but TX INH was also off in my K3 as well.  Something
else appears to be causing this.  Thanks again.  Roy  W4WFB

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[Mike Harris]

I don't have a KPA500, however, I did have an occasional problem with
the K3 on power up.  If I pressed the K3 power switch too quickly after
switching on the PSU (switch mode) sometimes the K3 would lock up part
powered.  If I delay pressing the power switch for 3-4 seconds all is
OK.  Possibly this is caused by the K3 having to settle to an idle off
state, sort of wake up before requesting full switch on.  Power rails
caps charged, that sort of thing.

The KPA500 might be the same.

Regards,

Mike VP8NO

On 25/11/2011 11:28, Geoffrey Downs wrote:

> Thanks for the suggestion Jack but TX INH is set to OFF here.
>
> No doubt the solution will be simple but I haven't found it yet.
>
> 73 to all.
>
> Geoff
> G3UCK
> K3 #266
>
>
> -----Original Message-----
> From: Jack Brindle
> Sent: Friday, November 25, 2011 1:59 PM
>
> This problem is typically caused by the K3's TX INH input being enabled. Be
> sure that the Config:TX INH menu setting is set to OFF.
> I emphasize, this is a K3 setting, not KPA500.
>
> Jack Brindle, W6FB

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[NH7RO]

I think I found the culprit thanks to the mention of "no key cable connected when using the KPA-K3 AUX cable."  (I already checked the TX:INH" item and it was OFF)

I had my key cable connected to both the K3 and KPA despite also having the AUX cable between the two.
I had left it connected ever since I was initially having trouble with the amp right after I built it---that trouble was due to one of the ribbon connectors only being connected to one row of pins which I soon fixed.
Thereafter, I forgot about having the key cable still in play.

This morning I unplugged the key cable and turned on the KPA, hit the mic button and voila!  The amp powers up 1st time on every band as it should!  Aha!

Hope this helps others who might be experiencing the same problem---it's not sticky relays in the amp it's sticky relays in my noggin!

73,  Jeff,  NH7RO

[Roy Morris-6]

Roger, MW0IDX
Do you have the KEY Cable and the KPA3AUX cable BOTH connected between your
K3 and KPA500?  Jeoff, G3UCK is using the KPA3AUX cable only.  As I
understand it, on occasion he is still having no KPA500 RF until power is
recycled.   I am trying to find out if eliminating the KEY Cable when using
the KPAK3AUX cable is supposed to cure this problem.  Meanwhile, I am
removing the KEY Cable from my K Line.  Roy Morris  W4WFB

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[k6dgw]

FWIW:  I use the heavy cable between the K3 AUX and KPA500 DB15 and
nothing else.  It always makes RF.  I haven't shut the back panel power
switch off since I first turned it on, however.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 11/25/2011 11:59 AM, Roy Morris wrote:
> Roger, MW0IDX
> Do you have the KEY Cable and the KPA3AUX cable BOTH connected between your
> K3 and KPA500?  Jeoff, G3UCK is using the KPA3AUX cable only.
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