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KPA 500 failure

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Jorge Mejia

KPA 500 failure

Hello list members

I just finished putting together a KPA 500 which seems to be having problems.
When I turn on and try to run the voltage test, the “HV” button does not respond …. the led’s bar graph indicate 100 W and I can’t turn it off from the front panel switch, I have to use the one on the back, neither can I hear the fan discharging the caps. when switched off from the back. Has any of the list members experienced this situation?
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W2RMS

Re: KPA 500 failure

I also just finished my new KPA500 build. Not 15 minutes ago.
I didn't realize that the Fuse block is empty. Good thing i decided to actually double-check it before applying mains power.
I figured they'd put the fuses in based on the power cable i ordered (US version, 115 V).
Also, that whole business of selecting the right TAP (yellow is the default).

But after doing these checks the amp turned on ok and is showing 72.9 V when tapping HV button.
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Slava (Sal) B, W2RMS
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On Jun 8, 2014, at 9:40 AM, Jorge Mejia <[hidden email]> wrote:

> Hello list members
>
> I just finished putting together a KPA 500 which seems to be having problems.
> When I turn on and try to run the voltage test, the “HV” button does not respond …. the led’s bar graph indicate 100 W and I can’t turn it off from the front panel switch, I have to use the one on the back, neither can I hear the fan discharging the caps. when switched off from the back. Has any of the list members experienced this situation?
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

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Help: http://mailman.qth.net/mmfaq.htm
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Nr4c

Re: KPA 500 failure

In reply to this post by Jorge Mejia

I'd start by checking ALL wire connections. Be sure you have fuse block connected properly for your input voltage and proper fuses are installed.

Call Elecraft first thing tomorrow for assistance.

Good luck!

Mine showed no high voltage at first. Found a shorted by-pass cap (tiny SMD type) on board near the high voltage socket and removed it. No problems since!

Sent from my iPhone
...nr4c. bill

> On Jun 8, 2014, at 9:40 AM, Jorge Mejia <[hidden email]> wrote:
>
> Hello list members
>
> I just finished putting together a KPA 500 which seems to be having problems.
> When I turn on and try to run the voltage test, the “HV” button does not respond …. the led’s bar graph indicate 100 W and I can’t turn it off from the front panel switch, I have to use the one on the back, neither can I hear the fan discharging the caps. when switched off from the back. Has any of the list members experienced this situation?
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

Jack Brindle-2

Re: KPA 500 failure

In reply to this post by Jorge Mejia

Jorge;

Check the ribbon cable connections going to the front panel. This sounds like one of those cables is not connected properly. The chief candidate is the 40-pin cable on the left side that goes from the Front panel board to the IO board.

You should deb able to get the KPA going. If we can’t get you going with it today, then be sure to contact tech support tomorrow.

Jack Brindle, W6FB
Elecraft Engineering

On Jun 8, 2014, at 6:40 AM, Jorge Mejia <[hidden email]> wrote: