KPA500 fault at H44KW (no pwr high SWR)

[Neil G0JHC]

I wonder if anyone on this reflector could offer  advice to the current
H44KW DXpedition.  They have 2 new  KPA500's with them. One has gone down
the first day. The fault is "The linear is not putting any power out what so
ever. The SWR is very high when you switch the amp from Standby to Operate.
Everything else is working such as the LEDs etc."

 

I am calling them back in a few hours with (hopefully) a few things to
check.

 

Their tool list is, a screw driver to open it up and a test meter.

 

Where do they want to start in the simple fault diagnostic process please.
They would only want to spend an hour or two to determine if it is fixable
there or needs to be packed for a fix once home. I.e. they can trace a
signal path/dry joint, and compare with the 2nd unit, but haven't access to
replacement parts.

 

Thanks for any help next 24 hrs.

 

Neil G0JHC

 

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[David Shoaf]

Neil,

Please contact Elecraft Customer Support at K3support 'at' elecraft.com.  We can help out the DXpedition assessment efforts and help determine possible remedy options.

Cheers,

David/KG6IRW
Elecraft Customer Support

[Robert Friess]

Check the wires between the ANTENNA connector and the low pass filter board.

Bob, N6CM

On Wed, Feb 20, 2013 at 8:08 AM, David Shoaf <[hidden email]>wrote:

> Neil,
>
> Please contact Elecraft Customer Support at K3support 'at' elecraft.com.
>  We
> can help out the DXpedition assessment efforts and help determine possible
> remedy options.
>
> Cheers,
>
> David/KG6IRW
> Elecraft Customer Support
>
>
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/KPA500-fault-at-H44KW-no-pwr-high-SWR-tp7570161p7570164.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
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[Oliver Dröse]

 
Hi Neil,
 
let them check if the connection wires between PA board and output connector are still in place! I had that failure once, too. The plugin-connection is not as strong as it could be ...
 
73, Olli - DH8BQA
 
 

> Neil G0JHC <[hidden email]> hat am 20. Februar 2013 um 16:05 geschrieben:
>
>
> I wonder if anyone on this reflector could offer advice to the current
> H44KW DXpedition. They have 2 new KPA500's with them. One has gone down
> the first day. The fault is "The linear is not putting any power out what so
> ever. The SWR is very high when you switch the amp from Standby to Operate.
> Everything else is working such as the LEDs etc."
>
>
>
> I am calling them back in a few hours with (hopefully) a few things to
> check.
>
>
>
> Their tool list is, a screw driver to open it up and a test meter.
>
>
>
> Where do they want to start in the simple fault diagnostic process please.
> They would only want to spend an hour or two to determine if it is fixable
> there or needs to be packed for a fix once home. I.e. they can trace a
> signal path/dry joint, and compare with the 2nd unit, but haven't access to
> replacement parts.
>
>
>
> Thanks for any help next 24 hrs.
>
>
>
> Neil G0JHC
>
>
>
> ______________________________________________________________
> 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

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[wa9fvp]

Here's a funny story.  Last week I ordered a KPA500.  Two days later a nearby Ham dropped off his KPA500 that failed.  His K3 was showing high SWR with no power.  He purchased his a year ago and didn't want to pay the expense of shipping it back to the factory.

I found a defective Q5 (see the TR switch schematic) on the Filter board.  Q5, an IPA50R399P is a 550v MOS Power Transistor.  My question is;  Q4 a similar device (an IRFSL9N60A) with almost identical specifications except it's a 600V, MOS transistor.  Can I use it as a replacement for an IPA50R399P?

Jack WA9FVP
Willco Electronics

[wayne burdick]

Sure, as long as the pinouts are the same, and the voltage and current ratings meet your switching requirements.

73,
Wayne
N6KR

On Nov 1, 2014, at 9:16 PM, wa9fvp <[hidden email]> wrote:

> Here's a funny story.  Last week I ordered a KPA500.  Two days later a nearby
> Ham dropped off his KPA500 that failed.  His K3 was showing high SWR with no
> power.  He purchased his a year ago and didn't want to pay the expense of
> shipping it back to the factory.
>
> I found a defective Q5 (see the TR switch schematic) on the Filter board.
> Q5, an IPA50R399P is a 550v MOS Power Transistor.  My question is;  Q4 a
> similar device (an IRFSL9N60A) with almost identical specifications except
> it's a 600V, MOS transistor.  Can I use it as a replacement for an
> IPA50R399P?
>
> Jack WA9FVP
> Willco Electronics
>
>
>
> -----
> Jack WA9FVP
>
> Sent from my TRS-80 :-)
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-fault-at-H44KW-no-pwr-high-SWR-tp7570161p7594358.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> 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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[Fred Townsend-2]

Not to contradict the expert but in addition to the specified parameters I
would want to know the on resistance (Ron) and the gate threshold voltages
were the same before I would sub.
73
Fred, AE6QL

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Wayne
Burdick
Sent: Saturday, November 01, 2014 9:54 PM
To: wa9fvp
Cc: [hidden email]
Subject: Re: [Elecraft] KPA500 fault at H44KW (no pwr high SWR)

Sure, as long as the pinouts are the same, and the voltage and current
ratings meet your switching requirements.

73,
Wayne
N6KR

On Nov 1, 2014, at 9:16 PM, wa9fvp <[hidden email]> wrote:

> Here's a funny story.  Last week I ordered a KPA500.  Two days later a
> nearby Ham dropped off his KPA500 that failed.  His K3 was showing
> high SWR with no power.  He purchased his a year ago and didn't want
> to pay the expense of shipping it back to the factory.
>
> I found a defective Q5 (see the TR switch schematic) on the Filter board.
> Q5, an IPA50R399P is a 550v MOS Power Transistor.  My question is;  Q4
> a similar device (an IRFSL9N60A) with almost identical specifications
> except it's a 600V, MOS transistor.  Can I use it as a replacement for
> an IPA50R399P?
>
> Jack WA9FVP
> Willco Electronics
>
>
>
> -----
> Jack WA9FVP
>
> Sent from my TRS-80 :-)
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/KPA500-fault-at-H44KW-no-pwr-high
> -SWR-tp7570161p7594358.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 Message delivered to
> [hidden email]

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[wa9fvp]

Hi fred,

The parameter is Rds(on),max  The IRFSL9N60A is .75 ohms at 9.2 amps and the IPA50R399CP is .399 ohms at 9 amps.  Q4 and Q5 are in series with a 100 ohm resistor and the diode so the difference in the R DS(on),max has little effect.

I forgot to mention that in manufacturing, it's always a good idea to have a second or even third manufacturer for parts.  If one parts manufacturer has a lead time that several months out, the second or third one can deliver ASAP.  That's probably why you'll see another part numbers in the same position.  

Jack WA9FVP
Willco Electronics

[wa9fvp]

I just found out that there's a Rework Kit E850607 for the KPA500.  It replaces Q5 (a FET)  with a Darlington Transistor.  The kit also includes a Zener Diode, resistors and capacitors and includes changes to the 12 meter LP filter.  The kit applies to board REV D9 or earlier.