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K3 Power Shutdown

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Hunsdon Cary III

K3 Power Shutdown

I've used an Astron RS-35M power supply for about 25 years, that's what I used when I got my K3-100 #3449. A few weeks ago, the K3 began to shut down in transmit....25 watts seemed to be the magic number...below 25 watts, OK; above 25, dial lights flicker (no error message or High Current warning) and the K3 shuts down. It will turn back on immediately but the same thing happens.
High SWR?...no, showing 1.1-1....antenna connected? YES, it does the same thing with my tri-bander, dipole, and dummy load! Not the antenna or feedline.
Must be the power supply, right? Well, I ordered a Samlux SEC 1223 which arrived UPS today and that's not the problem....K3 still shuts down!

Have I done anything to the K3....well, as a matter of fact, I used some of my VHSL basketball officiating money to add the Digital Voice Recorder. No easy feat installing that as the front panel has to come off but, hey, I "built it", I can do it... and did...complete with anti-static mat, etc. DVR works so I did something right or maybe not....

My Icom 706MkIIG works fine with the SEC 1223 and all the antennas, including dummy load. Alas, the problem must be inside my K3...Absent error messages, plus nothing in the manual under troubleshooting that covers it, I'd appreciate some help in tracking this problem down and resolving it!

73,
"H", K4TM
LYNCHBURG, VA

H. Cary III
[hidden email]

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w7go

Re: K3 Power Shutdown

Same thing happened here with that power supply and K3/100.
Couldn't keep the K3 from tripping starting at about 50 watts.
Now using the Astron SS-30 with no problems.

73,

Tony W7GO

On 3/23/2011 5:40 PM, Hunsdon Cary III wrote:

> I've used an Astron RS-35M power supply for about 25 years, that's what I used when I got my K3-100 #3449. A few weeks ago, the K3 began to shut down in transmit.
> 73,
> "H", K4TM
> LYNCHBURG, VA
>
>
> H. Cary III
> [hidden email]
>
>
>
>
>

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Don Wilhelm-4

Re: K3 Power Shutdown

In reply to this post by Hunsdon Cary III

"H",

Have you done the TX Gain Calibration lately? If not, that may be a
first step. Beyond that, I can only guess, and given the information
that I have, that guess may be wrong.

73,
Don W3FPR

On 3/23/2011 8:40 PM, Hunsdon Cary III wrote:

> I've used an Astron RS-35M power supply for about 25 years, that's what I used when I got my K3-100 #3449. A few weeks ago, the K3 began to shut down in transmit....25 watts seemed to be the magic number...below 25 watts, OK; above 25, dial lights flicker (no error message or High Current warning) and the K3 shuts down. It will turn back on immediately but the same thing happens.
> High SWR?...no, showing 1.1-1....antenna connected? YES, it does the same thing with my tri-bander, dipole, and dummy load! Not the antenna or feedline.
> Must be the power supply, right? Well, I ordered a Samlux SEC 1223 which arrived UPS today and that's not the problem....K3 still shuts down!
>
> Have I done anything to the K3....well, as a matter of fact, I used some of my VHSL basketball officiating money to add the Digital Voice Recorder. No easy feat installing that as the front panel has to come off but, hey, I "built it", I can do it... and did...complete with anti-static mat, etc. DVR works so I did something right or maybe not....
>
> My Icom 706MkIIG works fine with the SEC 1223 and all the antennas, including dummy load. Alas, the problem must be inside my K3...Absent error messages, plus nothing in the manual under troubleshooting that covers it, I'd appreciate some help in tracking this problem down and resolving it!
>
> 73,
> "H", K4TM
> LYNCHBURG, VA
>
>
> H. Cary III
> [hidden email]
>
>
>
> ______________________________________________________________
> 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
>

DaveL G3TJP

Re: K3 Power Shutdown

In reply to this post by Hunsdon Cary III

Howdy, "H."

Have you checked what your PSU is doing when you try to tx at more than 25W?

Cycle round the options available by poking the "DISP" "METER" button and find the one that monitors your voltage input (it will be about 0.3v below your PSU voltage because of a protection diode). Watch what happens to that voltage as you sneak up towards 25W. If the voltage is showing a progressive drop, then you either have a sick PSU or there's a problem in the feed cable. It's usually connections or an inline fuse where conductivity problems arise.

Did you fit your own Andersons on the cable? Did you solder and if you did, was the solder wicked inside the contact's barrel? Did the contacts click home in the shells with a most definite click? Once they've clicked into place they are very firmly there. I think you have to experience trouble with an "un-clicked" Anderson before you really appreciate that click HI!

Hope that helps, or at least keeps you busy for a while HI!

Very best wishes and hope your problem is easily overcome.

73 Dave G3TJP
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Joe Subich, W4TV-4

Re: K3 Power Shutdown

> Have you checked what your PSU is doing when you try to tx at more
> than 25W?

Check the Astron supply carefully. The RS-35 is a linear supply and
it is susceptible to failure of one/more of the pass transistors over
time, failure of one/more of the rectifier diodes, aging of the current
sensing resistor with time or even simple loosening of the screws on
the capacitor. Any of the age related issues could leave the RS-35
unable to provide more than 5A which would cause the K3 to shut down
at about 25 Watts output.

73,

... Joe, W4TV

On 3/23/2011 9:13 PM, David Lankshear wrote:

> Howdy, "H."
>
> Have you checked what your PSU is doing when you try to tx at more than 25W?
>
> Cycle round the options available by poking the "DISP" "METER" button and find the one that monitors your voltage input (it will be about 0.3v below your PSU voltage because of a protection diode). Watch what happens to that voltage as you sneak up towards 25W. If the voltage is showing a progressive drop, then you either have a sick PSU or there's a problem in the feed cable. It's usually connections or an inline fuse where conductivity problems arise.
>
> Did you fit your own Andersons on the cable? Did you solder and if you did, was the solder wicked inside the contact's barrel? Did the contacts click home in the shells with a most definite click? Once they've clicked into place they are very firmly there. I think you have to experience trouble with an "un-clicked" Anderson before you really appreciate that click HI!
>
> Hope that helps, or at least keeps you busy for a while HI!
>
> Very best wishes and hope your problem is easily overcome.
>
> 73 Dave G3TJP
> ______________________________________________________________
> 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
>