[Elecraft] Powering on/off a KPA500. Was: Re: Elecraft Digest, Vol 266, Issue 17

[Jim Rhodes]

OK, the turn on macro is still not working, but the turn off macro is
working as a toggle.  Press pf key once amp powers up, press it again and
it powers down.  I guess I am good to go, but don't know why.

On Sat, Jun 27, 2026 at 8:50 PM Bob Wilson, N6TV <n6tv at arrl.net> wrote:

> No PC software is needed.  A K3, K4 or K4/0 macro can easily power a
> KPA500 or KP1500 ON and OFF via AUX connectors, once you replace the
> Elecraft AUX cables with something better.  The technique was first
> explained on page 21 of the K3 Remote Owner's Manual
> <https://ftp.elecraft.com/K3-Remote/Manuals%20Downloads/K3%20Remote%20Owner's%20Manual%20%20Rev%20D.pdf>,
> and was implemented in the Y-BOX v2.1 and later, so you don't need to
> modify any cables.  Note that the macro documented in the K3 Remote manual
> has a major typo -- it omits the trailing semicolon.  That semicolon is
> *mandatory*, and it could cause the behavior that Jim and Joe are seeing.
>
> K0XU has one of my Y-BOXs that was prewired to connect K3 AUX Pin 11 to
> KPA500 AUX1 Pin 8 via straight Amphenol® 15-pin cables (unmodified Elecraft
> AUX cables will NOT work if they are anywhere in the chain from K3 to
> KAT500 to KPA500).  A block diagram was supplied with the Y-BOX explaining
> how to code the macro and how to connect all the cables.
>
> It's also explained here:
> https://www.kkn.net/~n6tv/Y-BOX/Features.html#Remote
>
> The following K3 macro will pulse CONFIG:DIGOUT1 ON and OFF (which pulses
> KPA500 or KPA1500 AUX Pin 8 low).  This should toggle the KPA500 ON or OFF
> (assuming the rear POWER switch is in the ON position):
>
> MN019;MP001;MN255;MN019;MP000;MN255;
>
> You may need to add a 200 ms delay in the middle of the string, like this,
> to pulse Pin 8 to ground for 200 ms, but that is usually not required.
>
> MN019;MP001;MN255;DE20;MN019;MP000;MN255;
>
> Make sure you haven't coded any "Ohs" instead of "Zeroe" in your macro.
> Make sure not to omit the last semicolon.  Make sure *CONFIG:DIGOUT1* is
> *OFF* on all bands before running the macro.
>
> On a K4, the macro commands to pulse K4 *MENU:DIGOUT1* ON and OFF for 200
> ms are more straightforward (the K3 MN commands do not work on a K4).
>
> DO1;DE020;DO0;
>
> Again, none of this will work with standard Elecraft AUX cables anywhere
> in the chain, because Elecraft AUX cables do not have anything wired to Pin
> 8 (PWR ON).  And you must not use straight DE-15 M/F cables between rig and
> amp either, unless you have a Y-BOX in series with them to open the proper
> pins (1, 4, 6, 7, and 8).
>
> K3 or K4 AUX -> Y-BOX v2.1+ "RADIO" via straight DE-15 M/M
> Y-BOX AMP AUX -> KAT500 XCVR -> via straight DE-15 M/F
> KAT500 AMP -> KPA500 AUX1 via straight DE-15 M/F
>
> For a KPA1500, omit the KAT500 from the chain:
>
> K3 or K4 AUX -> Y-BOX v2.1+ "RADIO" via straight DE-15 M/M
> Y-BOX AMP AUX -> KPA1500 AUX via straight DE-15 M/F
>
> 73,
> Bob, N6TV
> https://bit.ly/Y-BOX
>
> On Sat, Jun 27, 2026 at 11:00 AM Jack Brindle via Elecraft <
> elecraft at mailman.qth.net> wrote:
>
>> Please tell us ho you have the K3, KPA500 and KAT500 connected. I have to
>> assume there is a computer in the mix. The K3 cannot talk to the KPA500 to
>> tell is to shut off, nor can it cause the KPA500 to power up. The same is
>> true for the KAT500, although the KAT can power up on its own when power is
>> applied. A computer or other “intelligent” device is needed to tell the KPA
>> and KAT to power up. In the case of the KPA500, there are two ways to
>> remotely power it up - one is to momentarily ground the power line in the
>> AUX IO connector. This signal cannot be tied to the K3’s power signal
>> because of differences in voltage levels. Connecting them will probably be
>> a good reason to send the KPA back for repairs. The second method is to
>> send a “P” (just the P, no quotes needed) to the KPA500 when it is off
>> (using the serial port). After it powers up, you can shut it off by sending
>> the “^ON;” command to the KPA500. See the KAT500 serial command reference
>> for info on commands specific to it.
>>
>> And again, the K3 does not send data to the KPA500. The Auxbus is
>> strictly send-only from the KPA500. The only signals that go from the K3 to
>> the KPA are the band signals and PTT.
>>
>> Note that the KPA1500 and KPA500 communicate differently - I don’t have
>> an answer for Jim on his situation.
>>
>> Second, please trim your list emails when replying to digests, and follow
>> the request to change the subject line. It cuts down on the amount of stuff
>> we have to look through, and tells us which of the message you are replying
>> to.
>>
>> 73,
>> Jack W6FB
>>
>> > On Jun 27, 2026, at 12:00 PM, Joseph Koester via Elecraft <
>> elecraft at mailman.qth.net> wrote:
>> >
>> > I have a similar issue with my K3 and my KPA500. I cannot turn the amp
>> off.
>> > I can turn the tuner off but not the amplifier.
>> >
>> > Joe/W4NSA
>> >
>> > On Sat, Jun 27, 2026, 11:01 <elecraft-request at mailman.qth.net> wrote:
>> >
>> >>
>> >> Message: 1
>> >> Date: Sat, 27 Jun 2026 00:17:07 -0500
>> >> From: Jim Rhodes <jimk0xu at gmail.com>
>> >> To: elecraft at mailman.qth.net
>> >> Subject: [Elecraft] K4/KPA500 macro question
>> >> Message-ID:
>> >>        <CALhxr4ZyaBLACkEM_3O-1iwJyWgW+wgJWKEWWpQDrFbZMQLz=
>> >> w at mail.gmail.com>
>> >> Content-Type: text/plain; charset="UTF-8"
>> >>
>> >> I am trying to set up macros to turn the KPA500 on and off.  I seem to
>> have
>> >> them entered correctly in the K4D and in the KPA500 app.  But the app
>> will
>> >> turn the amp on but not off.  The K4 will turn it off but not on.
>> Object
>> >> is to get it set up for use with the K4/0.  Does anyone how I messed
>> those
>> >> up?
>> >>
>> >> Jim K0XU
>> >> jim at rhodesend.net
>
>

-- 
Jim K0XU
jim at rhodesend.net