[Elecraft] K2 K2/100 post FD review

[Mike Kopacki]

I didn’t have ring connectors big enough but I did have spade connectors. I crimped and soldered them but there was no change in the voltage readings during receive and transmit. 

Is it possible that the power supply is failing?

Why, if the voltage drops during transmit to 11.6V, does the radio still put out 100W on 30, 40 and 80 meters?

Thanks,
Mike NJ2OM 

> On Jun 30, 2020, at 6:55 PM, Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
> Mike,
> 
> The red and black assembly is an Anderson Power Pole connector - commonly called APP.
> 
> For the small receive current drawn, the voltage drop in the wire and connectors should be close to zero, so the 0.2 volts is significant for #12 wire unless there is something not properly tightened on the connectors.  The drop will be more substantial with the increased current during transmit at 100 watts.
> 
> Banana plugs and jacks can be used to carry a heavy current, but some of the ones I have seen have a poor contact method of fastening the wire to the banana plugs - properly installed wires on banana plugs are good for up to 30 to 50 amps.  Is there any way you can connect ring terminals onto those power supply terminals?  Like removing the outer nuts from the terminals - if so then switch to the ring terminals.
> 
> 73,
> Don W3FPR
> 
>> On 6/30/2020 6:21 PM, Mike Kopacki wrote:
>> 
>> Don, don’t know what you mean by the APP assembly.
>> 
>> I can only see one metal part on the inside of the red and black connectors that plug into the K2.  I assume that is the “contact blade”?  I see nothing else on the inside.
>> 
>> But here is a possible problem, that I will throw out, knowing full well that some will think I am not very smart…..I had to buy banana plugs to make the power cable, which is part of the KPA-100 assembly instructions. When I received them from MFJ, model MFJ-7713, it was a solderless type that I had never seen before.  I talked to three people at MFJ, none could explain how the wire attached to the plug.  The third guy hung up on me.
>> 
>> So I connected the wire to the plug the only way I could see, but the configuration of the plug still eludes me.
>> 
>> The P/S output is 13.6V.  I’m seeing 13.1V at the K2.  If the normal drop is .3V, it should read 13.3V at the K2.  Is the difference of .2V “substantial”?
>> 
>> Mike NJ2OM
>> 
>> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10
>> 
>> *From: *Don Wilhelm <mailto:donwilh at embarqmail.com>
>> *Sent: *Tuesday, June 30, 2020 6:01 PM
>> *To: *Mike Kopacki <mailto:mikekopacki at gmail.com>
>> *Cc: *elecraft at mailman qth. net <mailto:elecraft at mailman.qth.net>
>> *Subject: *Re: [Elecraft] K2 K2/100 post FD review
>> 
>> Mike,
>> 
>> You should have only 0.3 volts drop IN the K2 itself, so given your
>> 
>> display of 13.1 volts on the K2, that says you have a substantial
>> 
>> voltage drop in the power cable.
>> 
>> Is it wired directly to the power supply? Are all the connections
>> 
>> tight?  Is the APP assembly at the K2 correct?  Look at the end of the
>> 
>> connector - do you see only the contact blade? or can you see the end of
>> 
>> the spring finger under the contact blade visible?  If the spring finger
>> 
>> is visible, the contact blades have not been pushed in far enough -
>> 
>> apply pressure to the back to seat the connector.
>> 
>> Make the same visual check on the APP connector mounted in the KPA100.
>> 
>> If it needs correction, you will have to get inside the KPA100 to
>> 
>> correct it.
>> 
>> 73,
>> 
>> Don W3FPR
>> 
>> On 6/30/2020 5:32 PM, Mike Kopacki wrote:
>> 
>> > Don...
>> 
>> >
>> 
>> > The power supply is an MFJ 13.8V/25A switching power supply. It measures 13.63V at the terminals.
>> 
>> >
>> 
>> > The K2 shows 13.1V in receive mode.
>> 
>> >
>> 
>> > During transmit on all bands, the K2 shows 11.3-11.9V, depending on the band.
>> 
>> >
>> 
>> > All the power connections appear to be tight.
>> 
>> >
>> 
>> > Thanks,
>> 
>> > Mike NJ2OM
>> 
>> >
>> 
>> >
>> 
>