Doctor and patient are doing fine

A few days ago, I went out to the car as I usually do, for some lunchtime QRP.  In my haste to get everything put away after I was done, I inadvertently knocked the external battery off the car seat onto the floor. The KX3 started to move, as it was still attached, but a quick hand stopped it, and all was well. Or so I thought.

Gear on the backseat of the Jeep.

Yesterday, I went out again, and this time the KX3 wouldn't turn on. No problem, I thought to myself, the battery was probably on its way out, as it has been a while since I have given it its last drink.  So last evening, while I was attending a CERT class on animal handling during declared emergencies, I had the battery plugged in at home, charging.

When I got home, around 10:00 PM, I tried reconnecting the battery to the KX3 to see if everything was OK.  Still no sign of life - my KX3 was still flat lining..  Hmmmmmm ........ could the battery have gone totally bad?

I carried the radio down to the shack 13.8V power supply.  Viola!  It turned on! 

And then immediately turned off.


My brain went into over drive. What the %(#@*#$ was going on ?!?

I dread sending stuff out for repair.  Don't know why, I just do.  I was in the professional photographic electronics repair biz for over 20 years. I have fixed studio strobes costing well over $12,000.00.  I have taken apart digital camera backs that cost more than a Mercedes Benz. I have stared down banks of charged capacitors storing up enough electrons to supply 6,400 Joules of energy in one pop - certainly I should be able to figure out a relatively minor KX3 repair? Right?

I rolled up my sleeves and got down to it.  Obviously, this was a power problem.  But why was the rig shutting down so quickly?  Internal short?  Bad connection somewhere? Then I noticed that if I wiggled the power plug a certain way, the radio would stay on.  My mind immediately flashed back to the battery falling incident from the other day.  I must have done something to the power socket.

The power socket is the black, boxy thing to the right.

The advantage of building the KX3 (if that's what you want to call it) is that you know how it goes together, so you're not frightened at the prospect of taking it apart.  You've seen it in all its naked glory and you lovingly put it together at least once, right?  So what's the big deal in taking it apart?

Well, when you built it roughly five years ago, some of the finer details of how it went together get muddled up in the old memory banks.  That's why it's good to never toss the build manual!  Within about 5 -7 minutes I had it apart and had the display circuit in my hand.  A little extra light and a lot of extra magnification from a magnifying glass confirmed my suspicion.

The power socket is a surface mount device, just about like everything else on that display/control circuit board. The weight of the battery tugged the socket enough to unmoor it from its assigned, tinned pads.  When I would wiggle the connector "down" towards the circuit board, everything worked.  As soon as I let downward pressure go, the connector would break contact from the circuit board again and the radio would appear dead.

I ran upstairs for a pair of scrubs and to wash my hands to prep for surgery. NO! Just kidding!


I changed my soldering station tip to the skinniest one that I have for when I work on SMD devices and I re-soldered that connector onto its pads. I took great care to add just a little "extra" solder just to make sure the connection is good, solid and won't come apart so easily in the future.

I hastily (I'll get back to that in a minute) put everything together and fired the radio up. Fixed! Problem solved! High fives and happy dances all around!

I will have to go back sometime over the weekend to remove the front plexiglass display window, though.  In my haste, I wasn't so careful about finger prints.  I'll have to go back and clean that up.  Yes, I know ...... call me anal.  I can't help it!

But as this blog post says - the patient (and more importantly, the doctor) are doing just fine! And even more importantly - no return trip to Aptos!

PROGNOSIS: Excellent!  Today's lunchtime QRP session netted the following:

N0TA - SOTA peak W0C/PR-082 (Squaw Mountain) in CO on 20 Meters.
VP5/AC0W - Turks and Caicos Islands on 20 Meters
CT9/OM3RM - Madeira Island on 20 Meters.
PJ2/NF9V - Curacao on 15 Meters.

I chased KH7Y in Hawaii who was absolutely booming into NJ on 15 Meters, but could not make myself heard. Just goes to show, you can't win them all!

72 de Larry W2LJ
QRP - When you care to send the very least!
Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

6 Responses to “Doctor and patient are doing fine”

  • Glenn W9IQ:

    “What the %(#@*#$ was going on ?!?”.

    I normally enjoy your blog, Larry but this secular exhibition simply detracts value for me from this post. Please keep Matthew 12:33 et al in mind…

    – Glenn W9IQ

  • Larry W2LJ:

    OK. I’ll admit it. I was thinking “What the heck is going on?!?” Thought that might be too graphic.

  • Fred AE2DX:

    Having been in the electronic repair business for over 40 years I have found in many cases of just calmly looking at a piece of equipment under good light and magnification the problem can be seen without using any test equipment, spotting a discolored part or cold solder joint will often put you in the right spot for the trouble you might be having with that piece of equipment.

  • Glenn W9IQ:

    I understand. I should probably sign as “old Adam”. Keep up the good work for the hobby.

    – Glenn W9IQ

  • Larry W2LJ:

    Funny thing was that there was no scoring or discoloration. I would’ve suspected some sign of arcing or something like that, but there wasn’t. There also wasn’t much solder on those pads either, which was probably the root cause.

  • Mario N2HUN:

    Glad to hear you got your radio up and running again. Enjoy your lunchtime QRP sessions, it’s a great method of getting away from work for a short while and enjoying the hobby.

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