Thursday, July 26, 2012

Elecraft K3 P30 and P35 replacement

For a little over a year, I have had an intermittent problem with the K3. The problem occurred at boot-up (power-on) and at least two error messages were consistently displayed: IO TST2 ERRPL1 Once these errors appeared, the radio was unusable.

I contacted Elecraft Support and learned that these errors were most probably due to a connector failure. The culprits seemed to be the connectors between the front panel and the RF board. At Elecraft's suggestion, I purchased some DeOxit and treated the connectors. My experience was similar to other K3-owners on the Elecraft e-mail reflector – this fix only lasted a few months.

As I was getting paranoid about watching the display during boot, I decided to bite the bullet and see about a better fix.

Elecraft support advised that the best repair for this fault was to replace the original 28-pin P30 and 5-pin P35 tin-plated connectors with gold-plated ones and offered to send me the parts (at no charge) or to arrange repair. Though I am no longer a spring-chicken, I can still do through-hole soldering, so I decided to try the repair.
Important Note: I am NOT recommending you try this yourself. My advice is to return it to Elecraft. Personally, I weighed the K3 time lost, shipping + repair costs and probability of a botched job on my part and decided to give it a shot.

Before every step, I made sure that WB5BKL, the K3, tools and Earth were all at the same potential. I had a binocular magnifier, excellent illumination, an anti-static mat and a trusted soldering station available.

First I pulled the front panel assembly and then the bottom panel (I've gotten good at pulling the front panel assembly over the past year). I elected to snip off the pins as close to the plastic separator as possible. Then I carefully heated the solder joint and pulled the remainder of the pin. I later learned that it would might have been easier to remove the plastic separators – and then pull the easier-to-grasp pins.  Oh well.

Once all the pins were pulled, the most tedious task remained – most of the holes were still filled with solder. I used a fairly good solder-sucker I purchased at Frye's. This one was spring-loaded and my biggest problem was making sure the inlet was perfectly perpendicular to the RF board and heating the joint and pushing the solder-sucker trigger at the same time. Sort of like rubbing your stomach, patting your head and whistling “The Eyes of Texas” simultaneously.

All but about 5 cleared immediately. I spent quite a bit of time getting the final ones clear. I used a pin off the old connector to check the holes for clearance. I was afraid that if even one was tight, I might damage the new connector. I was also thinking that the board was through-hole plated, so the use of any force was probably a bad idea.

Finally, they were clear. I did several close inspections for solder bridges and then inserted the new connectors.


Soldering them was relatively easy. Another close inspection followed, revealing that I had missed one pin on the 5-pin connector! Yikes! Another inspection followed – and then one more. I checked the bottom of the board and touched up a couple of pins where it appeared that I had been skimpy with the solder.

One more inspection and then it was time for re-assembly.

I admit to being apprehensive about the first power-up, but everything seems to be working just fine.

Is it a permanent fix? I have no idea. Ask me in a year or so.

WB5BKL – Nick


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  2. It has been over one year and I have seen _no_ further problems. I hope that this is a permanent fix. I guess we will see in another year or so. - Nick

  3. Thanks for the nice writeup & photos!

    I just replaced the front panel connectors and the 12v KPA connectors on my early model K3. A couple of suggestions:

    For grasping the cut pins use a small alligator clip. That is much easier than trying to hold on to them with pliers.

    To clear the holes apply the iron tip to one side of the board while the solder sucker is already in place on the other side; then trigger it. No need for precise coordination.

    The new FP connectors have noticeably improved the keypad response on my K3. And the new KPA connectors fixed my ERR 12V fault. I had fun doing these mods. I guess it helps if you originally assembled your K3 as a kit.

    - Drew AF2Z