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

Mounting an AME Mini-B Single Lever Paddle

In 2011, I bought an American Morse Equipment Mini-B Single Lever Paddle kit for use in the Flight of the Bumblebees.

The paddle is nicely made and the kit went together well, but there is one 'feature' that would make me rate it 4.5 out of 5 on eHam.  There is only one mounting screw.

The FotBBs event encourages portable operation, so I set up near Longhorn Cavern State Park here in Texas.  At the start of the contest it was 104F and at the end 108F.  I had to hold the paddle to keep it from rotating from my heavy-handed keying.  After a few QSOs the K1 began inserting a few extra dits and dahs.  I finally noticed that the combination of sweat and my brushing against the exposed dot and dash adjustment screws were the cause.  I decided that this year, I would mount the paddle more securely.


I decided to place a stop inside the key base instead of outside (which would have been much easier).

 First I traced the shape of the bottom of the paddle on paper using a pencil lead as shown here.  On the same paper, I made sure I knew the location of the single screw.




I then carefully cut out the tracing and transferred the pattern to two tongue depressors I had glued together (they were handy and two were about the right thickness).  I then carved away everything that did not look like the hole in the base  :-) , leaving an opening for the cable connection.






I glued the stop to my small clipboard and drilled holes for the single screw and a tie-wrap for the cable.




 Here is a picture of everything assembled.  I hope that this and lower temperatures will make the 2012 FotBBs more enjoyable.

Nick - WB5BKL

Airhead Idiot Light Repair

Not really Amateur Radio related, but recently the turn signal idiot light on the 1974 R90/6 sidecar rig went intermittent and then failed.  I opened up the instrument housing hoping that it was just a bulb but found that the problem was corrosion at the bulb connection.

BMW used a printed circuit board-like material to connect the various lamps within the instrument housing.  I guess it was a good/cheap engineering solution at the time, but after 38 years, it's now problematic.

The issue is with the thin strips of copper foil that make the connections to the bulb holders.  Corrosion ate through one of the strips.  A new replacement assembly is NLA, so I decided to repair it.

Here are images of new and used with the copper 'tabs' visible.  The bulb holders plug into the rectangular holes, contacting the foil tabs on each side.

With the bulb holder in place, a VOM revealed that the problem was only on one side.  A foil tab was missing (the bottom hole, right- side in these views).


My solution was to first carefully clean the metal tab on the right side of the bulb holder.  Then I carefully lifted the top plastic film away from the copper portion of the flexible printed circuit and carefully cleaned a spot on the remaining portion of the broken copper foil.

Using a tiny soldering iron and high-quality rosin-core solder I connected a very small piece of stranded hookup wire between the two.

Problem solved.  And the holder can still be removed for bulb replacement.

If you need to try this repair, here are several thoughts:

If you are not pretty darn good at electronic soldering, I would get everything ready and take it to an expert.  Also, removing the bulb holder assembly and holding it up to a light makes circuit tracing much easier.  The wire I used was from a scrap piece of LAN cable.

Nick - WB5BKL