KX2 encoder issue - solved

Equipment Radios & Power
1

My AF gain encoder on my KX2 has completely stopped working without any previous defects.

Interestingly, the software jumps out of e.g. b. WPM mode returns to AF mode when rotating. So it reacts but doesn’t change the value. That’s why I don’t assume 100% that the encoder is defective.

Now my thoughts.

Could it be that a bit has “fallen” in the firmware? Then a total EEreset would be required. But first I have to save the configuration.

If not, the encoder is as usual defective and I have to replace it. Armin, DL6GCA has already done that once and thankfully ordered 2 encoders for me. So I use the desoldering iron I gave away again and pray that I don’t cause any more damage.

Keep your fingers crossed for me. Do you have any tips?

73 Chris

3 Likes
2

If you haven’t already done so, you can reload the entire firmware (click on all available).

And of course, a thorough inspection of the encoder would also be necessary. For example, does the encoder shaft wobble back and forth?

An idea for opening and assembling the KX2 case can be found here:

HB9BCB - How to Unscrew the KX2

KX2 VFO Encoder issue

2 Likes
3

Hi Christoph, from your brief description do you mean trouble with:

  1. AF GAIN/MON – when rotating the knob, does the KX2 display “AF nn” but the number nn is frozen or does it not even appear? OR …
  2. KYR-SPT/MIC – KX2 in SSB mode and rotating the knob, does the KX2 display “MIC nn” but the number is frozen or does it not even appear?
2 Likes
4

Quick response … 1

Tnx Chris

1 Like
5

Heinz, thanks for the tip. I already found your post on the KX forum. Unfortunately, your link no longer works.

It’s clear now that it’s the encoder. However, before desoldering it, I’ll test once more to see if it’s still switching.

73, Chris

1 Like
6

Somewhere, I read that you can bring an encoder back to life with just a single drop of contact cleaner. Without any hope of success, three days ago I used a needle to apply a tiny amount of Ballistol between the shaft and the housing. I then positioned the KX2 vertically.

20260525_163441
20260525_1634411920×1080 275 KB

And—lo and behold—it worked! I’m curious to see how long it lasts. By the way, Ballistol is a gun oil—so, in a sense, it was an oil change.

73, Chris

3 Likes
7

On the internet, it is recommended to rinse contacts with isopropyl alcohol after treating them with Ballistol.

The manufacturer states: “For this reason, Ballistol has been used for decades as a contact spray or contact oil for electrical and electronic conductors. However, one should ensure that the remaining Ballistol film is not too thick, as Ballistol itself does not conduct electricity.”

2 Likes
8

Hope dies last, as they say. So we’re all hoping with you, Chris.

Looking at the disassembled new encoder pictured below, what appears blurry at first glance is grease trapped between the upper and lower parts of the encoder housing …

IMG_1306
IMG_13061614×1095 514 KB

3 Likes
9

So far, I haven’t had any problems with the encoders on my KX2. So I have a few general questions:

  • What kind of solder do you use when working on the encoders? Lead-free or leaded?
  • What flux do you recommend for the solder you’re using?
  • Is there a particularly good Solder wick for this kind of work?

Thanks a lot. I hope I won’t need the recommendations, hi.

73, Wolf
DL2KI

1 Like
10

I replaced two encoders: a small one and the VFO.

Unfortunately, the solder on the circuit board isn’t very fluid. I applied fresh solder in several stages and then removed it with a desoldering pump.

73 Armin

2 Likes
11

That is my motto, Heinz—whether reactivating an encoder or making a S2S contact on 2m in CW over 550km (tnx to Mario DJ2MX).

Your picture showing the inner workings of an encoder is very interesting. Years ago, I wrote a simple script for this, but I’ve since forgotten everything. Now I using a library, shame on me.

Is it the case that one row of contacts triggers slightly ahead of the other when turning to the left, and vice versa?

73 Chris

1 Like
12

Yes, look up quadrature encoder Chris.

1 Like
13

Exactly, you might have seen the nice illustration on Wikipedia

Wiki - Incremental Encoder

The encoder used is a Bourns PEC11R-4015F-S0018 with switch (incremental 2-bit quadrature code, 18 pulses per revolution (PPR)).

2 Likes