ESD sensitive tuning knob

[n3rs]

I have not posted very often to this reflector even though I get and read the daily digests, so I hope someone can be of help.
Since I got my K3 in February of last year, I have repeatedly had a problem that seems to be ESD related when USING my K3. We are currently experiencing some cold weather and this makes the problem more evident, thus my assumption that it is ESD related and this posting.

When I sit down to use the radio (which I now have on an ESD protective mat) I can almost always expect the radio to go through a rapid reboot (it turns off and then on) and lands on a new frequency as soon as I touch the main tuning knob. If I touch anything else on the radio, including the case, this rebooting does not occur. Only the main tuning knob seems to be involved. If I ground myself before touching the knob, the problem does not occur. If I am sitting there for a while and just move the chair (A Herman Miller) after grounding myself and then I touch the knob it reboots the radio.

The knob is not metal and I don't understand this weird action. I have resorted to wearing a wrist strap that is grounded (it comes with the mat), but that is really very annoying, especially during long sessions, like a contest. I have been using all sorts of radios in this station for the past 29 years and my K3 is the only one that has ever had such a problem. Any ideas??

Sig, N3RS
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[Fern Rivard]



Sig:

       I had the exact same problem with my K3 shortly after I received it. What is happening is that the encoder for vfo A is NOT grounded properly. What you'll have to do, is remove the vfo A knob and then the nut and washer holder the encoder to the front panel and very carefully remove a bit of paint just on the edges of the hole where the encoder goes thru so that the star washer will bite into the front panel to give you a proper ground. You may want to protect the front panel close to that area with some masking tape just in case your tool, to scrap a bit of that paint off, happens to slip and this way you won't damage the front panel.

      Good luck from Fern  VE7GZ

 

 

----- Original Message -----

From: [hidden email]

To: [hidden email]

Sent: Saturday, January 10, 2009 4:46 PM

Subject: [Elecraft] ESD sensitive tuning knob

I have not posted very often to this reflector even though I get and read the daily digests, so I hope someone can be of help.
Since I got my K3 in February of last year, I have repeatedly had a problem that seems to be ESD related when USING my K3. We are currently experiencing some cold weather and this makes the problem more evident, thus my assumption that it is ESD related and this posting.

When I sit down to use the radio (which I now have on an ESD protective mat) I can almost always expect the radio to go through a rapid reboot (it turns off and then on) and lands on a new frequency as soon as I touch the main tuning knob. If I touch anything else on the radio, including the case, this rebooting does not occur. Only the main tuning knob seems to be involved. If I ground myself before touching the knob, the problem does not occur. If I am sitting there for a while and just move the chair (A Herman Miller) after grounding myself and then I touch the knob it reboots the radio.

The knob is not metal and I don't understand this weird action. I have resorted to wearing a wrist strap that is grounded (it comes with the mat), but that is really very annoying, especially during long sessions, like a contest. I have been using all sorts of radios in this station for the past 29 years and my K3 is the only one that has ever had such a problem. Any ideas??

Sig, N3RS

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