K2 VFO/ALC issues

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K2 VFO/ALC issues

AI4NS
I recently bought a used K2/10 and the S-Meter does not work. I am looking
at the K2 VFO/ALC mod and have a question about the 1N4148s that are added
to Q18.

This one has a 1N4148 installed on the bottom of the board anode to cathode
across D13, and no diode from Q18-S to ground. Was the additional diode
part of another mod? Seems to me that it would defeat the purpose of D13.

Mike
AI4NS
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Re: K2 VFO/ALC issues

Don Wilhelm
Mike,

What is the serial number of your K2?  That is helpful information - the
Field Test K2s (SN 100 or less) are a bit different than the Rev A K2.

There should be only one diode from Q18 gate to ground.  The anode
connects to the gate and the cathode to ground.

While the VFO/ALC mod is a benefit, it will not produce any change in
the S-meter.

As for the S-meter problem, determine if it is an LED display problem or
a problem with the actual S-meter circuit.  Rotate the RF Gain control
from full clockwise slowly to the CCW position.  If the LED display is
working, you will see the S-meter indication increase.
If it does not, you have a display problem - reflow the soldering on the
LED bargraph and Front Panel RP2, then check again.

73,
Don W3FPR

On 5/31/2019 9:42 PM, Mike Short wrote:

> I recently bought a used K2/10 and the S-Meter does not work. I am looking
> at the K2 VFO/ALC mod and have a question about the 1N4148s that are added
> to Q18.
>
> This one has a 1N4148 installed on the bottom of the board anode to cathode
> across D13, and no diode from Q18-S to ground. Was the additional diode
> part of another mod? Seems to me that it would defeat the purpose of D13.
>
> Mike
> AI4NS
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html