[Elecraft] RE: K2 #4039 - Distorted transmit audio

[Stewart Baker]

On Fri, 10 Dec 2004 00:25:23 -0000, nicolas wrote:
> Hi,
> Following reports of poor transmitted audio, and aided by a fellow K2
> owner we set about a little investigation.
> What happens..
> Raspy, clipping?, (distorted by RF?), almost Dalek (For UK readers!!),
> sounding transmit audio.
> We checked the various board, joints etc, swapped things with the known
> working K2 and established..
> 1. The issue is with the control board, when swapped, it gives the same
> fault in either K2.
> 2. No obvious component problems.
> 3. Another interesting observation on both K2's, was how the 12v rail
> modulates when you transmit?

>> What do you mean by "12v rail modulates" ? Where are you seeing this effect ?
>> Assuming that you are using the same PSU for both K2's, then I would check
>> all the supply rails on the control board 12V, 8A and 5A with a DVM
>> and a scope. It sounds like a power rail rather than an RF problem.
>> Look for any effects on the rails whilst whistling into the mic.
>> Also check around the ALC circuitry.
>> 73
>> Stewart G3RXQ

> Any suggestions, where / what to look for on the control board, or other
> ideas?
> Thanks!!!
> Regards
> Nicolas
> www.m1hog.com
>
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