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QCX 40 audio problem #qcx

Jon Reck W8REA
 

I finished my qcx 40 last weekend and it seems to receive and transmit just fine. I was real careful, double checked that I was soldering the correct components and checked each solder point with a 10x loupe as I was building.

However, when tuned to a steady, strong signal, just a tiny twitch of the volume control results in the volume going from slightly too low to eardrum piercing loud. It is very hard to find an in-between point. Is  there some way to smooth this out? I am using an old pair of low-end Sennheiser headphones, the same ones I use on my IC-7300.

Thanks,
Jon Reck
W8REA

ajparent1/KB1GMX
 

Most likely:

Bad solder connection to the ground end of the volume control.
Bad volume control.

Allison

KB3USG
 

I over-tightened my volume control.

There was even a warning in the manual and I didn't think that I could
have possibly done that. But I loosened it up a little bit and suddenly
the volume control worked as expected.

Might be an easy check to try first....

Paul

On 2019-06-05 13:43-0700, ajparent1/KB1GMX wrote:
Most likely:

Bad solder connection to the ground end of the volume control.
Bad volume control.

Allison


Jon Reck W8REA
 

Thank you, Paul and Allison.

I loosened up the lock nut on the volume control and I think that helped. There is still an annoying point where, as I increase the volume, the audio quality abruptly changes, becoming harsh and fuzzy. But there seems to be a broader range of response in the turning of the control and the abrupt change in audio quality happens at quite a loud volume, which I can avoid if careful.

Jon
W8REA

Ham Radio
 

If you have not already done so, carefully check for proper continuity between the audio pot and the corresponding pads on the board.

If no joy, try some contact cleaner/lubricant  on the pot.  Do not use regular  DeOxit on the audio pot.
--
73, Bernie, VE3FWF

SkipF, NT1G
 

I'd actually go a step further and short the wiper to ground
then test to see if the board is still microphonic.
This is basically what Q7 does during XMIT.
gl de nt1g

On Sun, Jun 9, 2019, 7:41 PM Ham Radio <bernard.murphy@...> wrote:
If you have not already done so, carefully check for proper continuity between the audio pot and the corresponding pads on the board.

If no joy, try some contact cleaner/lubricant  on the pot.  Do not use regular  DeOxit on the audio pot.
--
73, Bernie, VE3FWF