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QCX-20 audio clicking #problem

 

I just got my QCX-20 assembled and i'm having an issue I haven't seen talked about (though I could just be blind) - without plugging in headphones, I started trying to align the BPF, and couldn't get a peak (it always stayed around 4-5).? ?I looked over all the parts and solder joints and such and everything looks good.? So, I plugged in headphones to hear this loud tone when aligning - but I actually get a loud clicking as soon as the unit is powered on, which leads me to believe the problem might be elsewhere?? The sound seems to vibrate at a few Hz, and the volume is definitely affected by the volume control.? ?Plugged into my bench supply, it draws 140mA at 13.8V, and the display and menus work fine.

I'm still investigating (I have a DMM and oscilloscope, and I'm normally very good at assembly), but does this sound familiar to anyone???

Thanks!
 

Did you enable the S meter? ?On my 20m QCX it makes a sort of clicking sound with the S meter enabled. ?Disabling the S meter completely removes that clicking sound.

Curt M.
 

¿ªÔÆÌåÓý

Yup... re-solder your volume pot. ;-)

73,

Stephen
VE6SVJ

Sent from an electronic device.

On Apr 12, 2019, at 11:34, riz-qcx@... wrote:

I just got my QCX-20 assembled and i'm having an issue I haven't seen talked about (though I could just be blind) - without plugging in headphones, I started trying to align the BPF, and couldn't get a peak (it always stayed around 4-5).? ?I looked over all the parts and solder joints and such and everything looks good.? So, I plugged in headphones to hear this loud tone when aligning - but I actually get a loud clicking as soon as the unit is powered on, which leads me to believe the problem might be elsewhere?? The sound seems to vibrate at a few Hz, and the volume is definitely affected by the volume control.? ?Plugged into my bench supply, it draws 140mA at 13.8V, and the display and menus work fine.

I'm still investigating (I have a DMM and oscilloscope, and I'm normally very good at assembly), but does this sound familiar to anyone???

Thanks!

 

Nope, S-meter is not enabled - this literally starts as soon as it's powered on, even after a factory reset.
 

Hm.? I checked the pot, and it looks fine - but for good measure, I reflowed all three connections.? Didn't fix the problem.

However, I've discovered that when I key down, the clicking goes away, and I hear a tone.? On key up, the clicking is back.

It doesn't go away when I switch to Peak BPF - but its character does change, and in Peak BPF turning the cap does affect the sound a bit.

Curious.
n4qa at_hotmail.com
 

3.9 Band set for 20m ?

72? / 73,
Bill, N4QA
 

The other Q I have:? since I can't get Peak BPF over 5 turning the pot, should I add or remove turns from the larger secondary on T1?
 

Yes, band is set for 20m.? I've "factory reset" a couple times, and always set it back to 20m.
 

Check your solder connections on T1.? Measure from solder/pad and not the wire end.? A poor solder connection can cause BPF peaking issues.
 

Yeah, that was the first thing I checked - I soldered T1 before any other parts, and I made sure to test continuity from the pads.
 

I had a persistent qcx20 bug that turned out to be cold joint on upper component side layer found only by careful exam of upper board?
joints. Just a suggestion.
 

I had to put radio stuff away for a bit, and never made any progress on this.? ?I found myself with some spare time this weekend, so I dug out the QCX to see if I could make progress - unfortunately none.? I reflowed every even vaguely suspicious solder joint (and lots that weren't), but it still sounds like this:



I also went through and checked voltages on all the op amps - as far as I can tell, they look good.

Anyone got any bright ideas or hail marys?? :)??

Thanks!
 

¿ªÔÆÌåÓý

If this is the infamous "woodpecker", yes, there is a fix for it. And it's been on here in just the last few days. Unfortunately, I don't remember what that is, but I'm sure someone else will step up shortly.


On 9/29/2019 6:47 PM, riz-qcx@... wrote:

I had to put radio stuff away for a bit, and never made any progress on this.? ?I found myself with some spare time this weekend, so I dug out the QCX to see if I could make progress - unfortunately none.? I reflowed every even vaguely suspicious solder joint (and lots that weren't), but it still sounds like this:



I also went through and checked voltages on all the op amps - as far as I can tell, they look good.

Anyone got any bright ideas or hail marys?? :)??

Thanks!

HB9FIH
 

Hi, also here QCX 20 FW 1.01a received Autum 2019

Recognized :

if any character ist displayed on LCD there is an Audio noise (Decoder, S-Meter, QRG-Tuning, any change on LCD)

search now and message if solved.
---
73 de Erich

HB9FIH

HS0ZLS
 

Hi all

All the slight noises when the display updates were ELIMINATED in version 1.02 in November 2019. So all you need to do is upgrade to the latest firmware version (currently 1.03).

73 Hans G0UPL?
?

On Fri, Feb 7, 2020, 21:37 HB9FIH <erich.rieder@...> wrote:

Hi, also here QCX 20 FW 1.01a received Autum 2019

Recognized :

if any character ist displayed on LCD there is an Audio noise (Decoder, S-Meter, QRG-Tuning, any change on LCD)

search now and message if solved.
---
73 de Erich

HB9FIH

HS0ZLS

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