Topics

Select Button on Alignment QCX+ 20m


Richard M0AUW
 

I’ve Just completed my 20m QCX+, it booted up fine showing 20m in the LCD, but when I went to press the select button to get Preset nothing happens. The LCD is working and showing the correct freq and when pressing the other buttons, I get a reaction. So, it seems to be just the select button. If the LCD is working could it be a problem with the 328 microcontroller?

I have checked R44 and R45 and searched the whole board for any bad solder joints, especially the button joints, all seems OK. Any ideas?

 

Many thanks Richard M0AUW


Gary Bernard
 

I had the same problem, turned out it was a cold joint on the button.


-----Original Message-----
From: Richard M0AUW <cotswoldgent@...>
To: QRPLabs@groups.io
Sent: Mon, Sep 7, 2020 11:11 am
Subject: [QRPLabs] Select Button on Alignment QCX+ 20m

I’ve Just completed my 20m QCX+, it booted up fine showing 20m in the LCD, but when I went to press the select button to get Preset nothing happens. The LCD is working and showing the correct freq and when pressing the other buttons, I get a reaction. So, it seems to be just the select button. If the LCD is working could it be a problem with the 328 microcontroller?
I have checked R44 and R45 and searched the whole board for any bad solder joints, especially the button joints, all seems OK. Any ideas?
 
Many thanks Richard M0AUW


Alan G4ZFQ
 

I have checked R44 and R45 and searched the whole board for any bad
Richard,

Check voltages on pin 25 of the 328 when pressing the buttons. Button presses give different voltages.
I'm not sure but they should be mentioned somewhere in the manual.

73 Alan G4ZFQ


@CurtisM
 

Richard

also check the solder where this path connects with the microcontroller - few of us complete a QCX+ without missing one solder joint at least partially (for me it was a connection to the highpass pot).  glad you are almost there - look and check carefully - and enjoy the wonderful alignment experience. 

73 curt


Glen Sr
 

Richard. I have the same problem. I can raise and lower the audio noise also. Glen n8we
 

From: Richard M0AUW
Sent: Monday, September 7, 2020 1:11 PM
To: QRPLabs@groups.io
Subject: [QRPLabs] Select Button on Alignment QCX+ 20m
 

I’ve Just completed my 20m QCX+, it booted up fine showing 20m in the LCD, but when I went to press the select button to get Preset nothing happens. The LCD is working and showing the correct freq and when pressing the other buttons, I get a reaction. So, it seems to be just the select button. If the LCD is working could it be a problem with the 328 microcontroller?

I have checked R44 and R45 and searched the whole board for any bad solder joints, especially the button joints, all seems OK. Any ideas?

 

Many thanks Richard M0AUW


Steven Dick
 

The buttons are all multiplexed on a single line to share a single ATMega328p pin due to pin limitations.  See schematic explanation page 163 of the QCX+ manual.  If you have power on and, on the front panel,  you look at the ungrounded side of R46 (10K), you should see zero volts if nothing is depressed, +5V is the rotary encoder button is depressed, about 4.5 volts if the right button is depressed, and about 3.76 volts if the left button is depressed. You cal also look at the ATMega328p pin 26 for these voltages. There may be a bad solder joint or wrong values or intermixed R44, R45, or R46 resistors. If the voltages all look good, then with power off, do a direct resistance measurement from the ungrounded side of R46 right to the ATMega328, pin  26. It should be zero ohms or you have a bad solder joint or front panel connectors not fully mated.

-Steve K1RF

------ Original Message ------
From: "Glen Sr" <ghazen1@...>
Sent: 9/7/2020 4:22:21 PM
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m

Richard. I have the same problem. I can raise and lower the audio noise also. Glen n8we
 
From: Richard M0AUW
Sent: Monday, September 7, 2020 1:11 PM
To: QRPLabs@groups.io
Subject: [QRPLabs] Select Button on Alignment QCX+ 20m
 

I’ve Just completed my 20m QCX+, it booted up fine showing 20m in the LCD, but when I went to press the select button to get Preset nothing happens. The LCD is working and showing the correct freq and when pressing the other buttons, I get a reaction. So, it seems to be just the select button. If the LCD is working could it be a problem with the 328 microcontroller?

I have checked R44 and R45 and searched the whole board for any bad solder joints, especially the button joints, all seems OK. Any ideas?

 

Many thanks Richard M0AUW


Virus-free. www.avast.com


Richard M0AUW
 

Steven, 

Measuring with power on and, on the front panel,  I'm getting 1.14 volts with the left button depressed all others are correct. So, I'm presuming it's definitely the left button with some sort of cold solder joints, so I will recheck.

Many Thanks - Richard M0AUW


From: QRPLabs@groups.io <QRPLabs@groups.io> on behalf of Steven Dick <sbdick@...>
Sent: 07 September 2020 22:02,To: QRPLabs@groups.io <QRPLabs@groups.io>
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m
 
The buttons are all multiplexed on a single line to share a single ATMega328p pin due to pin limitations.  See schematic explanation page 163 of the QCX+ manual.  If you have power on and, on the front panel,  you look at the ungrounded side of R46 (10K), you should see zero volts if nothing is depressed, +5V is the rotary encoder button is depressed, about 4.5 volts if the right button is depressed, and about 3.76 volts if the left button is depressed. You cal also look at the ATMega328p pin 26 for these voltages. There may be a bad solder joint or wrong values or intermixed R44, R45, or R46 resistors. If the voltages all look good, then with power off, do a direct resistance measurement from the ungrounded side of R46 right to the ATMega328, pin  26. It should be zero ohms or you have a bad solder joint or front panel connectors not fully mated.

-Steve K1RF

------ Original Message ------
From: "Glen Sr" <ghazen1@...>
Sent: 9/7/2020 4:22:21 PM
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m

Richard. I have the same problem. I can raise and lower the audio noise also. Glen n8we
 
From: Richard M0AUW
Sent: Monday, September 7, 2020 1:11 PM
To: QRPLabs@groups.io
Subject: [QRPLabs] Select Button on Alignment QCX+ 20m
 

I’ve Just completed my 20m QCX+, it booted up fine showing 20m in the LCD, but when I went to press the select button to get Preset nothing happens. The LCD is working and showing the correct freq and when pressing the other buttons, I get a reaction. So, it seems to be just the select button. If the LCD is working could it be a problem with the 328 microcontroller?

I have checked R44 and R45 and searched the whole board for any bad solder joints, especially the button joints, all seems OK. Any ideas?

 

Many thanks Richard M0AUW


Virus-free. www.avast.com


Alan G4ZFQ
 

Measuring with power on and, on the front panel,  I'm getting 1.14 volts with the left button depressed all others are correct.
Richard,

Is R44 3K3?
You may measure this in circuit.

73 Alan G4ZFQ


Richard M0AUW
 

Hello Alan,

As per Steven K1RF instructions in previous mail, "you look at the ungrounded side of R46 (10K), you should see zero volts if nothing is depressed, +5V is the rotary encoder button is depressed, about 4.5 volts if the right button is depressed, and about 3.76 volts if the left button is depressed. You cal also look at the ATMega328p pin 26 for these voltages. There may be a bad solder joint or wrong values or intermixed R44, R45, or R46 resistors. If the voltages all look good, then with power off, do a direct resistance measurement from the ungrounded side of R46 right to the ATMega328, pin  26. It should be zero ohms or you have a bad solder joint or front panel connectors not fully mated." 
When pressing the left button I get 1.14v so I'm presuming I have a cold solder joint somewhere on that switch?

Richard M0AUW


Alan G4ZFQ
 

When pressing the left button I get 1.14v so I'm presuming I have a cold solder joint somewhere on that switch?
Richard,

Did you measure R44?

73 Alan G4ZFQ


Richard M0AUW
 

Hi Steve,

I have now carried out all the checks, including voltage and ohm checks via the ATmega328p.
The only difference is the 1.14 volts I get from pushing the left button. I've re soldered the left button joints but I'm still getting 1.14v. I'm not sure where else to check.

Richard M0AUW


Richard M0AUW
 

Hi Alan,

With the front of the kit facing me, powered up if I press R44 I get 1.14v on the left side and 4.95v on the right.

Richard M0AUW


From: QRPLabs@groups.io <QRPLabs@groups.io> on behalf of Alan G4ZFQ <alan4alan@...>
Sent: 08 September 2020 10:48
To: QRPLabs@groups.io <QRPLabs@groups.io>
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m
 
> When pressing the left button I get 1.14v so I'm presuming I have a cold
> solder joint somewhere on that switch?

  Richard,

Did you measure R44?

73 Alan G4ZFQ




Steven Dick
 

The fact that the voltage changes at all says it is probably not a cold solder joint. I would check that R44 is the correct value (3.3K). It sounds like it may be too high.

------ Original Message ------
From: "Richard M0AUW" <cotswoldgent@...>
Sent: 9/8/2020 2:47:18 AM
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m

Steven, 

Measuring with power on and, on the front panel,  I'm getting 1.14 volts with the left button depressed all others are correct. So, I'm presuming it's definitely the left button with some sort of cold solder joints, so I will recheck.

Many Thanks - Richard M0AUW


From: QRPLabs@groups.io <QRPLabs@groups.io> on behalf of Steven Dick <sbdick@...>
Sent: 07 September 2020 22:02,To: QRPLabs@groups.io <QRPLabs@groups.io>
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m
 
The buttons are all multiplexed on a single line to share a single ATMega328p pin due to pin limitations.  See schematic explanation page 163 of the QCX+ manual.  If you have power on and, on the front panel,  you look at the ungrounded side of R46 (10K), you should see zero volts if nothing is depressed, +5V is the rotary encoder button is depressed, about 4.5 volts if the right button is depressed, and about 3.76 volts if the left button is depressed. You cal also look at the ATMega328p pin 26 for these voltages. There may be a bad solder joint or wrong values or intermixed R44, R45, or R46 resistors. If the voltages all look good, then with power off, do a direct resistance measurement from the ungrounded side of R46 right to the ATMega328, pin  26. It should be zero ohms or you have a bad solder joint or front panel connectors not fully mated.

-Steve K1RF

------ Original Message ------
From: "Glen Sr" <ghazen1@...>
Sent: 9/7/2020 4:22:21 PM
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m

Richard. I have the same problem. I can raise and lower the audio noise also. Glen n8we
 
From: Richard M0AUW
Sent: Monday, September 7, 2020 1:11 PM
To: QRPLabs@groups.io
Subject: [QRPLabs] Select Button on Alignment QCX+ 20m
 

I’ve Just completed my 20m QCX+, it booted up fine showing 20m in the LCD, but when I went to press the select button to get Preset nothing happens. The LCD is working and showing the correct freq and when pressing the other buttons, I get a reaction. So, it seems to be just the select button. If the LCD is working could it be a problem with the 328 microcontroller?

I have checked R44 and R45 and searched the whole board for any bad solder joints, especially the button joints, all seems OK. Any ideas?

 

Many thanks Richard M0AUW


Virus-free. www.avast.com


Richard M0AUW
 

Hi Steven, 
Looks like you're right, R44 looks to be the 33k orange orange black red brown, instead of the 3.3k orange orange black brown brown! ( i did measure but obviously got the decimal point wrong...Doh!).

I swap them out and see how it goes....Many thanks for your help.

Richard M0AUW


Alan G4ZFQ
 

The fact that the voltage changes at all says it is probably not a cold solder joint. I would check that R44 is the correct value (3.3K). It sounds like it may be too high.
I seem to remember I suggested that 4 hours ago:-)

73 Alan G4ZFQ


Arv Evans
 

image.png

The left button (S2) completes a series circuit between 
R44 (3.3K) and R46(10K), with R44 going to +5V and 
R46 going to ground.  If the right button (S3) works 
properly then R46 is probably not the problem.  This 
leaves the value of R44 (3.3K) not being proper...or 
something miss-wired, shorted, or open someplace.  
It is just 2 resistors and a switch, so not a lot of parts 
involved.  

Current through S2, R44,  and R46 (total resistance 
of 13300 ohms) should be 5V / 13300 = 0.376 ma.
Voltage across R46 should be 13300 * 0.000376 = 
3.759V

Arv  K7HKL
_._


Arv
_._



On Tue, Sep 8, 2020 at 4:07 AM Richard M0AUW <cotswoldgent@...> wrote:
Hi Alan,

With the front of the kit facing me, powered up if I press R44 I get 1.14v on the left side and 4.95v on the right.

Richard M0AUW


From: QRPLabs@groups.io <QRPLabs@groups.io> on behalf of Alan G4ZFQ <alan4alan@...>
Sent: 08 September 2020 10:48
To: QRPLabs@groups.io <QRPLabs@groups.io>
Subject: Re: [QRPLabs] Select Button on Alignment QCX+ 20m
 
> When pressing the left button I get 1.14v so I'm presuming I have a cold
> solder joint somewhere on that switch?

  Richard,

Did you measure R44?

73 Alan G4ZFQ




N3MNT
 

Could be a simple issue.  Make sure you did not install the know too far on the shaft ( close to the case) or it will not have sufficient travel to activate the switch.