Date   

Re: #20m JP 3, 4, and 5 #20m

Syd
 

I have checked for the following:

there is 5 VDC on the LCD pin 2

there is 10 VDC on the LCD pin 15

I checked the gnd path from the main pcb to the pins on the LCD, it's there

I also checked the  pot output to the LCD and found an LCD pin 3 where the adjustable voltage on the pot matches the LCD

I can see the on/off switching voltage working at JP3 pin 3

so it's looking like I am going to unassemble the LCD bd assembly and look for mistakes on the assembly.

Finally, when I get the LCD pcb apart, can I apply a 5VDC directly to the LCD power pin 2 and a adjustable VDC on pin 3 to see if the LCD lights up?
If I get desperate it would be nice to affirm that the LCD actually works.

73 wt1v


Re: Ferrite_material

jakob@...
 

Thanks for the info. Do you have the picture in higher resolution or each graph on a separate sheet, It is hard to read with older eyes.
73 de AA0JR Jakob


Re: U3S build out #u3s #gps

KEN G4APB
 

Hi Micah,
seeing you have plenty of space available, I would recommend you built your self a 12volt to 5volt linear regulator (only need 3 components) to save yourself any grief if you should forget and accidentally connect a 12 volt source to your power pole leads.

73 Ken G4APB


Re: #20m JP 3, 4, and 5 #20m

Steven Dick
 

The schematic on pages 149-150 of the manual shows signals on front panel JP1,2,3.  Not sure what you mean by "the display is truly black." Does the backlight light up?  If not, you have an open path to the LEDs in the LCD. Have you tried adjusting the contrast pot? You can test voltages at the top of the front panel pc board which go to pins 1-16 of the LCD. The LED ungrounded pin should have voltage on it and the contrast pot should move that voltage when you adjust it.  Most likely you have a bad solder joint on the front panel PCB or on one of the pins on front panel PCB JP1,2,3 or mating connectors on the main board especially on the ground pins.  It's difficult to probe these when the QCX+ is assembled but it's relatively easy to probe LCD signals at the top of the front panel PCB and trace them to their final source or destination at the processor. Probe very carefully to not short adjacent pins on the processor.

-Steve K1RF

------ Original Message ------
From: "Syd via groups.io" <nhuq1@...>
Sent: 9/17/2020 9:30:03 PM
Subject: [QRPLabs] #20m JP 3, 4, and 5

Just starting to test/align this rig. The display is all blacked out! Trying to see what is supplying the voltages and signals into the display module, I see that JP3, JP4, and JP5 are the connections to the display board and it sure would be nice to know what these three JP pins are connected to, especially the VDC and gnds!  I cannot find any place in the QCX+ manual that shows what is on these pins.  Is there a list of what is on these pins?
73 wt1v

Virus-free. www.avast.com


Re: ocxo/synth 2014 & U3S Rev2 2014 with v3.08 chip #pcbversion #u3s #ocxo #building

Graham J Smith G4NMD
 

so by new boards do you mean not the 2014 Rev2 board I have?
--
Graham J Smith
G4NMD
N4GJS


Re: QRO QSO Partybar

Shane Justice
 

John,

Well said, well made point. I suspect all us Americans who are concerned about earth shaking events would be happy to chat about it, and hear your view points from your perspective and those who have expressed concern about history and the future. You are welcome to PM those who have expressed interest and we can discuss it that way.

Best Regards,
Shane
KE7TR


On Sep 18, 2020 at 00:56, John Rabson <john.rabson07@...> wrote:

Gentlemen ,

I suggest that the manner in which the United States of America are to be governed is the affair of her citizens. QRPLabs is not a proper forum to discuss it. If you are interested in such things, there are other places on-line.

John F5VLF G3PAI
PS I have views on the matter but it would be ill-mannered to present them here

On 17 Sep 2020, at 22:30, James Daldry W4JED <jim@...> wrote:

Does he shine the flame while he shines the torch?

On 9/17/20 2:17 PM, The Crunchbird wrote:


Re: QRO QSO Partybar

John Rabson
 

Gentlemen ,

I suggest that the manner in which the United States of America are to be governed is the affair of her citizens. QRPLabs is not a proper forum to discuss it. If you are interested in such things, there are other places on-line.

John F5VLF G3PAI
PS I have views on the matter but it would be ill-mannered to present them here

On 17 Sep 2020, at 22:30, James Daldry W4JED <jim@...> wrote:

Does he shine the flame while he shines the torch?

On 9/17/20 2:17 PM, The Crunchbird wrote:


Ferrite_material

Timothy Fidler
 

New folder in Files section has been created with a graphical comparison of type 43 and 61 materials in the two hole balun ferrite format.  This is just a restatement of data that can be found on the Internet. However it save s the search.  Folder name : Ferrite_material.


Re: QCX , slow key up

Dave
 

That might do it too!

Dave

On Sep 17, 2020, at 22:06, Phil N6WKZ <n6wkz@...> wrote:

Thanks Dave,

I had the GPS plugged in when in the CW Mode. I looked at the schematic and the GPS shares the same lines as the paddle and straight key!

Phil

On 9/17/2020 6:44 PM, Dave wrote:
Sounds like you have put a wrong resistor into the keying circuit so the time constant is much higher than it is meant to be. Easy to do with those 1% resistor colour codes.

Dave
On Sep 17, 2020, at 20:51, Phil N6WKZ <n6wkz@...> wrote:
My QCX takes about 2 seconds to key-up.

I have the scope connected to a 50 ohm dummy load to monitor the output, key the on-board key and it takes 2 seconds.

Monitoring pin 16 the "key out", it goes high and then a carrier is produced, but 2 seconds later. So, it transmits "when" pin 16 goes high.

Could I have done something in software?

Any help would be appreciated!

73 Phil N6WKZ










U3S build out #u3s #gps

micah@...
 

Made a few modifications to the standard U3S case.
I haven't had DB9 cables around for years, so I nibbled the opening to fit a RJ45 jack. The connector is a panel mountable pigtail with one end cut off. For power I drilled the hole out to 22mm and added a 3D-printed Anderson Powerpole holder.
https://www.thingiverse.com/thing:2580868

For the GPS, I used the case from a roadkill TV box. It already had a RJ45 jack, but sadly it was corroded, so I superglued in a RJ45 breakout. Now I can use a standard shielded Cat7 cable between the two. To prevent future-me from doing something stupid like plugging in a live Ethernet cable, I used the 4 wires not normally used in Ethernet.

Going through initial setup & calibration tomorrow.


Re: #20m JP 3, 4, and 5 #20m

Evan Hand
 

Syd,
The pins are labeled on the schematic.  You will find JP5 between C21 and C22 above Q7, JP3 and JP4 are to the right of IC2.  I believe that is the only place that the jumpers are documented.

73
Evan
AC9TU


Re: QCX , slow key up

Phil N6WKZ
 

Thanks Dave,

I had the GPS plugged in when in the CW Mode. I looked at the schematic and the GPS shares the same lines as the paddle and straight key!

Phil

On 9/17/2020 6:44 PM, Dave wrote:
Sounds like you have put a wrong resistor into the keying circuit so the time constant is much higher than it is meant to be. Easy to do with those 1% resistor colour codes.

Dave
On Sep 17, 2020, at 20:51, Phil N6WKZ <n6wkz@...> wrote:

My QCX takes about 2 seconds to key-up.

I have the scope connected to a 50 ohm dummy load to monitor the output, key the on-board key and it takes 2 seconds.

Monitoring pin 16 the "key out", it goes high and then a carrier is produced, but 2 seconds later. So, it transmits "when" pin 16 goes high.

Could I have done something in software?

Any help would be appreciated!

73 Phil N6WKZ







Re: #20m JP 3, 4, and 5 #20m

J Ramos <joshramos@...>
 

Did you try adjusting the contrast pot for the LCD? Sections 6.1 and 6.2 in the manual have a few things to check that might solve what you’re seeing.

 

73

AE0CM


Re: QCX , slow key up

Dave
 

Sounds like you have put a wrong resistor into the keying circuit so the time constant is much higher than it is meant to be. Easy to do with those 1% resistor colour codes.

Dave

On Sep 17, 2020, at 20:51, Phil N6WKZ <n6wkz@...> wrote:

My QCX takes about 2 seconds to key-up.

I have the scope connected to a 50 ohm dummy load to monitor the output, key the on-board key and it takes 2 seconds.

Monitoring pin 16 the "key out", it goes high and then a carrier is produced, but 2 seconds later. So, it transmits "when" pin 16 goes high.

Could I have done something in software?

Any help would be appreciated!

73 Phil N6WKZ






#20m JP 3, 4, and 5 #20m

Syd
 

Just starting to test/align this rig. The display is all blacked out! Trying to see what is supplying the voltages and signals into the display module, I see that JP3, JP4, and JP5 are the connections to the display board and it sure would be nice to know what these three JP pins are connected to, especially the VDC and gnds!  I cannot find any place in the QCX+ manual that shows what is on these pins.  Is there a list of what is on these pins?
73 wt1v


QCX , slow key up

Phil N6WKZ
 

My QCX takes about 2 seconds to key-up.

I have the scope connected to a 50 ohm dummy load to monitor the output, key the on-board key and it takes 2 seconds.

Monitoring pin 16 the "key out", it goes high and then a carrier is produced, but 2 seconds later. So, it transmits "when" pin 16 goes high.

Could I have done something in software?

Any help would be appreciated!

73 Phil N6WKZ


Re: QRP-Labs 50 W Amplifier - low power output

ajparent1/KB1GMX
 

Everyone,
Without sufficient drive the amp does not work.  The QCX-40 should easily do
4+ watts and 1.5 is far below normal.

Now the amp if your doing 1.5W in the first thing is an attenuator for the expected
4++W  That's R1,2 and R3.  So you are under powered!  

Add to that Class C amps need and expect a healthy and heafty] drive for
expected power.  If you under-drive them they perform terrible, as in low
power out, possible oscillations, and poor gain.

So for those that claim "I did everything right."  the answer is no you
have not.   The amp expects enough drive or it will deliver far less
then expected.   Reminder Class C is not linear, so less than half
power in will be significantly less than half power out.  As a reminder
on 40m most QCX do 4-5W and 1.5 is well under that.

NOTE:  for 1.5W drive to get 50W the amp would need to have a
gain of near 20DB {allowing for the attenuator] and neither the
RD or IRF parts will do that.  

So in all likelihood the amp is working, no question the QCX is not
100% consider that.

No amount of parts replaced and mods applied to the amp fixes that.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: QCX-20 Power Out - Success! #20m

Daniel Walter
 

Update and further improvements:

Bob, thanks for the info. My only electronics expertise is on-the-avocation training, too. Good job on your first contact with it and the antenna. Hopefully you've made many more since.

I got to thinking about your success with toroid manipulation so I looked into Hans' tips on tuning the LPF and did the following.

So, I got to fiddling with the toroids. 
L4- compress windings> decreased power; returned to spread
L1-     "             "       > increased power
L2-        "          "       >  decreased power
L3-        "          "       >  decreased power
L2&L3-  "          "       >  bigger decrease in power
 
So, removed 1 turn from L1, L2 & L3 (in steps.) (I was wrong about this not making a difference.)
L1, L2, & L3- spread as much as possible> moderate increase in power
L2 compress winding> further increase in power
 
Power out now about 5 W, which is where it will stay.
 
Bottom line, I believe the C25 & C26 were probably bad, but C27 & C28 probably were okay, although I really can't be sure as I replaced all 4 at the same time with no testing in between. Prior to taking turns off the toroids, I replaced C30 with no change in operation, so C30 definitely was okay. The rest of the issues were with the toroids. Tx efficiency now 84%, just like my QCX-40. It was 55% before the first intervention and 75% after replacing the capacitors. Also replaced Atmega328 with 1.05 firmware.
 
 
 
As I also wanted to change the firmware chip to 1.05 in my QCX-40, I got to fiddling with the toroids in that as well. 
By spreading L1/L3 as much as possible and bunching L2 as much as possible, I actually got an increase from 4.8 W to 6.5W out! It increased the current draw to 700 mA total on Tx, so I spread the L2 turns a bit to get back to 5.5 W. Current draw now 620 mA (500 mA over Rx current) total on Tx. Tx efficiency still 84%, as it was with the 4.8 W output. 
 
That means just over 0.8 W is going up as heat somewhere in each radio. If it's all in the MPS170s, that's a bit over 1/4 W per transistor and they should be able to handle that. However, probably some is being dissipated in Q6, L4 and the LPF. So I've learned a lot and improved my radios as well! 

Now as soon as the QCX mini is out, I'm going to need a 30m and 15m version and maybe a 10m??? Of course, by then the QSX will be out.....
--
73, Dan  NM3A


Re: ocxo/synth 2014 & U3S Rev2 2014 with v3.08 chip #pcbversion #u3s #ocxo #building

Mike Berg
 

I believe the pin was removed to be compatible with the old 9850 type oscillator.

The new Si5351a synth board has pin 12 grounded and your U3S pin 12 should be as well.
Mike

 


Re: QRO QSO Partybar

James Daldry W4JED
 

Does he shine the flame while he shines the torch?

On 9/17/20 2:17 PM, The Crunchbird wrote: