Date   

Re: Type of caps to order as replacements?

Albert Rowe
 

They are Monolithic capacitors Sean.


From: QRPLabs@groups.io <QRPLabs@groups.io> on behalf of g0uvm via Groups.Io <g0uvm@...>
Sent: 01 February 2020 18:02
To: QRPLabs@groups.io <QRPLabs@groups.io>
Subject: [QRPLabs] Type of caps to order as replacements?
 
After building a 30mtr qcx and it working fine (albeit a little low on power) I have started to build a 20 mtr version.
By mistake I soldered the 102 caps in the 103 positions. I have removed the 102 (1nf) caps but need to order more and am not sure exactly what type to order. I believe they are ceramic? but they do not resemble the ceramic disc caps I'm used to. 
Any help would be greatly appreciated. 
Many thanks. 
Sean. G0uvm. 


Type of caps to order as replacements?

g0uvm@...
 

After building a 30mtr qcx and it working fine (albeit a little low on power) I have started to build a 20 mtr version.
By mistake I soldered the 102 caps in the 103 positions. I have removed the 102 (1nf) caps but need to order more and am not sure exactly what type to order. I believe they are ceramic? but they do not resemble the ceramic disc caps I'm used to. 
Any help would be greatly appreciated. 
Many thanks. 
Sean. G0uvm. 


Re: Clock Day of Week Incorrect #clock #firmware

KEN G4APB
 

Same here, running a 4 line display, showing today Saturday as Tuesday on 01 Feb 2020.

73 Ken G4apb 


Re: Clock Day of Week Incorrect #clock #firmware

Dean Smith
 

Oh dear:-{
you are not alone....
  Here i have two clocks with latest firmware both telling me it's Tuesday not Saturday.
AAARrrghh... not again!.... Hans :-)


Re: No output, Reason to worry #40m #qcx

Alan G4ZFQ
 

So, maybe more than 1 punctured gate cap?
As Jim has said, what caused it to go?
Are the BS170s all good? One thing that destroys IC3 is a drain/gate short.

73 Alan G4ZFQ


Re: No output, Reason to worry #40m #qcx

KI7MWA
 

For James: with microcontroller & LCD removed, voltage on microcontroller socket pin 17 steady at 1.09V for over a minute.  One punctured gate cap!

Some additional information (now that I've got a better handle on the troubleshooting guide): Voltages on IC3 pins while in transmit (nominal values in parens):

1: (5V square wave, ~2.5V RMS) +4.95VDC
2: (same as 1)
3: (5V square wave) 0 (zero) VDC
4: (3.3V square wave, ~ 1.65V RMS) ) 0VDC
5: (+5VDC) +4.95VDC
6: (same as 1) +4.95VDC
7: (0) 0VDC
8: (+5 VDC) 4.95VDC
9: (0) 1.3VDC
10: (same as 4) 0VDC
11: (+5VDC) 4.95VDC
12: (0) 0VDC
13: (0) 0VDC
14: (+5VDC) +4.95VDC

So, maybe more than 1 punctured gate cap?


Clock Day of Week Incorrect #clock #firmware

n0mpm
 

I noticed a few days ago that my clock running version 1.03b firmware reports the wrong day of the week.  I am pretty sure that today is Saturday, but the clock is telling me it's Tuesday!  This happens with all 4 # tags(#LA, #DA, #L3, #D3).   Things went haywire on Jan 31, 2020.  It was reporting Monday instead of Friday...
Anyone else seen this ???


Re: No output, Reason to worry #40m #qcx

James Daldry W4JED
 

Hi, KI7WMA

Yes, 9.6 megs should be big enough. Next step is to apply power with the micro and display removed and check the voltage on socket pin 17. It should be zero. You may have to wait with the meter probe connected for the gate capacitance to discharge, but it should reach zero within a second or two. If it doesn't you have a punctured gate cap on IC3. If it does go to zero, or starts at zero and stays there, we have that unicorn, a bad micro.

Jim W4JED

On 1/31/20 10:12 PM, KI7MWA via Groups.Io wrote:
Hi James, thanks for responding.  In answer to your suggestion, I pulled the microcontroller and checked resistance between socket 17 and the ground pin at the GPS antenna connection (lower-right corner, 3rd pin up).  My DVM read 9.6 Meg ohm.  Not infinite.  Big enough?


Re: No output, Reason to worry #40m #qcx

George Korper
 

Likewise. 


On Fri, Jan 31, 2020 at 11:11 PM JohnL <John.lengeling@...> wrote:
I had something like what you described and couldn’t find the root cause. I ended up performing a factory reset and the transmit output just worked after that.  Worth a shot.  I too was running 1.00g firmware. 

Johnl


Re: No output, Reason to worry #40m #qcx

JohnL
 

I had something like what you described and couldn’t find the root cause. I ended up performing a factory reset and the transmit output just worked after that.  Worth a shot.  I too was running 1.00g firmware. 

Johnl


Re: No output, Reason to worry #40m #qcx

George Korper
 

Thanks. Take a close look for solder bridges on top and bottom of board. It's tough if you don't have spare parts,  that 
has been a problem for me in Mexico so I hope it isn't a component. Solder pads are very close together and on a cursory scan I eventually spotted one pad that was really two I had bridged.
I recently soldered a component and the solder went down the leg and bridged the board on the component side!

It ain't easy but you will see something
🤓
As for skill at this, my company sent me to China to a factory where there are woman who can assemble 12 radios probably in a day ( hi hi). And they are cute and cheerful! I don't recall them boasting. 

On Fri, Jan 31, 2020, 9:12 PM KI7MWA via Groups.Io <entilleser=yahoo.com@groups.io> wrote:
George - I'm working on it...


Re: No output, Reason to worry #40m #qcx

KI7MWA
 

Just to avoid leading y'all astray, I should say that this was my first project at this level of complexity.  I managed to mount a couple of components wrongly, which I had to pull and re-mount in their correct places.  It is not impossible that, in the process, I did some damage to a trace, though I have been unable to discover anything in repeated examinations.


Re: No output, Reason to worry #40m #qcx

KI7MWA
 

George - I'm working on it...


Re: No output, Reason to worry #40m #qcx

KI7MWA
 

Hi James, thanks for responding.  In answer to your suggestion, I pulled the microcontroller and checked resistance between socket 17 and the ground pin at the GPS antenna connection (lower-right corner, 3rd pin up).  My DVM read 9.6 Meg ohm.  Not infinite.  Big enough?


Re: U3S Tutorial or Quickstart WSPR guide

George Korper
 

Please email georgekorper@...


On Fri, Jan 31, 2020, 4:40 PM wb8yyy via Groups.Io <wb8yyy=yahoo.com@groups.io> wrote:
George

Its been a while, but I had those same startup issues!  since we seem to be the only two, we could start a club.

The gps pretty much starts on its own, but look to see if we must set a menu that a gps is attached. Yes the led rhythm and heart are significant,  but the real breakthrough is seeing lat and long. That conveys all is well with timing. It took a few minutes the first time, but after this it syncs quickly.

Next challenge is PLL calibration,  and it needs more aggressive settings than default ones. Until PLL cal greatly improves your signal won't likely be in the 200 Hz passband.

I can likely help if you email me.

Curt wb8yyy


Re: U3S Tutorial or Quickstart WSPR guide

@CurtisM
 

George

Its been a while, but I had those same startup issues!  since we seem to be the only two, we could start a club.

The gps pretty much starts on its own, but look to see if we must set a menu that a gps is attached. Yes the led rhythm and heart are significant,  but the real breakthrough is seeing lat and long. That conveys all is well with timing. It took a few minutes the first time, but after this it syncs quickly.

Next challenge is PLL calibration,  and it needs more aggressive settings than default ones. Until PLL cal greatly improves your signal won't likely be in the 200 Hz passband.

I can likely help if you email me.

Curt wb8yyy


Re: No output, Reason to worry #40m #qcx

George Korper
 

It can be helpful if you send us a high res pix top and bottom, so we can help you search for the obvious. BTW this group is very supportive but it may take a couple of days. My assembly skills and the density of small parts is intimidating and every kit is a challenge. Others find it a breeze. I guess that entitlement is sometimes shared but really not helpful.


On Fri, Jan 31, 2020, 8:17 AM ae1ct1998 <AE1CT1998@...> wrote:
I've built a dozen qcx radios and never had any problems with them  not working. 

On Fri, Jan 31, 2020, 09:01 James Daldry W4JED <jim@...> wrote:

Hi, Entilleser

The line in question has 3 components attached to it, and 2 different functions. Function 1 is the MOSI signal used in programming the micro, and function 2 is to turn the alignment signal for the receiver on and off. It has no effect on the transmitter output.

Since there are the micro, IC3, and the programming connector connected together, any one of the 3, and any part of the connecting foil, can cause the problem. The simplest test to start with is to remove one of the components, by pulling the micro out of its socket. Then check the resistance from pin 17 of the micro socket to ground. Since all that's left on the line are the programming socket and a cmos input (essentially a capacitor) you should read infinite ohms with the meter probes in either direction. Infinite reading, micro problem. Any other reading, keep looking for stray wire clippings, solder whiskers, etc.

40+ years in consumer electronic service tell me that if you have a bad micro, something blew it. So micro repairs are always micro plus whatever blew it.

73

Jim W4JED

On 1/30/20 4:31 PM, entilleser via Groups.Io wrote:
No output power on my QCX40.  LPF is continuous from end to end.

On the Troubleshooting page, Hans says, in reference to IC3:

"Again the 0V and 5V in this chart, should measure pretty close to 0V and 5V. 4.8V, 4.9... fine... 0.1V, fine... but if you see 1V somewhere, then that is a reason to worry. "

I get 1 volt (+/- 0.02) on pin 9, whether in transmit or receive.  Microcontroller pin 17 (SigOut) shows continuity with pin 9 of IC3.  My microcontroller is rev T1.00g, and it is installed correctly, with pin 1 at the top-right corner.

Do I need to continue looking for a wiring fault, or just replace the microcontroller?


Re: 40 meter rig #40m #qcx40

ajparent1/KB1GMX
 

Some significant number of occurrences its soldering.

One of these are likely:
Soldered but no connection (especially the leads of T1)
Soldered, but causing shorts to adjacent connections.

The QCX where audio is not working is best to start at T1 and insure
all the wires are indeed soldered correctly.

Allison
-------------------------------
Please reply on list so we can share.
No direct email, it goes to bit bucket due address harvesting in groups.IO


Re: Value of inductance of T1

Giulio Paris
 

Good news
I wrapped the same turns on another T50-2 and this time I measured the expected value. I also redone the measurement on T1 (mounted on the PCB) and got the same value. Maybe the first measurewaswas wrong
Problem solved, thanks

--
Giulio Paris

--
IZ0FVD Giulio


Re: No output, Reason to worry #40m #qcx

ae1ct1998 <AE1CT1998@...>
 

I've built a dozen qcx radios and never had any problems with them  not working. 


On Fri, Jan 31, 2020, 09:01 James Daldry W4JED <jim@...> wrote:

Hi, Entilleser

The line in question has 3 components attached to it, and 2 different functions. Function 1 is the MOSI signal used in programming the micro, and function 2 is to turn the alignment signal for the receiver on and off. It has no effect on the transmitter output.

Since there are the micro, IC3, and the programming connector connected together, any one of the 3, and any part of the connecting foil, can cause the problem. The simplest test to start with is to remove one of the components, by pulling the micro out of its socket. Then check the resistance from pin 17 of the micro socket to ground. Since all that's left on the line are the programming socket and a cmos input (essentially a capacitor) you should read infinite ohms with the meter probes in either direction. Infinite reading, micro problem. Any other reading, keep looking for stray wire clippings, solder whiskers, etc.

40+ years in consumer electronic service tell me that if you have a bad micro, something blew it. So micro repairs are always micro plus whatever blew it.

73

Jim W4JED

On 1/30/20 4:31 PM, entilleser via Groups.Io wrote:
No output power on my QCX40.  LPF is continuous from end to end.

On the Troubleshooting page, Hans says, in reference to IC3:

"Again the 0V and 5V in this chart, should measure pretty close to 0V and 5V. 4.8V, 4.9... fine... 0.1V, fine... but if you see 1V somewhere, then that is a reason to worry. "

I get 1 volt (+/- 0.02) on pin 9, whether in transmit or receive.  Microcontroller pin 17 (SigOut) shows continuity with pin 9 of IC3.  My microcontroller is rev T1.00g, and it is installed correctly, with pin 1 at the top-right corner.

Do I need to continue looking for a wiring fault, or just replace the microcontroller?