Date   

Re: D33 #qcxmini

KB9NBL
 

When I grow up I want to be just like Dan ;-)


I took care of my OCD and just changed it around.
Thanks for all the input.
Pics of the new arrangement


Re: D33 #qcxmini

ke9uw
 

One could grind the corner edge off the diode...probably.


Re: D33 #qcxmini

ke9uw
 

It looks like there is no updated assembly manual or pictures of the Rev 2 board. But there is a mention on the website that things have been repositioned in that area for a larger 5 volt regulator. One can assume that the diode may not fit flat on it's cylindrical bottom.
I would like to see at least one picture of the new populated board...that should not take too much time away from the more productive happenings at QRP Labs, eh?


Re: D33 #qcxmini

Jim Painter
 

Always listen to Dan. He is very wise.

Jim....KQ3S


On May 4, 2021, at 5:13 AM, Daniel Walter via groups.io <nm3a@...> wrote:

James, 
I believe I cocked D33 off to the side to avoid hitting the controls board. 
<224FD9BA-4F96-4BF0-AA70-CD2E5A5961A2.jpeg>
<6B01961D-767A-417D-B986-5CA6045EE8E6.jpeg>

--
73, Dan  NM3A


Re: #u3s #wspr Resets on 10m when RF adjust above about 50mW #u3s #wspr

Alan G4ZFQ
 

My desire would be about 100mW on 10m.  Whatever power is output on 40, 20, and 15m would be acceptable.
If I am limited to 50mW, then I will switch back to 5V for PA and uP and go with it.
Rob,

That's about what I get, 100mW @ 5V. Measured with a calibrated meter.
Are you sure you are measuring accurately? It is not easy to be certain of such low powers.

What happens at a higher voltage is strange. Does the current rise? Measuring the current taken is a good pointer to what is happening and, as the manual says, is the recommended way to set the bias level. Simply set your multimeter to mA and connect in series with the PSU.


73 Alan G4ZFQ


Re: #u3s #wspr Resets on 10m when RF adjust above about 50mW #u3s #wspr

Rob Giuliano
 

On Mon, May 3, 2021 at 10:05 AM, Alan G4ZFQ wrote:
Rob,
The bias control is not a power control unless you want to reduce power
from the optimum bias setting, where the monitored current consumption
just starts increasing.

73 Alan G4ZFQ
Running off the 5V power, I get ~50mW output. No resets.
Previous posts had other users reporting higher output on 10m than I was getting.  This is why I thought I could do better, so I started looking for ways to get that.
There were suggestions of using 8V for the PA.  I had an adjustable 45W wall wart with output options of: 5, 6, 7.5, 9, 12, 13.5, and 15V at max 3 amps.

I changed to the 7.5V for the PA (different regulators for 5V discussed earlier). 
When the bias control was set at a value I was comfortable with (about 600mW on 40m), all was great until I turned on 10m and the unit reset.
When I adjust the output on 10m such that it doesn't reset (~50mW), there is no benefit in the increased PA voltage. 

My desire would be about 100mW on 10m.  Whatever power is output on 40, 20, and 15m would be acceptable.
If I am limited to 50mW, then I will switch back to 5V for PA and uP and go with it.


Re: D33 #qcxmini

KB9NBL
 

Daniel
Believe it or not that's the way I did it originally because of the reposition on the PCB board.
Then I second guessed myself and took it off and bent it around the other way, because I thought space was at the premium in the body of the diode needs to be to the inside of the edge of the PCB board. It doesn't now that I have it all assembled.
I'll just pull it off and mount it the way you have it.

Thanks so much for your help

73
James


Re: D33 #qcxmini

Daniel Walter
 

James, 
I believe I cocked D33 off to the side to avoid hitting the controls board. 
--
73, Dan  NM3A


Re: QSX + and AGC

Lex PH2LB
 

Just ordered 2 of them.

Could have build the circuit my self on a small PCB, but it looks nice, the price is fair and small sellers need to be supported. 


--

73 Lex PH2LB 

https://www.ph2lb.nl/


Re: D33 #qcxmini

KB9NBL
 

Ron,
Don't want to see any "Magic Smoke" tomorrow when I fire it up. ;-)

Nite

James


Re: D33 #qcxmini

KB9NBL
 

Ron,
Thanks for the help.
I will live with it. I agree the 75M05 could be out of alignment. 
You have a great evening

Cheers

James


Re: D33 #qcxmini

Ronald Taylor
 

Thanks. I see now. It’s a little crooked looking but as long as it doesn’t touch the control board when it’s installed it should be fine. I’ve only had one Rev 2 board here and did not see that with it. Maybe you can check to see if the 78M05 is installed slightly out of place toward the left. 

On Mon, May 3, 2021 at 19:45 KB9NBL <mtminstr@...> wrote:
It is standing up, not laying down.
It's not seated to the PCB because it's hitting the bottom of the 78M05.


Re: D33 #qcxmini

KB9NBL
 

It is standing up, not laying down.
It's not seated to the PCB because it's hitting the bottom of the 78M05.


Re: D33 #qcxmini

Ronald Taylor
 

James that diode is supposed to stand up on the PCB. It doesn’t lay down. Is that what you meant by “won’t sit flat on the PCB”? 

Ron

On Mon, May 3, 2021 at 19:04 KB9NBL <mtminstr@...> wrote:
Question,
Does D33 (1N5819) wind up cocked off to the side after it's place on the PCB was revised on REV 2? It won't sit flat on the PCB. Am I missing something? The radio is done, but it still bugs me.

Thanks for any comments that help
Regards
James



D33 #qcxmini

KB9NBL
 

Question,
Does D33 (1N5819) wind up cocked off to the side after it's place on the PCB was revised on REV 2? It won't sit flat on the PCB. Am I missing something? The radio is done, but it still bugs me.

Thanks for any comments that help
Regards
James



Re: QCX-40 Microprocessor Blown?

Ronald Taylor
 

You can easily verify that by lifting one lead of one of the diodes. If it’s the only short then you are probably at the source of the problem. I know what you mean about the shortage of chips. I had to wait a few months for a package of 10 of those. 

Ron

On Mon, May 3, 2021 at 15:15 Cory KG7BBV <cory.goates@...> wrote:
Ron

That's what I thought as well. My suspicion is it's IC1 (the SI5351) as the pin that got shorted to 13.8V is also connected to one of the inputs to IC1. But I'll need to verify.

A quick search online is showing everyone is out of stock of SI5351 chips. Might need to shelve this project for a while...
--
Cory, KG7BBV


Re: QCX-40 Microprocessor Blown?

Cory KG7BBV
 

Ron

That's what I thought as well. My suspicion is it's IC1 (the SI5351) as the pin that got shorted to 13.8V is also connected to one of the inputs to IC1. But I'll need to verify.

A quick search online is showing everyone is out of stock of SI5351 chips. Might need to shelve this project for a while...
--
Cory, KG7BBV


Re: Modifications for Rev 2 board of QCX needed? #sidetone #qcx

 

Hans has answered my question off list.  I have asked his permission to post his reply


73, Bernie, VE3FWF
(most typos in this message have been generated by highly sophisticated auto-correction software)


Re: QCX-40 Microprocessor Blown?

Ronald Taylor
 

Hi Cory. Yes it seems there is a short on the 5 volt bus somewhere. It needs to be isolated. One quick test you can do to also isolate IC3 from the 5v bus is to use a very sharp pair of snips and cut pin 14 on top of the board (it can easily be re-soldered). You can isolate IC1 by lifting one lead of either D1 or D2. IC4 is a little tougher but I've been able to isolate it by using a dental pick and lifting pin 16 while heating it. Isolate one of these at a time till you find the culprit. Good luck.

Ron

On Mon, May 3, 2021 at 2:04 PM Cory KG7BBV <cory.goates@...> wrote:
When I turn the radio on, the 5V regulator voltage starts out at about 2.5V and then slowly drops to about 0.5V. This occurs even after I pull the microprocessor out. That makes me think I've blown some other component. The LCD screen does still light up.
--
Cory, KG7BBV


Re: QCX-40 Microprocessor Blown?

Cory KG7BBV
 

When I turn the radio on, the 5V regulator voltage starts out at about 2.5V and then slowly drops to about 0.5V. This occurs even after I pull the microprocessor out. That makes me think I've blown some other component. The LCD screen does still light up.
--
Cory, KG7BBV

7501 - 7520 of 72343