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Bojan,

There is no T1 toroid with the VFO/Signal generator. So there is no PA 5.00 volts to the toroid
or to Q1.
Was I to buy instead the U3S that has all the parts?

Charles Brown

Hi Dan,

Looking at your RF Sweeps, it seems to me that your first section of L12 is right on (20m sweep), that the tap between 30 and 36 might be off by one turn, but not enough to warrant removing and rewinding.? Note that 30 meters is low, indicating that there may be a turn too many on the second winding (19 to 30), and 40meters is too high, meaning a turn too soon for the tap.? If the tap were moved, it would most likely move the pass bands correctly.? Again, not something that I would do as you will not notice any difference in the receiver.

I am less sure about the 80 meters sweep.? It does not show enough inductance on L12, though the dip does not indicate an L12 problem.? I would recheck the 80 meters low pass filter (LPF).? ?Count turns on the two inductors and verify the capacitors are correct.??By chance, have you verified the LPF filter selections testing that only D1 and D4 are on?? ?The other 4 should be off.

The above is my interpretation of the information.? It could be wrong, so please verify and get back to me with any errors.
73
Evan
AC9TU

On 17/08/2022 14:00, chris coleman wrote:

I have had then problem with my QDX of low signal levels and 500Hz lines on the waterfall. As others have found, it initially works and then on subsequent uses gives a low signal level.

Chris,

Is this a v3a? If so have you done the cut track requirement?

73 Alan G4ZFQ

Ok, got it sorted out. R46 was a dud. Supposed to be 10K, was only 1K (yes, color code indicated it was supposed to be 10K). Swapped it out with a fresh 10K resistor and good to go.?
Special thanks to Ron for his insight into all matters QCX+.

I have had then problem with my QDX of low signal levels and 500Hz lines on the waterfall. As others have found, it initially works and then on subsequent uses gives a low signal level. I rewound L12, reworked T2, redid virtually all solder joints and checked all component values. Unfortunately, to no avail. The transmit worked with correct power out on all frequencies, so I am sure the bandpass filters were OK. Unfortunately, by the time all of this was done, the board was a bit of a mess and so I ordered another and built this. This time I only built the receive side and left out the 80m bits. Same problem. I did not delve into the terminal facility and left this side of it as supplied. I have tried 3 different windows computers, on a windows 10 machine I get no output and on a widows 11 machine I low signal output (there may be a clue in this). Before proceeding to hack to new QDX. Has anyone any suggestions. It seems I am not alone with this problem. I was very careful in building both QDXs and so the problem might not be in the hardware. Any thoughts from anyone.
--
G4HCW

Learning that just 5 watts to antenna and bit of RF in shack can cause WSJT-X to
act up and not work right. Was using an unshielded computer motherboard. Went back
to laptop. No problem. Just an FYI.

I'm with you Martin. thank god for the big guns. ;)

Today was the 20M telescoping vertical.

On Tue, Aug 16, 2022, at 10:55 PM, <goresmith@...> wrote:

I have a similar issue and getting about 1.5v on the gates of the BS170s.? I'll check with a scope as well, but I guess this points to IC5?? I have one on order, but before attempting my first 14 pin SMD replacement, it'd be good to know if that's the likely cause!

btw - I've already replaced the BS170s and C37, rewound T1 and reflowed T1 and L14 pads.

From your description, I suspect that IC5 is toast.? The oscilloscope is the best check, as with the BS170s installed, the gate capacitance can distort the signal out of IC5.? You should get close to squarewave on all 4 MOSFETs.? If you have a dual trace or one with an external trigger, you can verify that the two sides of the push-pull amp are getting out of phase signals.

73
Evan
AC9TU

Marc,

I would run the RF and Audio sweeps in the Terminal program.? See if you are getting the upper and lower sideband separation in the audio sweep and what the RF sweep looks like on 40meters.

There is a gain setting for the audio in the Configuration function in the Terminal program.? See if increasing that raises the input meter on WSJT-X.

You can test IC5 with the Terminal transmitter test function and measure the voltage on the 4 gate pads of the BS170s without them installed.? It should be 2.5volts.

73
Evan
AC9TU

What are you using for timing the start a GPS?
Remember, WSPR "MUST" accurately start on the even minute.
--
Rob KB8RCO

On 16/08/2022 21:15, Darren KN4WML wrote:

Hello,.? ? On my QCX+ the display is always showing the top layer of blocks on the screen.

In the absence of a reply I'll start.
I guess you looked here if connections are correct the processor is not working. If voltages are OK then maybe the crystal is not working, listen for it on a radio?

. When I try to use the earlier chip, it seems to start to boot up- but then throws an error code.

What is this code? Might give a clue to someone.

Firmware is normally compatible, check
Did you try the new chip on the old QCX?

73 Alan G4ZFQ

I used a simple 7805 i(n a TO220 case) with an input and output capacitor built ?'ugly' style on a scrap of PCB. That's because I always use mine in the shack with the station power supply.?

I decided portable use was not practical as it uses too much power for any prolonged period of time.?
--
73, Dan? NM3A

Since the Ultimate 3 has a DB9 connector for the GPS input, it? would be nice if the case for the QCX+ (and indeed every piece of equipment which might eventually use a GPS) had a hole drilled for DB9 in the back. That would make it easy to unplug the the? GPS from one radio and plug it to another. One can certainly do the hole? manually, but it is quite a chore, and I do not seem able to get a good finish.

I have a problem with calibration, in items 8.11 and 8.12 of the menu.? When I plug a GPS (which I know to work well, as it is normally plugged to my Ultimate 3), it is detected all right, calibration starts as described in the manual and does steps 6 and 5, but stops at 4. What can be causing that?

Just completed a 20m unit, I have a 40m one to compare it to.?
Doesn't work like the 40. The select and exit buttons seem to work with the exception that you cannot exit out of different selections. You have to turn it off to reset it. Checked continuity of the buttons and resoldered all the IC2 connections. Resoldered JP3,4 and 5. Issue with programming? Performed a factory reset, didn't help. Unit has the AGC and TCXO installed.
Suggestions on where to go from here?

Hi Jim,

I heard US on 15 and 20 m almost all the time but best was after 20:00 UTC. After 22:00 UTC 7 Mhz was fine as well. In QRP I believe I only worked the big guns.

I use N1MM. Sometimes it stalls and is fine after restart.? For Cat I installed a Usb adapter inside the QCX and then use a normal USB cable.
Then I use the Winkeyer for the CW.

73s
Martin