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Re: Qdx tcxo problems?
Hi
The si5351 is the faulty unit, tcxo is ok all the time, but Lo disappear when the fault occurs. By cooling down the si5351 it is ok again. This smd is too small for me to replace, I have no tools for smd-work, so the less expensive for me will be to buy a new qdx kit.
In the meantime I will cool down the unit with a little fan, then the unit is working ok .?
( I have enjoyed building simple hamradio-rx and -tx for more than 50 years, but the si5351 is too small for my eyes and hands ). Except for this the qdx-kit is the most impressive kit I have build from Qrp-labs, and the one qdx I have with no fault is monitoring wspr on 20 m 24/7.
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73 de
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Alf, la1zm |
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Re: QMX (not-plus) power issue
Hi Michael.?
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When I had a blown PA output transistor, my 12v QMX was drawing a little over 200mA on receive/idle mode. So yours is behaving a little differently at 125mA receive current draw.?
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In my case one of the 4 PA transistors had an internal short from gate to drain. With the display board removed and the QMX powered up, I could feel (and actually see, since I had an infrared camera) one of my 4 PA transistors was getting quite hot during receive, which should not occur.?
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You may need help from one of the more knowledgeable electronic gurus, like Ludwig, in diagnosing what's going on.?
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But, if you can detect one of your 4 PA transistors getting warm in receive mode, then it's probably gone bad and needs to be replaced.?
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This is more of a hit it with a hammer type of diagnosis. You may need more expert help than I can provide.?
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73 de Roy - KI0ER Littleton, Colorado USA |
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Re: iFTX
Yes !!!! El El sáb, 21 sept 2024 a la(s) 01:32, Jay Gustin via <jginaz=[email protected]> escribió:
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Re: iFTX
Here??
toggle quoted message
Show quoted text
On Friday, September 20, 2024, 8:58 PM, Luis Rogelio Galina <lu4hk@...> wrote:
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Jginaz |
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Re: iFTX
Hello ! It doesn't work for me from ligthing to USB C, I would have to buy an OTG adapter if I understand correctly El El vie, 20 sept 2024 a la(s) 11:35, Jay Gustin via <jginaz=[email protected]> escribió:
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Re: Unzipping the QMX+ firmware on a Mac?
Fred Barry Wheeler
开云体育I received an email from Hans (! Amazing customer service) that the online file was a zip file and that the QMX file was the uncompressed file - so my Mac had already decompressed the file for me. ?Thus I loaded the file directly.THANKS! F Barry Wheeler? 4508 Embleton Dr Raleigh, NC. 27612 Barry.wheeler1@... Https://www.fbarrywheeler.net 703 282 0316 On Sep 17, 2024, at 2:48?PM, Fred Barry Wheeler <fbarrywheeler@...> wrote:
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Re: QMX (not-plus) power issue
So, I put it on a buck-boost that could give me a better readout than the power bank on amperage draw. At idle, it's drawing 0.125A; transmitting on 20m, it's drawing 1.25A. At this scale, I'm assuming "0.125A" count as "substantially more" than "0.090A", so I'm betting something's blown! /m On Fri, Sep 20, 2024, at 04:55, Roy - KI0ER wrote:
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Re: QMX crashes on RF filter sweep (and other anomalies)
John,
Just saw your 2nd post.
I'm not an expert, but what you describe is exactly what happened to me on a first batch QMX+. Along with a few others I believe.
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I had mine checked and repaired by Jeff Moore who confirmed the PCM1804 chip had failed.
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BTW, mine actually transmitted fine, at least into a dummy load. Since it was obvious that received signals weren't getting through I suspected IC 407. Didn't feel up to trying to replace that one myself at the time.?
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You might contact Jeff. Look him up on QRZ at W1NC.
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63 GREG KI4NVX? |
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Re: QMX Rev 4 mid-band schematic / L405a and L405b connected to GND
There is no separate rev4 schematic - the rev3 is accurate, only one minor change on the ptt out jack for rev4.? All of the terminals of L405a/b should show DC continuity to ground and the other few test points shown in the assembly instructions. On Fri, Sep 20, 2024, 3:03 PM DH8WN via <DH8WN=[email protected]> wrote:
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Re: QMX+ High Current and Self Start
On Wed, Sep 18, 2024 at 07:38 PM, Damon wrote:
With one or more BS170’s it goes to the rails. Overload and blue smoke release if not limited.?Damon, ?
to do some investigation without damage of the BS170 you may feed the PA from a little AA cell in series with a 10 ohm resistor (see this thread 2nd post). Please install all BS170. Then check voltage at G and D of the BS170 and voltage at the pins of IC503. An oscilloscope would be perfect but values get by an DMM are also helpful.
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73 Ludwig |
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Re: QMX Rev 4 mid-band schematic / L405a and L405b connected to GND
On Fri, Sep 20, 2024 at 08:07 PM, HA5MZX wrote:
all leads connected to L405a and L405b are connected to GND. This seems suspicious to me, as the assembly manual shows on page 37 that the toroids are connected to RF IN, Hello Donat,
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and RF_IN is connected via L503 to GND. For DC L503 is only a piece of wire with nearly 0 Ohm. So don't worry (see schematics for rev. 2 and higher).
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73 Ludwig |
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Re: Thinking about a project, receiver module + VFO / sig gen
Hi Eric, I’ve been having similar thoughts and have been doing FPGA design since 1997. I have an Artix 7 dev board (Digilent Nexys Video) and a Zynq Ultrascale board (Avnet Zuboard) that I’m using for home projects I’m working on. I know both VHDL and Verilog (my preference) and could certainly help with coding and system design. I’m use AMD Vivado exclusively these days and neither of the boards requires a license. I’ve had success clocking both boards above 300 MHz. Ping me at my QRZ email if you’d like to discuss further. Tony AC9QY On Fri, Sep 20, 2024 at 9:11?AM Eric Hansen, KB1VUN via <kb1vun=[email protected]> wrote:
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Daniel Conklin
Joe AI5DD
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