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There's a vast amount on this group on this subject.? The trouble is that it's such an active group that the information is ephemeral. The search isn't very good.? Is there a way to collate the good information and put it in one place where it can be found easily?

Fundamentally the first thing to check is that you have power to the processor.? You should have 2.5 to 3.3V on the VDD line when you press the left encoder button. It should stay on after you release the button.? The current taken should be a little under 200 mA.? If you don't have voltage at all the MCU won't start and until it does the power won't stay on.

There's a row of 10 holes on the top left side of the main board.? The third from the left is VDD.

If you don't have power go through the circuit to try to find out why.? I posted a suggested guide to checking the PSU boards independently of the main board which might help.

Chris, G5CTH

?Hi Alan

""Is there a problem with the reliability of the MCU/EEPROMs, post-COVID???? .....ANY THOUGHTS...""

Might want to check for bent pins

Mine were spred too wide and had to be adjusted before insertion into socket
My 'adjustment' was not perfect and had to be repeated

re?? ""reliability of the MCU/EEPROMs""
Back in the day (I retired 1997) some devices had a limited number of read/write cycles
I'm 99.999% sure that is not the case here
but would be interested to know how often Hans writes to EEPROM after inital programming :>)

??? COVID? ...? I'm my humble opinion was a political football

73 73
John
N3AAZ

Just to help.

I have not got any hot or burnt components.
I checked all the things mentioned in the build manual.
I do hear slight pop noises when I press the left encoder.

Mike

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Another way: I tune my antenna with my NanoVNA then disconnect the NanoVNA and connect the QDX.
73 - Pierre - FK8IH

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Yes, but that's to the start of the list. Where are they at now? ;-)

It's really simple, the list keeps being updated.

As kits are assembled they are taken off the list and everyone under them moves up.

Chris, G5CTH

hi

If you get rid off the BS170s

IC5's output must be around 10mW

You can manage this level easier, even with an trim pot.

If you can get an TinySA, life would be easier
73

muhsin TA1MHS

I read too often this event
and would like share (maybe a less known) technique to safeguard finals while tuning up is by not letting SWR (power) get back to the transmitter

Just put a simple 3 dB? pad between the TX and? tuner

10 dB is even safer but loweres the meter reading an order of magnitude

Inline Bridge Circuits with diode (either 1n4148 or more sensitive 1n34) indicate by either dc Volt meter or LED (some read forward and reflected) will drop reflected power apx 50 %

Safests of both techniques
put 3 dB pad in front of bridge
That is...
From TX to pad to bridge to ant-marcher

Tune ur ant-matcher for best reading
remove or switch out pad/bridge
Then tweek ant-matcher?? :>)

72 73
Johh
N3AAZ

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Hello folks,
Recently got 2 QCU kits and just finished assembly. Turn-on and calibration OK. Working FB.
After several days of 24-hr running one unit stopped sending CW idents and any other CW-based mode [DFCW, QRSS FSK etc]
other modes, including WSPR are OK.
This unit resets to the start-up screen if/when the "CW"-based mode is called up. For example: If WSPR is followed by QRSS, the unit re-starts at the very start of QRSS - start-up screen then back to first mode/entry item. If left running just WSPR, for instance, runs OK.
Several "resets" of the unit do not resolve the problem.
I can confirm that there is no overheating problem in the PA stage of either unit. The BS170 runs barely warm to the touch (tip of little-finger - thermometer!!!.)
The second MCU/EEPROM just has "crud" in the programmable parts of the menu entries. It came straight up to Run, instead of entering "Diagnostic" cycle at first power-on. - it cannot be reset? and I can't reprogram memories. If new entries are put in, they are lost when "loaded." It has been like this from the start.
The two units stopped operating at different times - ie: as they were commissioned.. There is no local explanation - storms, power surges, static, etc - they also were run from separate fixed, stable linear supplies not running any other equipment.
Is there a problem with the reliability of the MCU/EEPROMs, post-COVID???

ANY THOUGHTS, please. de Alan VK4AAN

?replace it by 2x IRF510 (better thermal resistance,?

Thermal resistance is the least of your problems. ? ?IRF510 is quite hard to drive and has a relatively large input capacitance so it has slow switching and it’s easy for that C to work with any L for overshoots and resonance and yes. Increased dissipation .

I don’t know how accurate my SWR meter is RW-20, but for an equivalent load I got the following readings

--
73, Oleh, UY2ZA

--
73, Oleh, UY2ZA

--
73, Oleh, UY2ZA

If you put the new capacitors where you say you put them , you will destroy the wave shaping built into the? Drain supply cct.??

So you may have the Fr spectrum management agency down on your head.? ?Separate PM sent to you? about a known good 100 V DS max ,? small Input C mosfet.?

Regards,? TEF

for those who wonder where the magic 80 R number representing the Z of two AC08 gates in // came from -?

as per PM to Felix?

Re? Simulation results for? a? 74Ac logic gate doing a direct drive into a low power mixer? that I just sent.?

The 80 R output Z which? I used for? AC08 logic WHEN IN a PAIR of two? is NOT a guess.? John Z told me of simulation model he is using that? has? 150 R per gate.??

I back calc'd the Zout? from a datasheet for that? part? (I think it was an ONsemi datasheet)? . You get two answers depending on whether sinking or sourcing.? The average Z for those cases is 192 R.

I therefore took the half way point for previous sims of 165 R per gate.??

I decided to just round this to? 160 R per gate for simplicity later on.? - So it is based on two indep sources of data.

The Z out is? taken outside the LTSpice signal source for the obvious reason that it has to change when gates are run as a paired gate,? at triple or whatever topology is used.by the? designer .

The more I use LTS,? The more impressed I am by how flexible it is and how robust it is .? It's amazing that it came out of the USA.? You'd expect something of this quality to be out of German universities or perhaps French .? I have zero respect for the current US technical education system,? Rien.?

BTW if you ever want to do tech translating use DeepL translator. I used that to translate put the? Qcx mini manual into French and then did some hand editing to do a tidy up in the process? .? I did an improved version of the manual with all the English in the back end removed and a cleaner parts list but Hans never loaded it to the web page .? I guess he's too busy.?

I believe the order listed as #1 on the list is what is next up for production and shipping. It’s noted on the QMX product page they are producing and shipping around 25 units per day so to get an estimate of shipping time frame I believe you could find your order# on the list and dived your order position# by 25 for a rough estimate on the number of days until your order is up to #1 on the list which would be next in line for production and shipping. At least that’s how I interpret the list.?