I have completed building and tweaking the QMX Rev 2 for 80-20m. It seems to be functioning correctly, with some minor bugs. Great Rx and Tx, everything seems within acceptable ranges as analyzed through the diagnostics terminal.

My problem is that the left rotary encoder, when turned in either direction only raises the volume. I have submitted a ticket to support with a brief description of the issue. A factory reset returns the volume to the default level. There is continuity between all 5 pins and the top of the board. Continuity between the 8 male header pins on the controls board and the 8 female header pins on the main board. The right rotary encoder functions correctly. 4 of the 5 pins of the rotary encoders each have continuity to one of the female header pins on the controls board.

Everything else works great. Some bugs I noticed, which may have been mentioned before.

Changing from USB to LSB via the menu changes nothing.
The right rotary encoder is unresponsive for the first counter clockwise click.
Tuning in 1 MHZ steps below 3 MHZ locks up the unit and a hard power cycle is required.

Hopefully it is just a faulty part and not a new issue.

A final question, would cheapo ebay 1N34A diodes be ok for the new "QMX Rev2 Issue Modification"?

Thanks to all of you, a great community. I tightened up my inductor windings on L513 to get better power out on 20m. Also tightened up L401 to center the filters in the bands. I might try the extra parallel capacitance to resonate 80m better, although tightening L401 helped a bit.

Thanks again, having lots of fun despite no volume control.

73 Brandon K9PZ

Hi Brandon

Almost the same situation for me but on the right encoder and tactile button. See my post on Jan 6th.
I don't think the encoder is faulty because it works but the diagnostic reports its action on the left side.
Very strange bug !

Best 73 de I1MDQ Nino

Nino,

Thank you for your response. All buttons work correctly for me, except the left encoder when turned either direction only raises the volume. I updated the firmware again, nothing changed. I am going to switch the encoders on the controls board when i get more time, that should tell me for sure if i have a hardware or software issue.

73 k9pz

Hi Brandon,

Today I replaced the right encoder and the situation is still the same. In my opinion, it is not a hardware problem. Perhaps there should be something wrong with the board or the firmware. I'm at a dead point then I prefer to leave it until I know more or maybe a new firmware release will solve the problem.

Best 73 de I1MDQ Nino

开云体育

Hi Nino, Brandon--

Some random responses on my part:

• I too have noticed that, when the frequency goes too far up or down, it gets "stuck" and requires a power cycle. Reported to Hans.
• SSB hasn't been implemented yet, so it might not honor the sideband. BUT I know that I've been able to set the sideband for LSB on 80 (version 12 firmware)... So there may be something else at play, here.
• Haven't noticed what you (Brandon) reported about first CCW click, but maybe?
  

Nino-- Given that the right encoder works well for "everyone" else, it's hard to see how that could be a firmware problem...

There are several functions attached to the right encoder. Turning it should change the frequency. Clicking the button should invoke rate or select message. Do any of those functions work?

Looks to me like the MPU is sensing which switch is activated by sensing the resistance of the connection (JP302-6 to ground). You don't mention how the right hand encoder is malfunctioning--I'd suggest checking for solder bridges between pins on JP302. Consider that the problem with the right hand button and the right hand encoder might be somehow connected...

Wishing you luck!

73, Paul -- AI7JR

Hi Brandon,

Today I replaced the right encoder and the situation is still the same. In my opinion, it is not a hardware problem. Perhaps there should be something wrong with the board or the firmware. I'm at a dead point then I prefer to leave it until I know more or maybe a new firmware release will solve the problem.

Best 73 de I1MDQ Nino

-- 
Paul -- AI7JR

Paul - the CCW seems to have resolved itsself. Maybe I was seeing ghosts.

I swapped the encoders and as before the right side functions correctly. Now turning the left side is unresponsive in either direction. Pushing down on it works as before, this was verified in the terminal diagnostics. There are no shorts to the encoder body.
I am at a loss now.
Seems as Nino stated a firmware or controls board issue. At least i can't accidently crank the volume too high now.

I will give it another very fine look over. Odd that the problem changed slightly by swapping the encoders.

Cest la vie

73 k9pz

开云体育

Hmmm... That it moves with the encoder, is rather incriminating of the encoder...

Did you say that you've replaced the encoder once?

You might check that the switches on the encoder are opening and closing properly.

Paul

Paul - the CCW seems to have resolved itsself. Maybe I was seeing ghosts.

I swapped the encoders and as before the right side functions correctly. Now turning the left side is unresponsive in either direction. Pushing down on it works as before, this was verified in the terminal diagnostics. There are no shorts to the encoder body.
I am at a loss now.
Seems as Nino stated a firmware or controls board issue. At least i can't accidently crank the volume too high now.

I will give it another very fine look over. Odd that the problem changed slightly by swapping the encoders.

Cest la vie

73 k9pz

-- 
Paul -- AI7JR

The original problem has resurfaced. It did not move with the encoders. I put the left encoder in place of the right, and right in place of the left. After this, initially turning the left encoder either direction was unresponsive. This behavior was duplicated in the diagnostic terminal.

After a power cycle the original problem of the left encoder only increasing volume has resurfaced, the diagnostic terminal agrees, and this is after swapping encoders.
No new encoders, just the two that came with the kit. All other buttons and encoder functions work fine. Great rx and tx.

73 k9pz

开云体育

Have you done a Factory Reset yet? What version of firmware are you running?

(If you have done the reset, don't think there's any point in doing it again...)

Paul

Hi, thanks to all !
I have already checked carefully the continuity on the main board between the connector and the MCU (pins 31-91-92-93) and all is fine. Now I will try to bypass
the control board plug-in connection and wire temporarily a direct connection between the control board and the main board. However, if this attempt fails, I will be again in the dark !
Best 73 de I1MDQ

Nino,
What Hans says makes sense. Here is one of the other possibilities he alluded to.?

I repaired a friend's QCX+ with similar issues with his encoder and push buttons. There were two faults. One fault was an incorrect resistor (corresponding to R301-R303 on the QMX Plug-in Controls Board) causing a button push not to work. In this case the resistor value was very different from its marked value.?

Of course, there are no resistors in the encoder S301 and S304 rotary controller switches lines. In the rig I repaired there also was a trace cut in one of those lines. So in addition to bad solder joints and shorts, there are a few other possibilities.?

An ohmmeter (with the rig powered down) allowed me to find both of those faults.?

- Dan
NM3A

Hi Daniel

Thanks for your information but I can't still find the fault. I have very carefully checked all connections of the control board and performed an accurate continuity test and all
is fine. Continuity between control board parts and connector outside pins is OK. For now, I can only suspect something wrong with the main board (maybe some faulty part) because I can't think of any other possible issue. The right encoder button and the right tactile button when pushed don't activate the right firmware function and both cause the need to cycle the power because the shut-down function becomes inactive. I have built successfully many kits including QCX ,QCX plus, and others even more complicated but I'm now really at a dead end. It is a pity because all tests went well, and TX power and RX are within an acceptable range meeting the required expectations but this problem makes the QMX almost useless for the moment.

Best 73 de I1MDQ Nino

Thank you sir. Your support and patience is greatly appreciated. I am going to trace everything back using the schematic and resolder. I got in a hurry close to end.

Going to take my time and triple check everything.

73 k9pz

Nino,
Sorry that it still doesn't work properly. My suggestion is to find someone else (local ham - in your local club, maybe) to look at it. A fresh approach may turn something up. Good luck!
--
73, Dan? NM3A
There are moments when everything turns out right .... Don't let them alarm you; they pass.?

-Jules Renard

Hi Bruce

Thanks for your assistance. I have measured the voltage and I can't get the expected voltage while the buttons are pressed. The only correct voltage I get is with no buttons pressed. However, I have already measured the grounding between connectors, buttons, and encoders and I have a continuity. To what grounding do you refer exactly?
I have carefully soldered all components applying a lot of heat as recommended. Anyway, I can't get the indicated voltage if I push the buttons.
It seems very hard to identify the problem.

Best 73 de I1MDQ Nino

Hi Bruce

Once again I'm puzzled ! Apart from wrong voltages why the diagnostic result gives always left even if I push the right buttons ??

Best 73 de I1MDQ Nino

开云体育

:-) That's precisely what you want to investigate! ;-)

I think it can be safely said that the connections and values on your unit do not correspond to the published QMX schematic.

When we're dealing with an ECB (that works for others, e.g., no known ECB wiring mistakes), that leaves

• Unintentional short circuits (solder bridges)
  
• Defective components
  
• Open circuits (cold solder joints, broken traces and defective vias, on the ECB)

"Apart from wrong voltages why the diagnostic result gives always left even if I push the right buttons ?"

These are good questions. On the schematic, pressing the left, right, or tuning click closes a circuit with a different valued resistor for each one. Measure those resistors, looks like they are in the wrong locations! Fix those first, and the rest might make more sense!

Good Luck!

73, Paul -- AI7JR

Hi Bruce

Once again I'm puzzled ! Apart from wrong voltages why the diagnostic result gives always left even if I push the right buttons ??

Best 73 de I1MDQ Nino

-- 
Paul -- AI7JR

Well Hans was right. Who would have guessed?

After resoldering and retesting everything and chasing the schematic backwards from the left encoder, i encountered two faults.

#1 The bottom left pin of the left encoder grounded out when connected to the controls board.

#2 the bottom right pin of the left encoder had no continuity what so ever to the 2nd from the bottom right pin of the 2x4 header.

#1 solution was to disconnect the bottom left pin of the left encoder bypassing the contact on the controls board, then installing a jumper to the the bottom right pin on the 2x4 header.

Solution #2 was creating a jumper from the bottom right pin of the left encoder to the 2nd from bottom right pin on the 2x4 header, the encoder pin remains connected to the controls board because it was not grounded out.

This in effect created new traces that i probably destroyed by being too rough when clipping off the excess length of the header pins. Its a mess, but it works great.

Nino, i wonder if you damaged your controls board as well?

My continuity varied enough to convince me everything was ok. The connections were intermittent, very tricky. Only using the schematic was i able to find the faults.

Thank you for all the help everyone. Becareful clipping those thick pins! I recall Hans making a point of this this in his tips video. I still screwed it up! She's not pretty, but she works.!

73 k9pz