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Re: Error in 5V SMPS diagnostics
Hi all The firmware reports an error if the duty cycle is higher than the internal model's maximum for the applied input voltage, in the attempt to raise the supply rails (3.3V and 5V) to their target values.? If you apply external?3.3V and 5V linear supplies for some reason (not recommended) then the situation depends on whether the processor measures the voltage?as above or below 5V (or 3.3V in the case of the 3.3V supply rail). Since the exact values depend on component tolerances, if you do nothing but build it as is, it may work, or it may not, depending which direction the component tolerances lean in, in your particular case. The PWM duty cycle will either be zero (if the linear supplied voltage is measured as over 5V) or maximum (if the linear supplied voltage is below 5V) because essentially the system has become open loop. You are forcing the output (the supply rails) to a particular value but the control loop now has no control over it, but it doesn't know it has no control over it and is still trying.? The correct solution is to place a 100K resistor in parallel to R112 (3.3V supply) or R113 (5V supply) in which case when the rails are at 3.3V and 5V respectively, the microcontroller will always measure them as higher than they really are, so will think that they are too high, and will reduce the PWM duty cycle to zero and not cause any error.? 73 Hans G0UPL On Mon, Nov 18, 2024 at 3:43?PM Dave (G8PTN) via <daveg8ptn=[email protected]> wrote:
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Re: Error in 5V SMPS diagnostics
Hi Chris,
I am not sure what the criteria is for the ¡°Error¡± status on the SMPS, perhaps it is measured voltage and duty cycle. It does seem a bit odd that the 3V3 supply does not report the error even though Duty cycle = Duty max. ?
Anyway, the change seems valid.
Assuming the reported voltage on the PUTTY screen = 2 x ADC_5V, the calculated VCC voltage is the same for both of your arrangements. In the case with the parallel 220k, it stops the ¡°Error¡± state and the PWM signal should be turned off.
General equation:
VCC = (PUTTY_V / 2) x (1 + R2/R3)
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Without the parallel 220k:
VCC = 4.99/2 x (1 + 22k/22k) = 4.99 V ?
With the parallel 220k:
VCC = 5.24/2 x (1 + 20k/22k) = 5.00 V (VCC is at the same voltage, but the firmware will calculate 5.24V as you have shown) ?
As you say, ?perhaps forcing the PWM signal off is advantageous, but I suspect if the firmware thinks the voltage is too high, the status may also show an ¡°Error¡±.
73, Dave |
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Re: MFJ-1984LP Antenna 80m-10m EFHW 30W
Good day
?
?the setup I¡¯ve seen has the coil about 6ft from the transformer. 6-7 turns on 1 inch form. ?This should pull upper bands down into CW portions nicely.?
take a look at the ¡°my antennas ¡° brand of EFHW available I believe they show this. There are also some YouTube videos by an N4 call that shows how to do the coil.?
several others for sure. I guess it originally came from a German antenna book?? Not sure on that. But it works! ?Good luck. Sorry I don¡¯t have more specifics. I¡¯m on the move but figured I¡¯d send along what I could remember. I¡¯m sure someone will be along who will fill in more blanks or correct me :).? |
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Re: Is it bricked?
#dummy
#firmware
#problem
#QMXplus
#troubleshoot
It doesn't seem to be bricked because the MCU is running well enough to connect to the PC as a drive.
I would try PUTTY.? There are guides about this in the manuals. but basically
The lack of a display may be because of something else but the diagnostic screen in particular should help you (and us) find out what is happening.
Once we know what's happening there's a better chance of fixing it, a lot better than guessing.
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BTW the 1.65V you measured is half the 3.3V power supply which is supplied on a different pin (ADC_3V3) It's supposed to be that.
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
Dirk,
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I definitely did not miss your report. Just wanted to clarify it¡¯s material implications.
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This is my understanding:
1.Reset function of ATU works as expected, putting ATU in a bypass mode when autotune is off.
2.Bypass function of ATU is less critical for this project as though before.
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Please correct me if I¡¯am wrong.
-- 73, Sardar (AC8L, 4K6SA, VA3DUA). |
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Not better, debatable. Pushing?and holding the tune knob has an existing function... The proposed function on the speed is better because it does not involve any debate! 73 Hans G0UPL On Mon, Nov 18, 2024 at 1:33?PM Muhsin TA1MHS via <muhsin.dogrular=[email protected]> wrote:
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Re: MFJ-1984LP Antenna 80m-10m EFHW 30W
Good to hear that all works for you. Does your antenna has small coil about 72" from transformer? If so, could you tell me how many turns does it have? Also how high is your transformer above the ground?
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I am trying to setup mine (home brew) but I have problem to get low SWR on 10m band at CW portion of the band.
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Thanks for your help.
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--------------------------------- 73 de Marek SP9TKW |
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Re: Error in 5V SMPS diagnostics
Fixed.? All I did was add a 220k resistor in parallel to the 22k on the high side of the voltage divider that provides the ADC_5V signal.
The 5V SMPS Status is now OK, Voltage: 5.24V, Duty Max: 78%, Duty Cycle 0%.
The 3.3V SMPS still has Duty Max and Duty Cycle at 51% but that seems OK.
220k may be a bit low, 470 or maybe more would reduce the indicated voltage and might cause the duty cycle to be in range, although having it at zero for both could reduce the switching noise.
Here's the schematic.
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Re: MFJ-1984LP Antenna 80m-10m EFHW 30W
On Mon, Nov 18, 2024 at 2:20?AM dd5nt via <dd5nt=[email protected]> wrote:
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
On Sun, Nov 17, 2024 at 09:13 PM, Gwen Patton wrote:
I hope you all work this thing out, because I really want one of these for my QMX+. I just have no idea what you're saying.Hi Gwen, ?
My +ABS addition is working very well in my QMX+ after the tweaks we've all been discovering and developing here. I hope to validate Sardar's latest changes to the Companion Board PCB in time to confirm them and shop for some sweet JLCPCB Black Friday PCB promotions for the group's builds. I ordered the minimum 5 test boards tonight.
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If you'd like to do a build and fill all that empty space in your QMX+ case with some useful well-integrated enhancements, please send me an email at my ARRL forwarding address and I'll put you on my list and reply to you. It's the usual ARRL forwarding email address format (<my callsign> AT arrl DOT net). The PCBs will come with pre-programmed PIC and ATmega chips but you'll have to study the thread, particularly back around three weeks ago when the bill of materials (BOM) is discussed and consult Sardar's github documents to buy your other parts. Or join up with others and pool your orders.
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73,
Cal (AD8Q) |
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Re: 50W PA for 17m
Hi Jared, ? I¡¯ve been building this kit for 10m. Some modifications are necessary to obtain good results on that band. But, for 17m, I believe you will obtain reasonably good results by just changing LPF values as you noted. The power output may be about 30W or a little less with 20V supply. If you would like to achieve 40W-50W, it would be necessary to change T1 ¨C T3 cores to #61 material. But, the increase is only a few dB and may not be worth the effort. ? The number of turns you noted for the toroids are the same as the 17m LPF I am using with this kit now. ? The only parts you need to purchase in addition to the kit are 2 pcs 100pF NP0/C0G capacitors. I am not sure whether the parts in your Amazon link are NP0/C0G type, though. ? 73, Aki, JO4MTH |
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
On Sun, Nov 17, 2024 at 10:42 PM, Dirk wrote:
Thanks, Dirk! Yes--I missed it. That makes sense. If all those relays had been powered-up, my antenna, which features under 3:1 SWR w/o a tuner throughout the entirety of ham HF and even 6m frequencies, would've gone through the roof! ?
Did you see the AT-100 EEPROM cells cheat sheet I posted a few posts back? /g/ATU100/attachment/2277/0/EEPROM-Cells%20Content-de_eng.pdf I think some of the codes don't work the way we thought they worked. The codes definitions are in the manual too:
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The one I don't understand is cell 09. Why would one wish to enable a check for maximum SWR, above which auto tuning will not occur? Maybe to preclude tuner and rig thrashing when forgetting to hook up one's antenna or forgetting to rotate the antenna coax switch correctly, resulting in a connection to an open or short to ground?
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09 ¡ª cell to set the maximum initial SWR value, when tuning occurs. Values are
specified in the format: the first number is the SWR integer part, the second number is the tenths. If the value is 0, the check is not performing and the tuning always works. The default is 0. ?
73,
Cal (AD8Q)
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Re: Erratic ADC/IQ sweeps
Could be either one.? You can measure which one with a signal generator and oscilloscope.? Use a signal generator that can put a sine wave into the antenna jack (around 3mVp-p to 10mVp-p), and an oscilloscope to measure at the inputs of the PCM1804.? For example, put a 14.100MHz 5mV sine wave in, tune your QMX to 14.100MHz in CW mode, and you should measure about a 50mV clean sine wave at each of the 4 differential inputs of the PCM1804 (there is a 10x gain through the op-amps just before the PCM1804).? If one of the differential pairs looks bad, then look back, likely to the trifilar transformer.? If they all look good, it is likely the PCM1804 that is bad.
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You can take this measurement at the PCM1804, pins 4 & 5 (inphase) and the corresponding 4th & 5th pins down on the other side of the chip (quadrature).? Alternately if it is easier, you can measure at the outputs of the op amps IC405 pins 1 & 7 (inphase) and IC406 pins 1 & 7 (quadrature).? If you have a 2-channel scope, you can measure inphase and quadrature at the same time and verify that they are 90 degrees offset.? But if you only have one channel, it is ok, because if they look like good sine waves at somewhere near the expected amplitude, they are likely also offset correctly (and you can see the offset in the diagnostic IQ scan test).
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Special note: Make sure that you unplug the paddle/key and/or put the QMX in practice mode before doing this measurement.? Because if you accidentally bump the key and transmit into your signal generator, it will likely destroy it.? Don't ask me how I know....
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Stan KC7XE |
Dirk
Marek SP9TKW
Sam Hanie
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