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I have this exact same one on recommendation (I have the USB version) , but it appears that the QMX+ needs more. The radio turns on just fine, but when trying to transmit, it just thumps; no cw. I’m wondering if I get the 6000 if that will fix that.?

OR, if the Bioenno BLF-0906W (9V, 6 Ah) that I ordered last night will work. I’m just trying to get the radio up and going. Right now, it’s a beautiful paper weight. ?

I meant to say:

1. can I power a 12V QMX+ with a Bioenno *9V* 3ah battery?

sorry for not being clear. ?

Look at the build manual for the QDX-M...it has jumper configurations there. Now that I see Jeff's comment....it brought back a memory......I had some weirdness once like Jeff mentioned on initial startup of a QDX I built....and I messed around with jumpers for a bit before it suddenly was correct.... I think Jeff's right, there's a firmware/startup bug in there somewhere.?

-Nate
N8BTR

I have not done any jumper troubleshooting yet.? Until I figure out where the jumper should go in the first place, I'm still status quo here.??

If someone could tell me where the jumper should go to "trick" the firmware back to normal 20-80 that would be fantastic.

Let me look at the build manual.? Can you explain where I would be putting the jumper?? This is a 20-80m QDX.

Correct is "no wire" for 80-20m.

Greg, sorry to read about the damage.
But you could check now the gate waveforms without working BS170. (Of course the gate capacity is "working".) Now there is no possible feedback from drain current to the gate circuit.

From my post before:

The voltage is >= 1V for around 70% of the period. The part of the waveform with voltage around 1 V is wrong.

It would be interesting to know if the input duty cycle of IC503 is equal to the wrong output duty cycle. But maybe without drain voltage the wrong duty cycle is not wrong anymore?

73 Ludwig

Rick,

I use a TalentCell YB1203000 LiIon battery. It puts out 12V when fully charged. It's the same size as the original QMX. It even comes with a cable that fits the QMX. And it lasts for many hours. It has worked great for me. (Mine came without the USB port.)

Hi Rick,

1. A fully charged 12V LiFePo4 pack has a voltage of about 14V which might be too much for a QMX(+) when the SWR is too high (although I've powered my QMX with the exact same setup in the past)
2. Have a look at the Talentcell Powerbanks. They come in a 3A and a 6A version and provide 12V output and some USB ports.
3. Absolutely! I've been using the ATU-10 with my QMX transceivers for quite some time now.

Hope that helps!
73,

Simon

Hi Ludwig.? Thank you for the analysis.? To answer your first 3 questions:
The GND lead was clipped to the bnc output connector
The ground lead is approx 150mm
The original BS170's are in circuit.
Unfortunately while looking for the waveforms you asked for, I must have shorted the +ve at the BS170's as they have no Drain voltage so I think Q507 has been destroyed as there is 11.5V on its Source, nearly 11.5V on its Gate and 0V on its Drain.? So at this stage I have ordered a replacement AOD403 from Digikey and it will probably take a week or so to be delivered.
Thank you for your help to date and I will update when I have replaced the AOD403.
Regards
Greg

Hi all,

I’m new here, so forgive me if this has bern hashed. I have a 12V QMX+ and want to get a battery for portable operations. I asked this question on the Facebook group and ?got responses that I need to do diodes or buck converter to keep the voltage no more than 12V per the instructions.

As I am handicapped and have poor eyesight as well as shaking, I cannot build anything and look for pre-made items . My questions are:

1. can I power a 12V QMX+ with a Bioenno 3ah battery?

2. what off-the-shelf 12V batteries would work with my QMX+?

3. can i run an ATU-10 qrp autotuner with the QMX+?

?Thanks for any responses.

72 de AI3W, Rick

FT8 with FT8CN

Peter HB9EBE

QCX-Mini?

FT8 with iFTX

Still working on my 3.3V SMPS.? Maybe I see the real cause now.

Resistance from the + side of C106 to the cathode side of D107?



240k in one direction, 60K in the other direction.? ?The resistance reading varied quite a bit, probably because of the capacitance of C106
I also took the reading on the pads of L102.? I got similar results.? Harder to get to, so I wanted to make sure my readings were correct.

I would expect that L102 would have a much much lower resistance.? The wire does not look THAT thin.

Just noticed an identical inductor on the other power supply.? It is 2-3 ohms.

That would explain why the switcher side of this board is not working.

I have an order in for a replacement SMPS boards, but I have no idea how long that order will take.? It has not yet shipped.

Anyone know of a good source for a replacement part for this.? Digikey CD54 series only goes up to 220 uH.

Thanks,
Mark

To Warren and Mike and anyone else who may be able to help.

I changed the bpf config for 40m from 3 to 2.? The noise level dropped substantially, but i still do not hear 40m signals.

I then took a jumper and applied it to both legs of c402.? When I did this all the noise went away and rig is dead silent except for microphonics.

I am not sure where to go.? Extremely high noise on 40m and no signals.??

I did re-update the firmware 1.0.19.? Still no luck.? I did attach a pic of the suspect area of the board as well.? Thanks for any assistance you can provide.

My QMX+ is working in transmit now fine with help from Jeffrey:)

However the receiver is still dead.?
Turn on my QMX+ and I get noise, and it fades out within a few seconds!

Just ordered two PCM1804's and will bring the PCB to work and install it.

???? pin 14 measures 1.49K Ohms
???? pin 22 seems low at 314 Ohms, so I willing to bet the IC is defective!

Michael N2ZDB

This is a 6aH LiFePO4 battery with regulated 9v output.

Mine registers 9.3v until the battery is dead, lasts around 12 hours of 4.5w FT8.