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My QMX transmit is broken with or without the amp Settings are (and were) as per your notes (transmit & 5V PTT enabled for each band). I have no idea why or how the amp killed the QMX since it works

Jamie, we are both correct!? There are at least 2 versions of the schematic, one uses Q4 and one uses T1. I hope all goes well with your surgery.? Check this thread when you are back among the

I think I'm ready to give up. :( In trying to diagnose the above questions, I powered it on and the magic smoke come out of the BS170s.? I ordered more, carefully replaced them, and again the magic

The wiki page QMX QMX_plus Startup ( /g/QRPLabs/wiki/36878/221022 ) has been updated by @Ludwig_DH8WN <DH8WN@...>. Compare Revisions (

I suggest only troubleshooting this with no DC applied. Use ohmmeter. See if L503 has continuity. If yes, it is likely okay. See then if you shorted something else. Curt

I’ve looked at those voltages and IC403 pin2 to ground shows 0.015V and pin 14 to ground shows 0V on IC405 all the voltages line up with what you’re saying they should be but on IC406 I’m

Trying to add the image again...

I forgot the first rule of radios - if something works, don't fix it. Anyway, I wanted to replace the diode that I have been using for the Rev 2 board modification with a smaller diode.? I replaced

That's interesting. I feel the opposite about my QCX Mini compared to the QMX. The QMX Mini receiver sounds better to my ears. Maybe once Hans gets around to eliminating all the SMPS-induced birdies,

Hi Scott. That usually happens when you install a blank IC2 without the EEPROM file loaded. I suspect something happened to IC2 when it was shorted. The easiest fix is to order a new firmware chip

The other factor in all of this is the plastic package design. The heat sink practice for those other styles won't necessarily work here. The qmx design takes all this into account. Many cw qrp

A number of examples have shown BS170s blown apart. But is that due to overheating in service or a result of a high voltage causing one to short THEN blow? 73 Alan G4ZFQ

So, as a bit more information (not all of it, obviously as you need to be security cleared for that!) I was thinking more of mainly increasing the thermal mass a little and perhaps trying to couple it

Very interesting, Jim ! I believe you meant Q4 and not T1, that is the base of the ‘3904. And so removing C1 is also advised (or lifting one leg). I believe there are 1/8” jacks that can be wired

Hi all, My Dad just finished his QMX-mini build and after adjustments,(before casing) accidentally laid it on a spiral notebook and shorted something out. Now he gets the message “Use original

And that's with the QMX+. I don't hear it at all with my QMX HB. -- 73, Dan - W2DLC

Don, I've gone back to 027, but when I was experimenting with the 003 beta, I could hear a tone on 12 meters the strongest, then 11 meters, 10 meters not as strong because the noise level is higher,

Hi, After the installation of the latest Beta, the LCD shows only processing. Is this normal? Few minutes later i un/replugged the powersupply and it works as expected, ok, a little bit better

Hello Hans, I would like to respond to your concerns one at a time

Lundi = French for Monday?? Jack, W8TEE