开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. QRPLabs
  2. Topics

QMX Plus Build Comments

 

Here are a few comments on my recent QMX+ build that may be of use to others (References are to Assembly Manual Rev. 2.00):
?
1)? More heat, less solder.? As mentioned in the Assembly Manual the six layer circuit board requires more heat than previous boards with fewer layers.? But more heat does not mean more solder - I found myself having to wick away excess solder from some pads until I got the hang of it.? I try to scrape the enamel off the inductor leads instead of burning it off, but still these were challenging to manage the heat and solder amount.? I used a slightly larger iron (25 watts) on the QMX+ than I usually use and installed a new pointed tip.? When soldering I tried to hold the iron nearly vertical to avoid heating other components and pads.
2)? Assembly Manual page 34:? I used an electric drill to twist the three wires for T401, it enables a tight and even twist.
3) ?Assembly Manual page 38:? To hold the 3.5 mm jacks straight while soldering I used a .125 inch drill bit (dull end) inserted into the jack as a lever to pull against to ensure correct alignment.
4) ?Assembly Manual page 47-48:? As the manual says, the last nylon requires a lot of patience and good needle nose pliers to turn it onto the screw thread.
5) ?Assembly Manual page 49, Step 10:? Soldering the sixteen pin header under the front panel is challenging.? For this I used a smaller iron having failed the first time to achieve good connections.? This error resulted in a dead LCD display and other frustrations when I first powered up the QMX+.
6)? Software Installation:? Initially I was unable to install the software per the instructions.? Having a dead LCD display further complicated the issue.? It turned out that Version 27 software was already installed on my unit and the QMX+ did not go into Firmware Installation mode on power up.? I soldered short wires to the circuit board in the AUX2 and GND pads so I could force it using a clip lead.? That was when I discovered the software was already loaded.? Following that, I inspected the board for any errors and resoldered the front panel sixteen pin header.? The unit came up and is working fine.
?
I'd like to thank Hans and his team for a fantastic kit - all the parts were there and the instructions are marvelous!? Good luck on your next build!
?
Jim? K7WA
?
?
 

Jim,
I agree with all of your comments.? I, too, was a little?frustrated with?the firmware upload process until I realized it was already loaded.

I used a 60 Watt iron and filed?down the point to make it even pointier.? I used very fine solder and waited 5 seconds for the pad to heat up before giving it he fist dab of solder.? And, like you, I did need to wick the solder and start over a couple of times.??

I installed the read panel connectors with the panel held in place by the BNC and some blue masking tape.? The GPS connector was the hardest to get aligned.? I could not get the front two 3.5mm connectors exactly square to the sub-board, but they are close enough.

I usually use the scraping method with toroid wires, but this time I used the solder-blob method with a little scraping to get the black?gunk off.??

The lpf toroids sit on the board at a small angle, not exactly square as per the printed guides.? Don't try to correct this.

I stopped whenever I got tired, especially during all the winding.? It took me a week of 3 hours on average per day.? Really enjoyed it.? It's been a while since I built a kit with through-hole components and toroids. I think the last one was my K2, which is still a daily-driver.

73, Glen W6GJB

1 - 2 of 2