Re: QMX pre-assembly USB-C question
I went ahead and reflowed the USB-C connector per Hans' 52 tips video. Picture of my reworked connector. I also fixed the Q103/Q104 short in about 1 minute with a hot air rework station.
--n1bs
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On Fri, Sep 1, 2023 at 3:24?PM Brian Swann n1bs < n1bs@...> wrote: I was inspecting my board set before beginning assembly. This is my USB-C connector. I can see there is a little bit of solder in just about every hole, but should I be touching these up? Seems a little sparse. I don't want to cause more problems than I might be trying to solve.?
Also, unrelated, mine has the Q103 / Q104 short, shipped 8/24/23.
Brian? n1bs
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Re: QDX - protection of BS17O PA
My apologies, in my last post I said? "BS150" when the correct part is "BS170".
a BIG Thank You to all who responded with diagrams, diode part numbers, etc....!
I have the required diodes in my Bench Stock, so will implement the change this weekend on all four of my WSPR QCX-Minis...
Appreciate the Help!!??
Brian, AA5H
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Re: QMX pre-assembly USB-C question
I would just dab a bit of liquid rosin on them and touch them with a soldering iron and maybe the slightest tap of molten solder on each one. They will wick the solder down in to the connector via capillary action.
If you do not have a desoldering tool or the technique you can mess up a pad or delaminate the trace from the PCB.
Those grounding ears on either side are important to get soldered down. That is the mechanical rigidity of the USB connector and every time you bump the external USB cable you are putting stress on the connector. I have a $2000 laptop that is junk because the USB-C connector tore off that way.
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Tisha Hayes, AA4HA
Sr Engineer, 4RF Inc.
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Hey I recently built the 40M QCX-mini, and followed the instructions to a T(1). I took my time with the winding, was very neat and tidy, and I get 4.6 Watts out (13.6V), measured on a QRP Guys QRP power meter kit.? No modifications were necessary to the windings, and maybe there are nominal gains to be had by fussing with the toroids, but I think I'm good.? One trick I saw was using a bamboo chopstick (clamped in a small vise or vise grips) to hold the toroid while you sew (and count) the loops through the doughnut. I used a small paintbrush, but it freed up both hands for fiddly work.?? Now I just need proficiency in CW! HTH Todd KE7AJZ --
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Re: #QMX #BPF problems with fault finding
#qmx
#bpf
Check the voltage at C406, should be about 2.5v (other end is at ground).
-mike/w1mt
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Re: QMX won't power off and odd voltages on Q103
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Dear members,
I found some on line and ordered them.?? They should be here soon.?? I will have extras when they get here so if anyone else
needs a SMD 0805 47uH inductor please let me know.?? I am willing to share and I will have quite a few extras.
--
73 Dave WA5DJJ SUPER GRABBER WEBSITE:
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Dear Chuck,
I needed the surface mount part.... I found them on line and am waiting for delivery of 200... I think there will be an offer from me to
get rid of some them here soon.? Thanks for looking.
73 Dave
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Re: #QMX #BPF problems with fault finding
#qmx
#bpf
Hi Mike,
unfortunately Factory Reset did not change things at all.
If I receive signal on my main rig at S7 or higher I can hear station on QMX, however if it is S3-4 there is no signal on QMX.
---------------------------------
73 de Marek SP9TKW
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Re: QMX pre-assembly USB-C question
Yes. Ideally remove the existing solder (solder sucker?) and then fill those holes all the way down to the pins on the physical connector.
73, Willie N1JBJ
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On Sep 1, 2023, at 3:23 PM, Brian Swann n1bs <n1bs@...> wrote:
I was inspecting my board set before beginning assembly. This is my USB-C connector. I can see there is a little bit of solder in just about every hole, but should I be touching these up? Seems a little sparse. I don't want to cause more problems than I might be trying to solve.
Also, unrelated, mine has the Q103 / Q104 short, shipped 8/24/23.
Brian
n1bs
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QMX pre-assembly USB-C question
I was inspecting my board set before beginning assembly. This is my USB-C connector. I can see there is a little bit of solder in just about every hole, but should I be touching these up? Seems a little sparse. I don't want to cause more problems than I might be trying to solve.?
Also, unrelated, mine has the Q103 / Q104 short, shipped 8/24/23.
Brian? n1bs
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Hi,
what I think it would further improve the functionality is:
- an AGC ( fast or medium one) for the CW?reception (already mentioned elsewhere),
- if?the volume control would followed a logarithmic law rather than a linear one (smaller steps at lower volume).
73 Bojan S53DZ
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Re: QMX won't power off and odd voltages on Q103
Hi Kees
Remember also that we do test the USB connection of all boards here before shipping. The recommendation to add a bit more solder is more about long life. Since it doesn't intuitively look that secure even if there definitely is an electrical connection.? 73 Hans G0UPL
On Thu, Aug 31, 2023 at 07:53 PM, PHILIP GRAITCER wrote:
D103 ? 2.426 when unit on instead of -3.3V ?as you suggested.
Grounding the 78M33 (middle pin) turns the unit off
Phil,
The output of D103 should be "approximately" 3.3V (that's not a minus sign) and 2.426V is way on the low side. Grounding the LIN_REG_EN pin and turning the 78M33 OFF is good. Does it stay OFF when you remove the grounding ? That would indicate control had been handed to the processor and it enabled the 3.3V SMPS.
Speaking of firmware and loading new firmware have you reloaded the latest code AND checked the USB-C connector for good solid connections.?Hans recently released video (52 things....) shows relatively good soldering on the 16 USB-C connector pins but there are apparently a number of boards out there which are not nearly as well soldered and have "iffy" connections. I have posted details in other threads. The reason I call it an "iffy" connection is because the GCT USB4085 connector has 62mil length pins and the board is about 62mils thick. The pins also measure 0.15mm x 0.22mm and the plated via hole is 0.40mm+/-. That's not like "a BB in a rain barrel" but it does indicate good solder wicking between the pin and the via barrel is required. Since soldering those 16 pins is very difficult for the manufacturing facility it generally picks up a little solder from the via barrel plating ......but many times there is too much space between the via barrel and the pin. The result is poor or no electrical contact. Fortunately the 16pin USB-C connector is "reversible" and there are 2 pins for each signal which Hans wired together on the artwork ....so the chances of making a "good connection" are better but not 100%. Sure hope I didn't confuse anyone more.... just trying to help.
73 Kees K5BCQ
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Got it.? Thanks.? Wasn't aware the inputs worked like that.??
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Re: QDX - protection of BS17O PA
After my QDX's finals bit the dust due to the remote ATU doing a re-tune cycle during transmit, I added some simple VSWR protection devices like shown. These devices are just something I had in my junk parts bins.
I can now transmit without an antenna connected and not destroy the finals. Output spectra was not affected and meets current FCC limits for spurious emissions.
A voltage-clamping diode has been on every <= 5W solid-state QRP rig since .. the 70s? Cheap insurance.
--- Zach
N0ZGO
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Re: GPS disciplined oscillator.
On 01/09/2023 13:46, Hans Summers wrote: There should not be any 0.5 Hz frequency modulation. Hans, I posted this screenshot back in March, no-one has responded with their own close-in spectrum. The picture shows the effect of removing the PPS. I did try at least two ways of powering the Progrock and attaching/feeding the PPS. I accept it may still be some silly thing I did or the way I tested. 73 Alan G4ZFQ On Fri, Sep 1, 2023 at 4:36?PM Alan G4ZFQ <alan4alan@... <mailto:alan4alan@...>> wrote:
> I'm wondering if I can use the Progrock2 with the QLG2 to form a GPS
> disciplined oscillator that I can use with my Adalm Pluto requiring
> 40MHz local oscillator?
Roger,
My tests indicated that the PPS modulates the output.
Just a little +/- 0.5Hz, but I'd be wary to use it for a reference.
I have just left it, no further checks, there have been a few other
reports that have not mentioned that, maybe not noticed or not present?
Or, just bad connections?
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From formula X = (14,050500 X 27,004,000) / 14,052,400 = 27,000,349
(Freq displayed / Frequency measured) = (X / Current Reference Frequency setting)
If the result is that you are even further away from the desired frequency, then invert the part to the right of the "=" sign. I sometimes get it upside down on the first try :)...... Good luck
Ron,?
I failed to ask in the last post... how did you derive that value to set?
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Hi Glenn. I've built and/or repaired several of the 40 meter QCX variants and have not seen one take more or less than the prescribed number of turns on the large winding of T1. You should be fine winding it as designed. The 80 Meter version usually requires some turns?adjustments due to the large number of windings and the necessity of scramble winding it to get all the wire on. One thing .. .If you do decide to go ahead with extra windings anyway, it might be wise to solder the ungrounded end to the top side of the through hole to make it easier to remove for sinding count changes, without causing board damage. You don't need to clean out the hole when ready to do the final connection either. Just heat it to melt the solder and push the wire through. Or just leave it soldered to the top pad. It's a good connection through to the bottom of the board either way. Good luck ... Ron
Hi all,
I am just about to commence my very first QCX mini build and I just want to get the community's thoughts on what I am considering in doing for winding T1 for the 40 metre band.
I am a little concerned that if I wind 38 turns for the third secondary that it may be necessary to add more turns in the alignment steps to get it tunned. My thinking is that it will be easier to remove turns than to add, that I should consider winding 43 turns instead and have the possibility that I will have to remove turns.
So my question to the community is how common is it that constructors need to add turns to the standard 38 turn winding for S3? How common is it that turns need to be removed from the standard 38 turns?
Many thanks,
Glenn VK2AXV.? ??
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No stress Hans, 100% understood re your todo list ?
73
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Oops, never mind, I can't read.? Didn't notice that there are both SMD and axial 47uH ones.
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Cheers,
Chuck
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Tisha Hayes, AA4HA
Todd Schlemmer
Marek SP9TKW
Ronald Taylor