Has anyone found a custom case for this buck/boost converter please? (Or models with the same dimension)

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(I don't have a 3D printer)

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Thanks

Richard, I'm glad you found the BS170 problem.? They probably sent you the wrong type of transistor, since all BS170s in those type of packages have the same pinout.?

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I think the peak-to-peak voltage measurements that you made on the bands with high power (over 6W) probably have some measurement problem, since I don't think those voltages are possible with this design.? If they are real measurements, something is definitely very wrong.

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Please post the power numbers reported on the Diagnostic screen, so we can compare them to the ones you are computing from the Vpp measurements.

Stan

On Mon, Apr 21, 2025 at 09:59 AM, @Ludwig_DH8WN wrote:

I would use a sharp pencil type tip for the solder iron, set the temperature to 350°C, put a bit flux on D109, a bit solder at the tip and touch one side of D109. After a few seconds I would try slightly to lift this side of D109 using tweezers. After this the same for the other side until D109 is free.

Nothing beats TWO irons, one in each hand, for removing such components.? Touch each end and lift it off.?

I have been evaluating two of the Pinecil irons (with the shorter tips) and am pretty impressed.? I am able to drop the tip temperature 30-50°F and get the same results as my older Weller irons, which now are getting old and failure-prone.? Lower temperature bodes well for the longevity of the tips and helps avoid scorched flux.? The irons sleep when no motion is detected or when you long press the "-" button, another tip saver.? These behaviors are among many programmable parameters, I left most at default settings until I understand the extensive "Iron OS" documentation.

ST-D2 and ST-B4 seem to be the most useful tips thus far, on mostly smaller work.? Having the temperature sensor located right at the tip helps them punch above their weight when soldering e.g. copper alligator clips to AWG14 wire.? Quick and easy, no waiting on the iron to catch up.??

They have a power display and pop right up to 50+ watts when I contact the joint, the response is near instantaneous.? I have found that I do not need the little screw which clamps the tip, the internal spring holds well enough.

If these hold up I think I have found the solution to my aging soldering station problem.

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73, Don N2VGU

On Mon, Apr 21, 2025 at 10:59 AM, Jerry Gaffke wrote:

What you are seeing sounds like correct behavior to me for Q508 when in receive mode with RX at 3.3v.

Thanks for the correction, Jerry.? I mis-spoke regarding the voltages at Q508, and it does appear to be operating correctly.

ON a hunch, I ordered a new batch of BS170s from a different supplier.? It looks like I got a bad batch for my last replacements.? Testing a couple of the ones I hadn't used, it looks like the pinout are reversed on them, which explains why they were frying as soon as I turned on the power.? I don't know why they originally fried, but I suspect I might have accidentally shorted something because of a piece of debris on my work table.

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It looks like I am getting power out now, according to my oscilloscope when testing across the dummy load.? I got the following values:

Band (m)	Vpp (V)	Vrms (V)	P (W)	Current (mA)	Voltage (V)	SWR
160	67	23.5	11.0671	30.5	9.8	1.4
80	44	16	5.13026	30.5	10.1	1.3
60	102.5	35.9	25.8279	30.6	9.6	1.1
40	42.5	13.5	3.6523	30.5	10.1	1.15
30	90	32.4	21.0373	30.5	9.6	1.05
20	30	10.6	2.2517	30.4	10	1.12
17	44	15.7	4.93968	30.6	9.7	1.05
15	28.5	10.1	2.04429	30.3	10	1.11
12	49	17.9	6.42104	30.3	9.7	1.06
10	35	12.7	3.23226	30.4	10.1	1.09
6	50	33.7	22.7593	30.5	9.7	2.1

12m, 17m, and 80m all look good.? 6m is unreliable because it's outside the bandwidth of my oscilloscope.? 10m is questionable because it's right on the edge of my bandwidth (it has 50MHz bandwidth, and the rule of thumb is you want 2x the signal you're measuring).? I'm a little concerned that 15m, 20m, and 40m are so low, but my bigger concern is why 30m, 60m, and 160 are all so high.? Any ideas??

Debugging can indeed be discouraging, but please don't give up.? We'll continue to help.

If you limit your current to 250-300mA, it can't burn up the BS170s - it also won't give full power out, but may be a better debug setup than the diodes.

When you say the BS170s let out smoke the moment power was applied, do you mean when you pressed the power-on button, or when you tried to transmit?? (different debugging paths depending on the answer to this)

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And if you're ready to have someone else work on it, you can mail it to Jeff W1NC and he will fix it for you for the cost of postage and parts, and let you know exactly what was wrong.

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Stan KC7XE

On Mon, Apr 21, 2025 at 09:59 AM, @Ludwig_DH8WN wrote:

After a few seconds I would try slightly to lift this side of D109 using tweezers.

Jamie, hope all is well following your surgery!? In summary, I removed C17 and inserted a wire into the now empty PCB hole connected to R6.? That wire runs to the ring terminal of an 1/8" TRS jack on the back panel of the enclosure.? The TRS jack sleeve terminal is grounded to the power supply barrel connector.? I set the QMX band configuration to use +5V PTT on transmit and ground on receive for the 30M, 20M and 17M.

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This system works reliably and as Allison stated, only draws 3mA from the QMX PTT-P circuit.

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73,
Jim - AE5JE

Jerry,

Thanks.? I'll give it a try as soon as I can (probably over the weekend).

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73,

Mike, KL7MJ

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I put you on the list...

Note that if we do a group buy again, we will either do V2 or V1.2, but not both.

Still evaluating V2 design performance...

Stan KC7XE

On Sun, Apr 20, 2025 at 04:52 PM, Randy Paulson wrote:

Source on Q111 = 10.6vdc. With a scope I see a PWM'd square-ish wave from +11.9 to +10. Not returning to 0. My suspicion is that this is due the Q111 drain floating.?

No.? L102 and C106 filter the voltage, trying to average it, so it won't go down to zero.

But this is BAD, and needs investigation before replacing D109.

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The processor produces PWM (the PWM_3V3 signal) trying to get the 'averaged' voltage at the source of Q111 to 3.3V

- NOT 10.6V.

The processor measures this voltage, actually half this voltage, at the ADC_3V3 connection.?

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Since you see 10.6V ave, the processor's measurement of the ADC_3V3 voltage is likely not working.?? If the processor can't see the voltage on ADC_3V3, it will continue to increase the PWM percentage to try and get it there, giving a too-high voltage.? This causes D109 (when present) to conduct and keep the voltage near 3.3V, and possibly burning it out.? So check carefully to make sure R110 and R112 are in place, and measure the voltage at the ADC_3V3 junction, which should show VDD/2.? Also inspect to and make sure the processor pin where ADC_3V3 is received isn't shorted to something (solder flake, etc.).

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If the above failure is happening, and you bring up the diagnostics page in the terminal program, you would likely see the 3V in 'linear' mode, and the 3V 'duty cycle' equal to 'duty max', which means the processor is trying hard to get the 3.3V smps working but not seeing the result.

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[Alternately, something in the PWM circuit may be broken (e.g. Q109, Q107, Q113), but if that was so, I don't think you would see the pulsing at the source of Q111.]

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Good luck, Stan KC7XE

Hi Joel.

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I'm wiring up my Pacific Antenna mic now.? The manual says that the bare wire is ground, but there is no bare wire :-)

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Mr. Ohm Meter says:

RED = TIP and I understand that TIP is PTT.

WHITE = RING and I understand that RING is MIC

YELLOW = SLEEVE, which of course is GROUND.

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Does that sound about right?

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Best,

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Jim

K8DDV

Real Dummy Loads are easy to make. ?Twenty 1k quarter watt resistors in parallel make 50 Ohms and will safely dissipate five watts if they all have good air separation.

On Mon, Apr 21, 2025 at 06:59 AM, @Ludwig_DH8WN wrote:

I would use a sharp pencil type tip for the solder iron, set the temperature to 350°C, put a bit flux on D109, a bit solder at the tip and touch one side of D109. After a few seconds I would try slightly to lift this side of D109 using tweezers. After this the same for the other side until D109 is free.

I have successfully removed D109 on QMX+ using this technique.? I first used some 60/40 solder on both ends of the diode, with a hot iron, to melt the lead-free surface-mount solder, and mix it with the lower-temp solder (kind of like what happens with chip-quick).? Then heating 1 end at a time I was able to remove the diode.

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Then yes, it needs replaced with only a similar 3.6V 500mA diode; not too hard to put in place with tweezers, and solder one end at a time with a narrow tip and tweezers to hold it in place.? If you need one I can send one to you for a couple of $ so you don't need to pay a huge shipping fee.

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Stan KC7XE

On Mon, Apr 21, 2025 at 11:15 AM, NQ5P wrote:

I am using an external mic and the beta version -003 for SSB. Even the slightest tap or shuffle on the desk with my QMX+ causes the VOX to trip. I am confident the external mic is not causing the VOX to trip. Would Hans spur removal still work if I removed the QMX+ internal mic and would that get rid of the unwanted VOX trips? Or do you think Hans could isolate the internal mic from the VOX detection in firmware?

I noticed the same issue, but raising the VOX Threshold to about 35 or higher completely resolved the issue, and it was still plenty sensitive for my voice (though this probably depends on the microphone being used).? I'm pretty sure it was the internal mic triggering the vox - pressing an encoder button would always trigger it.

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If you want to remove the internal mic, everything should work fine - Hans didn't need the internal mic signal for the noise removal, he just needed an A/D converter in the same group.

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Stan KC7XE

Maybe you could buy a pack of 10 units from QRP-Labs shop, you would be sure to get the good devices.

73 - Pierre - FK8IH

It's actually L515 and L516 (20/17/15) that have a number of turns lower than their 'design' inductance.

L517 and L518 are right on target.

You can see this by using toroid.info to calculate the number of turns for a given inductance and toroid type.

I suspect that the reason L515 and L516 have a low number of turns, is that during testing Hans found that the lower numbers worked better than the original design simulation.? He does clearly state in the assembly guide to not try to measure/match the inductances, but to use the number of turns given, then change from there as needed.

On Mon, Apr 21, 2025 at 01:23 PM, @Ludwig_DH8WN wrote:

never saw a broken IC403

I had to replace a failed IC403, so that is a possibility.? In my case it was caused by a probe-slip while I was measuring something, which caused an over-voltage on Vcc.??? Kai, if you think IC403 may be the problem, and have capability to replace SMD parts, I can mail you one (if you are in the USA, international postage may cost more than it's worth) - I ordered 10 when I replaced mine, and have extras.

Stan KC7XE

Glad to find some traffic on this topic. I am surprised these coils have similar number of turns to the 20/17/15 meter LPF.?

and likely wrong inductance.?

but a few thousand rigs before me, I will comply. Maybe I may tack solder these.?

curt

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The SMA terminator which comes with the NanoVNA can only withstand 1W, maybe 2W Max.?