Re: Gate voltages to BS 170s are not stable. Need some suggestions.
#help
#problem
#qmx
Walt,
As the operating manual has not been released yet maybe the best description of the start up sequence is what Hans wrote here:
JZ
John,
Is there a writeup on the power-up sequence for either the QMX or earlier rigs?? I believe I've seen something like this at some point.
Walt
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Re: #QMX is birthday cake proof! (Was: #QMX is waterproof!)
#qmx
It’s Hans’ birthday but I got a present. A fully working QMX in a 3D printed case.? Happy birthday Hans and thanks.? Jay? KE7OT?
On Friday, July 28, 2023, 7:16 AM, Randy, N4TVC <nn4tvc@...> wrote: Happy birthday, Hans, and many happy returns.
73, N4TVC
--
Jginaz
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Re: Gate voltages to BS 170s are not stable. Need some suggestions.
#help
#problem
#qmx
John,
Is there a writeup on the power-up sequence for either the QMX or earlier rigs?? I believe I've seen something like this at some point.
Walt
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Re: QDX V2 Configuration menu on Mac Terminal
On Wed, Jan 19, 2022 at 12:15 AM, Niels wrote:
I've just finished the build of my V1 and ran into the same problem on a Mac using screen. The solution is to first press Control-A, followed by Q. The way screen works is that Control-A tells screen to send the following letter as a direct command.
Ah, that's brilliant, thank you! I was stuck on how to back out of the terminal mode apps. For the record, for other Mac users wondering exactly how to connect via the Terminal to the QDX, here's the command I'm using:
screen /dev/tty.usbmodem544201
However, you can't just copypaste that, because the exact device name (the "/dev/..." part of that command) changes on different machines, and even depending on which USB port you plug it into.
You can find the name by deduction, by comparing the contents of?/dev?with and without QDX attached. Run this command twice, once before and once after plugging in the QDX:
ls /dev/tty.usb*
And look for the new device that appears.
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QCX+ display has a text box missing the left column of dots
I have finished a 20 and a 40 QCX+ and am in the setup stage process with both. I have issues with the setup but that is for another thread. One of the front panels when I fired it the 7th column of text blocks is missing the left edge column of dots on both the top and bottom line. I have interchanged the two front panels with the two main PCBs and the results confirm it is the front panel as it does it on both main PCBs and the other front is fine on both. I can "read" the front panel and so far have not had an issue where the missing dot column caused problems. Is this an issue or should I just not worry about it and go about trying to get both of the setups resolved?
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Re: QDX won't load firmware...?
Hurray!
73
Paul -- AI7JR
On 7/29/23 14:03, Leigh KG7WED wrote:
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I was out of town last week, but got to take a look at the QDX
again today. I found a manufacturing defect that was the source of
the problem, and fixed it.
The fault was indeed with inductor L16, through which the VCC
supply must flow to IC10 (the PCM1804). Here's what I was
measuring:
The node labeled in red as 5V, at the bottom of C24, is where the
circuit board trace runs from the right side of L16. So on one end
of the trace, I was seeing the 5V that should be there. But at
L16's right terminal, I was only seeing 1.7V.
Gently I pressed down with the multimeter probe, applying pressure
to the top of L16's right side. The displayed voltage on the meter
started to rise, and when it hit about 3V, the QDX's front panel
LED flickered fast for 5 seconds, and it finished booting up.
So perhaps it wasn't ever properly soldered to that right side
pad, and was only soldered on the left side. If it wasn't
solder-bonded on the right, and only touching, that would explain
why it worked at first. Then presumably at some point after those
first few days, it got bumped or something, and that shifted the
unsoldered contact far enough apart to introduce more resistance
at that node.
Resoldering L16 (on both sides, to be safe) seems to have fixed
the issue.
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Re: Obsessive QMX tracking
Why not add a 'me too' message to this thread?? My QMX package arrived yesterday and I opened it up today to take a quick look.
At first glance, I don't see the final output tubes (valves for you Brits) in the box.? I'm pretty sure they should be big enough to be seen without digging into every little bag.? I assume they'll be arriving in another well-padded package shortly...
;-)
Thanks Hans, looking forward to getting into this one soon!
Brock VA7AV
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Re: Gate voltages to BS 170s are not stable. Need some suggestions.
#help
#problem
#qmx
Maybe D103 has open-circuited in the fault scenario? If 3.3V from the
linear regulator fails to come up, the processor does not start and
the PWM regulators never run.
JZ
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On Sat, Jul 29, 2023 at 5:05?PM Walt (KK4DF) <wewilsonjr@...> wrote:
John,
While holding down the left encoder for power on, I do get the +12V out of the 5v board and into the 3.3v board. I also so 0.75v from LIN_REG_EN while holding the encoder down. Q202 fires as well. I never get any other voltages out of the PS boards.
Walt
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Re: Gate voltages to BS 170s are not stable. Need some suggestions.
#help
#problem
#qmx
John,
While holding down the left encoder for power on, I do get the +12V out of the 5v board and into the 3.3v board. I also so 0.75v from LIN_REG_EN while holding the encoder down.? Q202 fires as well.? I never get any other voltages out of the PS boards.
Walt
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Re: QDX won't load firmware...?
I was out of town last week, but got to take a look at the QDX again today. I found a manufacturing defect that was the source of the problem, and fixed it.
The fault was indeed with inductor L16, through which the VCC supply must flow to IC10 (the PCM1804). Here's what I was measuring:
The node labeled in red as 5V, at the bottom of C24, is where the circuit board trace runs from the right side of L16. So on one end of the trace, I was seeing the 5V that should be there. But at L16's right terminal, I was only seeing 1.7V.
Gently I pressed down with the multimeter probe, applying pressure to the top of L16's right side. The displayed voltage on the meter started to rise, and when it hit about 3V, the QDX's front panel LED flickered fast for 5 seconds, and it finished booting up.
So perhaps it wasn't ever properly soldered to that right side pad, and was only soldered on the left side. If it wasn't solder-bonded on the right, and only touching, that would explain why it worked at first. Then presumably at some point after those first few days, it got bumped or something, and that shifted the unsoldered contact far enough apart to introduce more resistance at that node.
Resoldering L16 (on both sides, to be safe) seems to have fixed the issue.
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Just an observation for later (when you're down to the fine tuning issues):
My QMX arrived Thursday, finished building it by Friday morning and have been testing it since. Am currently exploring (and making QSOs) with 1__00_6.
I noticed one confusing thing - If you are in practice mode for CW, it also seems to disable digital transmit output, but doesn't display the "P" indicator.
I suspect the best solution might be just to always display the "P", but a good case could be made for not having a practice mode at all in digital.On the other hand, I have already found it handy to prevent accidental transmitting when testing. I don't know the best solution, but you probably want to worry about this kind of thing later, after some mulling!
Great job so far - ?My personal wish list is to fix the power supplies putting birdies in active bands, and to see the option of a slightly wider CW bandwidth to make tuning around easier - ?but I know you'll get around to everything eventually.
I love it so far!
M
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Re: Gate voltages to BS 170s are not stable. Need some suggestions.
#help
#problem
#qmx
John,
Nothing gets hot, as nothing turns on.? I checked the switch on the left encoder, and it still closes when pressed.? And as long as I hold it down, I see about 10mA current drain.? But nothing else happens when I press the button to turn it on.
On the 5v board, I see approximately 12v on VIN and PWR_ON.
Walt
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Me, too.?I should be working 20 m with QDX #2 right now. Instead, I'm sitting here fiddling with QDX #1. I released the genie of the radio from said QDX trying to figure out why it was only putting out? 1.7 W on 10 m. I saw him float away while I was trying to measure the voltage on D6. I still haven't figured out which component he escaped from. He seemed to have come from somewhere in the vicinity of L12, but that can't be it.
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Re: QMX died in first test run
Yes… don’t ask how I know. ? Mike WM4B ?
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From: QRPLabs@groups.io <QRPLabs@groups.io> On Behalf Of Chris Sent: Saturday, July 29, 2023 3:31 PM To: QRPLabs@groups.io Subject: Re: [QRPLabs] QMX died in first test run ? Useful info, thanks guys.? Would turning it on, then plugging it into the QMX help? It is always safe to add a delayed relay to activate dc power output after powering on supply.
73
Barb WB2CBA
?
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Re: Gate voltages to BS 170s are not stable. Need some suggestions.
#help
#problem
#qmx
Walt,
The datasheet for the processor says that its GPIO pins can source or sink up to 20 mA. A dead short to ground would burn 66 mW ( 20 mA x? 3.3 volts). That isn't that much and I don't think that it could fry your chip.
My guess is that a failure elsewhere has occurred. Does the processor get hot? Does anything on the 3.3 volt supply board get hot?
JZ
John,
I was poking around with one of the scope probes, thinking I had all else disconnected.? But I still had my dummy load connected with one probe still connected to it.? While poking around, I may have "earthed" one of the LPFx signals from the main processor.? If this was the cause, this one may not be recoverable.? The good news is that I've had my second QMX kit ordered for about a week now.
73,
Walt
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Re: QMX died in first test run
Useful info, thanks guys.? Would
turning it on, then plugging it into the QMX help?
Chris
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It is always safe to add a delayed relay to activate dc power
output after powering on supply.
73
Barb WB2CBA
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Re: QMX died in first test run
It is always safe to add a delayed relay to activate dc power output after powering on supply.
73
Barb WB2CBA
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Re: U3S and strange sudden changes in locator
Hi Andy, Thanks for your advise. I think it’s the best thing to do! Hans Merz / Pa3AAW
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Op 29 jul. 2023 om 18:14 heeft M0RON <eustace.andy@...> het volgende geschreven:
?Hi Hans,?
I think that I'd perform a reset and start again but make sure that you record all of your settings first.?
Andy?
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.
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Re: U3S and strange sudden changes in locator
On 29/07/2023 15:53, Hans Merz wrote: But when I use it "at home" *JO22*(hi) the same changes with the same "ghost locations" happen. I use the GPS receiver QLG2 in combination with the U3S. Has anyone experiences like this? Or hints what is happening? Hans, In the configuration of the U3S is a setting for "checksum" this prevents a corrupted NMEA sentence from changing the locator. But it can not be set if you want to send your locator mobile. 73 Alan G4ZFQ
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Re: QMX died in first test run
On 29/07/2023 13:32, Daniel Walter via groups.io wrote: Check it for transients before you start using it. It all sounds good, but if you have a few mSec at 12 V, you're going to fry it anyway. Dan Yes, a long time ago I made up a voltage/switched current limited supply from parts I had and data sheets. The only problem was the high voltage pulse at switch-on. I still use it and still remember the project it destroyed. I guess one day I will leave it connected to something.. 73 Alan G4ZFQ
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Leigh KG7WED
Tom Meyer
Paul - AI7JR
Mike Besemer - WM4B
Barb WB2CBA