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Finished building QMX+.? All seems well except that when pressing the encoder to shut down. I get the Shut Down Msg, it goes away, but the LCD still stays lit. Once that happens the encoder no longer functions.? If I remove the dc power and plug it back in all is well until I try to shut down again.

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I am receiving and sending ft8 with no issues. According to Putty screen anywhere between 3.2 and 4.2 watts on all bands.? PSK Reporter shows being heard all over the US and Europe.

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I have researched the Groups post, but no real solutions.? I have inspected solder joints, removed and inspected both sides of the 5V and 3 volt SMPS.? I do not have an oscilloscope but do have DVM.

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Any thoughts?

Thanks,

Scott - K1SMK

Liverpool, NY? USA

I've a similar thing with a QMX.? What sort of power is it drawing in the post off state?

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HI Chris, Thanks for responding.

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Not sure I measured this correctly.? As an FYI, I built the QMX+ for 9V.? Using a buck converter to drop my 13.8 PS to 9V.? With just the buck converter I measure a draw of 4.3 mA.? QMX+ when turned on measured 128.8 mA.? When I shut it off, again the Shutdown Msg disappears, but the backlight stays on, the measurement is 92.6mA.? Whether I measured correctly or not, that tells me that it is not going into a completely off state.? From what I read the logic is not getting the message to shut down.? After that, I have no idea where to go.? Again reading, might there be an issue with the 5V smps?? I have double checked and it does not appear to have the known short.? ( If it did, I probably would have already smoked the unit!!)

Thanks,

Scott

Let's look at what's happening:

When you do the 'long-press' to turn off the QMX+, it indeed shuts down, as reported on the screen.

At the end of the shutdown process, the QMX+ firmware turns off (sets to 0) the PWR_HOLD line, which turns off the 12V power rail.? This in turn causes the 5.5V and 3.3V supplies to turn off, and the processor turns off since it no longer has voltage.

In your QMX+, for some reason this is not happening.?

Since the power never went away, the processor never resets and the firmware doesn't start up again, so you have to remove power to cause it to execute the startup sequence.

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So the first place to look is at the connection of the PWR_HOLD line between the processor and the SMPS.? Since you have a rev1 board, this goes through the angled connectors between the 5V smps card and the main QMX+ board, pin 7 of JP101/102.? I would first use a DMM to check for continuity between that pin on the top of the SMPS to its counterpart on the bottom of main board (it may be too hard to probe the processor pin directly).? Touch up all those solder joints, and see if the problem goes away.

Thank you very much for your clear explanation. Based on a few other posts, this is what I thought might be happening, but didn’t know what to check. Will give it a whirl tomorrow and report back. Many thanks,

Scott

Hi Stan,

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MANY MANY THANKS.? Even though pin 7 visually had a good looking solder joint, when I tested continuity it was giving me some resistance instead of full continuity.? A touch up with the soldering iron and full continuity.? Plugged the QMX+ in, startup normal.? Upon shut down, Shut Down Msg appeared, then disappeared and YIPPEE, the LCD screen shut off, and pressing the on/off button the QMX+ started right up again.

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Again, thanks for your clear directions and interpretation of a where the issue might be, and the fix.

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Scott,

K1SMK