Greg, THANK YOU.? Pulling the display board lets it come up, drawing
~150mA at 6V. The terminal program is running, so it seems that at least
part of the CPU is OK.? Now to figure out what I did wrong with the
display board!
Again, thanks.
-Al WA1TYB
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On 3/22/2024 14:36, Greg McCain via groups.io wrote:
Just a quick thought.
Without the control board will the unit even power up since the rotary
push to power on won't be available?
You might try just removing the display.
If the current stays up, then the fault might be in the display board
or the 5v power board.
I've seen other posts where faults/ bridges/shorts in the power
boards' connector chains have caused odd problems. I took the advice
in the build instructions and clipped the one set of pins back about a
millimeter or so because I could definitely see I that a few were too
long and extended past the solder pads and awful close to other items.
Greg
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On Fri, Mar 22, 2024 at 2:32 PM, Al Simons
<al@...> wrote:
Just completed my Rev 3 QMX assembly. It performs the USB stick
emulation ok, to place the FW file on board. I did this both on
initial power-up and by jumpering AUX2 to GND. However, after FW
load, when I press the left knob it draws power for an instant and
then powers back down to 0.000A.? I'm using 7V, limited to 200mA.
I have inspected all my joints w/ a magnifier, all seem fine but
I'm considering buying a USB microscope.
To start troubleshooting I want to check the power boards.? For
easier access, is it safe to power up the unit without the control
board and display boards plugged in?
I've been monitoring this group since I placed my order.? I think
I remember a reference to a troubleshooting guide by Hans, and
another report of this failure mode, but I can't find either.
Pointers to either would be greatly appreciated. I'm aware of the
troubleshooting log Hans has posted about units he's fixed, but it
doesn't mention this failure.
Thanks for any advice and pointers.
73,
-Al WA1TYB
