Hi, can anyone suggest where to go next please.
Connect power, no current draw. press on button PC sees QMX current draw approx 160ma, load software and LCD lights up with splash screen (software version QMX ect) and thats all.
Turn off power unplug pc press start current draw about 160ma but nothing on display. wait try again nothing.
Connect to PC reload software and LCD lights up, but same situation as above. It also does not turn off the current draw if i hold the power off button.
I stripped and rebuild the contols board and check every conection and switch opperation.

Any advice would be appreciated? Mike

Michael,
If the buttons and the right encoder don't respond , check the ground connection to the control board, the upper left pin ( or either of the button contacts near the top edge).? Also be sure the mating ground pin on the main board is solid .? As noted in the manual, the six layer board grounds take a lot of heat for a good connection.
Good luck!
73 KG8IW?

Make sure you have the LCD contrast fully anti clockwise.?
--
Colin - K6JTH?

Colin
Thanks for your help.? when the software loads the led lights up and the splash screen is clear to read. but nothing after reboot.

Bruce
Rechecked the earths the on/off switch turns QCX on its is visible on the pc to load the software, it the lights up lcd and diplays clearly the splash screen. but nothing after power down and restart except for current draw.

This sounds like it is hanging waiting for the switching regulator to spin up. It will pause the boot sequence till the voltages are correct and the switching regulator duty cycle is in the expected range. Then the current should drop to about 80ma. Hans has written about the a couple of times. Finding his description will give some places to probe.?
--
Colin - K6JTH?

Colin i thought the same,
Hans posted (#103064)

1. Initialize the Flash memory, reset peripherals, configure the system clock, configure the I/O pins
2. Initialize the DMA (Direct Memory Access interface)?
3. Initialize the ADC (Analog to Digital Converter) of the CPU; we use 10 channels for monitoring supply voltage, 3.3V, 5V and Bias buck converter outputs, Fwd/Rev power from the SWR bridge etc; all continuously read via the ADC and stored in memory using DMA
4. SMPS (Switched Mode Power Supplies) initialization - this means the little plug-in buck converter boards.?
5. DIsplay init - which initializes the LCD module, switches on the backlight (depending on if you configured that to be on in the configuration menu), and writes the Splash screen text (QMX, firmware version, QRP Labs 2023).?
6. Blah blah loads and loads of other things - including eventually, the USB initialization...?
7. Eventually, audio system initialization (the I2S 48ksps stereo ADC chip and corresponding stereo DAC chip

I seem to be at 5
Switches on the back light and writes the splash screen
the SMPS come before this so thats what puzzels me about what direction to go next

Michael, not sure I understand - does the splash screen still show or did it only show one time?? What is the value of the current draw?? You can easily check to see if the 3 volt supply is working by using a ground on any of the connectors and probing any of the resistors on the control board.? With nothing pressed they should show ~3 volts.? This, of course, after power on button is pressed and released.

Bruce
0 amps i press on button and 160ma and PC picks up QMX,? i load software and the LCD lights up and shows clearly the splash screen.? if i do nothing it stays like that (lcd on and splash screen) so i unplug power.
now 0 amps press on button and 160ma and nothing else no lcd light or any text.? if i start again and load software again lcd and splash screen appear. But i cant get any further than this.

A week or so ago someone was trying to start a QMX using a current-limited bench power supply.? He chose his amperage limit appropriately, 250 mA if I recall correctly, but his voltage setting was 5.6 volts.?? Hans suggested upping that to 6 volts so the microprocessor could get the SMPS switch mode power supplies enabled.? I believe that fixed the immediate problem.? His build had several problems so at that time he said his board was dead.
/g/QRPLabs/message/107663

What voltage are you supplying?

Hi and thanks for help.
Because there is no short or high current drain i increased votage to 12v and 2 amps current. with no change.(also used my kx2 11.1v battery pack) i have reloaded software many times even older versions. but just stops at splash screen.
Mike

开云体育

When you connect to the pc to load the firmware ( now for the nth time) do you see two files already in the QMX ? The system should only go into firmware load mode automatically the first time, then you should have to explicitly request the update, via terminal mode, qmx menu select or by jumper wire.? Seems like the firmware is not being loaded to eeprom.?

Mike, check out this message from Hans??/g/QRPLabs/message/105756,?the firmware is not in eeprom but he does have some suggestions on where to look for this problem, maybe L402 47uH inductor

If you are really using 8, you should be using version 9,? Version 8 was quickly replaced due to issues.? ?

sorry 9 for sure.? only have a 10mhz scope but the voltages on pcm1804 when splash screen is on are ok on pin17 and 18 but nill on 15 and 16.just checking this out now