开云体育

1. On my very first startup trying to power on, I got nothing at all. I did the logical thing and reheated a bunch of connections - especially the two push button connection on the encoders.
2. After putting everything back together I tried again and sure enough the "flash drive" showed up on my computer.
3. I got the latest firmware, unzipped it and then put it into the flash drive. That's when trouble started. I guess everything takes off once it has firmware.
4. I noticed a tiny whiff of smoke coving from the 2x3 pin board (3.3 v?)
5. I immediately cut the power. Well actually just unplugged it. I was running a reduced voltage, like 8.5.
6. I checked everything. Both power supply boards seemed warm. I checked it all over again and plugged the power back in.
7. I pushed the power encoder and a transistor on the 2x4 pin board lit up - literally and burnt. It was near the far end of the board by the big cap.
   
8. I remeoved the power and started trying to diagnose it.
9. I don't think I checked resistance on the power rails to ground prior to this.
10. On the VCC rail I get an open. On the VDD rail with the burnt power board installed there is a dead short on VDD.
    (I am measuring resistance between the VCC or VDD rail and ground - open is infinity and dead short is 0)
11. If I unplug the 2x3 pin board there is no change in resistance - it is open with and open without the board installed.
12. If I unplug the 2x4 pin board there is an open and when I plug the board back in - it's a dead short.
13. I have an unfiished QMX (not +) and if I plug in its 2x4 pin board, it is open NOT shorted.
14. Oh, BTW, there is no short to ground on the V+ either.

If I unplug the 2x4 pin board there is an open and when I plug the board back in - it's a dead short.

On the VDD rail with the burnt power board installed there is a dead short on VDD.

I pushed the power encoder and a transistor on the 2x4 pin board lit up - literally and burnt. It was near the far end of the board by the big cap.?

Dear Dan,
I am in about the same position as you are... I did find a short under the GPS Module where the jumper for the VDD power was touching the

GPS antenna jack. I have been inspecting my board for shorts and opens but so far... Have not cleared the faults. If you can get it to load

the software .... You can use Putty to look and the hardware diagnostics. That will give you what the software sees. Mine says the 5V power supply is high and the 3.3V power supply is about 2.9V on the linear power supply. I can't seem to go any farther than that. I have changed the power supply boards twice. Not finding any bad solder joints and no other shorts. My board has an intermittent short on the VDD bus somewhere... But can't find it and all solder connections look good. Running 8Vdc on input voltage board draws about 200ma when turned on and nothing until I hold the power on button (Long press). Right now I don't know exactly what else to do. My 3.3V power board gets warm to the touch but so far no fire.
My front panel display has never lit up but I see the top row of digits are squares and nothing on the bottom row. Voltage to the readout but nothing but squares on it. Contrast doesn't seem to do anything but make them disappear. Woe is me. I may give up on this one and try again. My problem may be a board short.

Take care and have fun.
73 Dave WA5DJJ

Dear Dan,

I put a string of 8 diodes together and hooked that to my 12V power 
supply.? That took the voltage down 4.8 volt so it is around 7V for 
testing.?? I don't trust those Chinese power supplies.?? I use a 
regulated +12Vdc supply at 2 Amps.?? and that works pretty well.?? I 
bought a extra set of power supply boards and my QMX+ is now down.?? The 
second 5VDC SMS supply is getting really hot and not working.?? My short 
is intermittent and comes and goes when I bang the board on the desk.? 
But it quit that now and the board draws 340 ma when turned on.?? 
Nothing on the board get hot except the 3.3 Vdc SMS POWER SUPPLY.?? I 
can't find any bad solder joints.? I did get the processor go come up to 
hardware diagnostics.?? and go a picture of it .? But nothing happens 
now...? So, The new kit is here and I will try again.?? If I can't get 
this one to go... Then I will give up.

Good luck on yours...

73 Dave WA5DJJ