So I finally got around to build my QMX High band after looking at it on a shelf for the last year. I thought thing had gone pretty smoothly and appeared to be so with the initial power on. I built it for 12 vdc, but used a bench power supply set at 8vdc and saw about 170 milliamp draw. I did the firmware upload and then I couldn't get the display to work.? There was only 1.6 vdc on the 3rd pin of the side closest to the display. No other pins had voltage.? I turned up the voltage on the power supply to 11vdc, but did not see an increase in amperage, in fact? it went down to about 70 milliamps. I was even able to use the jumper to re-initialize it and saw the same readings.
So I started taking voltage readings around the board. The 2x4 (S302) and saw this
Top row (closest to LCD)
Pins
1 - 0vdc
2- 10.8vdc
3- 3.2vdc
4- 3.2vdc
Bottom row
1-2.9vdc
2- 3.28vdc
3- 3.25vdc
4- 3.25vdc
?
Then I started to poke around some more on the power supply boards, and I believe I must have been a little sloppy taking some voltage readings,? because now it won't power on at all. I can see the amperage increase to 10 milliamps when I try to turn it on, but it immediately goes back to zero when I release the encoder. Which makes me think I damaged something in the power hold circuitry, so I suppose I'm buying replacement power supplies, but I'm hesitant because that won't fix the original problem it just gets me back to where I started.
Any thoughts or ideas would be appreciated.?
