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Re: #QMX Are these Issues? #qmx

 

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Well, I thought I had an easy glide path. Repairing the Q103/Q104 short, I damaged (lost) R104 and D102. Turns out what I was seeing was, with no pull up, once connected to the supply the 12 volt supply drifted upwards until the unit turned itself on!

Repaired the board with discrete components and tried powering up again.

No Joy. :-( Looks like the repaired board is doing what it should, but the 3.3 volt supply (which had to be working before!) is not coming up because the linear 3.3 PS is not enabled. Gate voltage on Q102 is 8 V (what I've got my test supply set to). Gate voltage on Q101 is less than a volt. The 100k pull up resistor is in place, and the correct value.

Only thing I can see is the LIN_REG_EN output of the uP must be pulling it low (before the uP has enough voltage to run!) Checked for shorts, nada -- 80-100k.

Have I missed something? Any suggestions? Is the uP defective somehow, and how did it get that way when it was working, albeit strangely, before?

TIA for any suggestions!

A very frustrated,
Paul -- AI7JR

On 8/23/23 22:06, Paul - AI7JR via groups.io wrote:

Is there some kind of log for QMX issues? Don't want to bore anybody by reporting what's known, or my build defect!

Here's what I'm seeing (I've got Firmware version 9 loaded, 7volts, 250ma current limit):

  1. On application of power, initial current is 0, but goes to around 10ma after 10-15 seconds. Stays steady after it comes up.
  2. On initial power application, power on click is ignored, until the above 10ma step in current.
  3. At that point, power on click "delays" for ~10sec, then display comes on and 150ma current draw.
  4. Tune knob frequency only goes up?
  5. Long press power click displays Shutdown, but LCD never goes off, current (150ma) never drops.
  6. While "Shutdown" is displayed, band and mode can be changed!
  7. Going back to 3, if the power is interrupted briefly (maybe 200mS), device turns off. Pressing power-on click activates immediately!

I what I'm seeing "normal" at the moment? :-)

Haven't gotten so far as to transmit or receive, either one. (Need to read that operations manual!)

Please forgive if this is the wrong place to put this!

73, Paul -- AI7JR

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