@ Jerry Gaffke,
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? Jerry, if your question was at me:? My QMX+ is Board V2 with firmware 1-00-027 when my occurrence happened less than a month ago.
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@ Mattie
?I see you checked your unit with 12.15 voltage applied.? ?Your results were no voltage at VDD and VCC when referenced with ground.? ?Please understand that these points are after transistor(s) that would kick in (switch on) after the Processer or Voltage Regulator circuit is satisfied with certain conditions.? ?Your unit is not meting those conditions.
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I suggested earlier that you check the Resistance with your ohm meter across VDD and Ground to see what the readings are.? This will let you/ us know if you have some damage part(s) on the 3.3v rail.? As I said earlier that mine had a reading around 260ish ohm (No Good) on that rail.? That told me that I needed to go down that rabbit hole looking for an issue there.? ?Mine ended up being that D109 was damaged and pulling the voltage to ground.? This didn't let the 3.3v power get to the proper voltage to power the circuits needing that power rail i.e., the brains of the unit, the processor.? ? If you choose to, please look at my earlier post and share your findings with what you get on checking the resistance across VDD and Ground. THIS IS WITH NO VOLTAGE APPLIED TO THE QMX+.? ?I just opened up my unit and confirmed that my resistance reading taking from JP105 VDD to ground is 2.54 K Ohms on the working unit.? Let us know the results.
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?If your results with the ohm reading is not above 1k ohms, I would then try testing the unit like I said in the earlier post.? ?Apply power (If you can put your unit on a regulated power supply with 7V, 250m amp limit setting).? Place a finger on the Q109 or Q111 (my version 2 QMX+ these were found on the bottom of the main board).? While holding down the Power Button, did the transistor get hot to the touch?? If the answer is yes than something is pulling too much current and not allowing the supply rail to get to 3.3 volts.? for me, the diode had shorted and cause the issue of pulling too much current to ground (D109).
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?I just trying to help so if you could post the results of your findings this could help the group understand what your next steps is/ are.
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73 KQ4DTX
