Dan,
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never ever run a QMX with SMPS boards if the off line tests are not ok!!!
(on PCB#2)
12v goes 0v to 5.2v
Vdd goes 0v to 0.1v
It looks like a short at VDD (or a faulty PCB#2).
Please remove all subboards and check resistance at the mainboard VDD-GND and VCC-GND. Both should be some kOhm. If only a few Ohm one or more element(s) connected to this voltage rail is broken (or the rail is shorted by a solder whisker or so).
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If resistance is not ok, you have to search for the broken element, not so easy.
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If resistance is ok you have to repair both SMPS boards or use spare parts from QRP Labs.
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If all is ok you need for start at least 200 mA, use 250 mA limitation @ 6.5 V.
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73 Ludwig
