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I don't think LIN_REG_EN is turning "off" at 80ms--I think what we're seeing is the handoff from the initial supply voltage (through PWR_ON?) to the 3.3v signal from the processor PD7 once it has

Was successful today with WS (See picture) but not without hassle I believe caused by Windows OS and not the radio. About the time I think I have the turn on/connect/ enter sequence down pat something

I used the ?QMX yesterday in what I call hybrid mode QMX TX, Web sdr for Rx works a treat if remaining on one frequency. ?Checked everything as far as I could but can't find any errors, even removed

No, it did not appear to do so. ?If you look at my original scope traces you can see that VCC starts right around 1V because I had been turning the QMX on and off as I adjusted the scope trying to

Found the part ok. $0.23 and shipping $7. <sigh> Have to try to guess what other parts I many need to justify the shipping. 73, Cliff, AE5ZA

According to the assembly manual it says "Finally, there should be NO connection between A and B. Hold one probe on any A point and the other probe on a B point. That should read infinite resistance

Well, Steven I owe you on this one. You called it right to the component. The short was on the 5V rail and the component was D108. That is sure a tiny little diode. Going to be fun to put a new one

It's possible I measured the wrong thing? ?I measured it from what I thought was pin 3 of the 3v3 SMPS board. ?The middle pin on the top. Jonathan KN6LFB

Hi Wayne, To answer question 3… there is a better transistor for replacing the BS170’s - TN0606. The data sheet can be found

It looks like about 38 seconds or so, if I'm measuring this right. Jonathan KN6LFB

Here's a tighter view: And zoomed in on the linear regulator portion. ?Vertical scale in both is 500mV/division with a -1.5V offset. Here's a similar trace with channel two showing LIN_REG_EN.

I don't see why it should not work with the AOD21357. Specs are very similar to the AOD403 and both are well over dimensioned for this purpose. I would try it if I were in your shoes. Experience is

IF IT FITS and you want to use a premium cap, I would use the Kyocera TPSE477K010R0050 for $2.58 at Digikey, qty 1. It is 470uF 10% tolerance 50 milliohm ESR, Not cheap, but this series is surge

Or put an absorptive bridge between the QxX and switch it in for tuning, then out to operate. Also don't let the tuner auto tune when it detects a change in SWR. -- 73, Dan? NM3A

The 1N4148 diode in series with the linear 3.3V output is a necessary evil to prevent backward current flow once the 3.3V SMPS rail comes up. However, it destabilizes the linear 3.3V rail as noted by

-- 73 Karl KI4ZUQ

Looks good Karl, does it work good for you? I have one sitting in a box in Florida waiting for my return to assemble it. 4S has some good kits and they have a great organization too. I activated my

Jonathan, After turning the power OFF and having the 3.3V VDD drop to 0V, how long does the 5V VCC stay at xxV ? 73 Kees K5BCQ

Hello Hans and Jonathan, The plots require some questions to be answered in my mind. 1) What is happening to 3.3V between t=80ms and t=200ms after Power ON ? Need more detail on the actual voltage

Just curious if anyone has seen this and might know what's going on.? Using Putty on the CAT port of a QCX-Mini, the QCX returns a (`) with each character typed.? ?For example, if I type FA; and