Re: kit-projects AGC with uBITX v5 - need help #v5


Rob French (KC4UPR)
 

Black to ground, resistance, below.  To be clear, this is measuring from the square pad at the end of the diode, where I have the thin black wire soldered in the picture.

OFF (down) - 0 ohms
SLOW (middle) - ~800 ohms
FAST (up) - ~800 ohms

So clearly something is not right here.  I'm guessing that SLOW should resolve to 1M and FAST should be something less (470k?), but not 800 ohms! 

I also went and individually measured the two resistors.

The 470k resistor... I am able to measure a good value across that in OFF and SLOW. When I measure it in FAST, it shows as a short.  I don't think that makes sense.

The 1M resistor... All switches positions, it measures as 0 ohms.

Unless there is other broken component providing a path to ground, my guess is that something is broken in my switch. I do know that I had removed a washer or nut from the base of the switch in order to have it mount flat against the inside of my rig.  I wonder if I overtightened the mounting nut and caused some type of mechanical failure or deformation inside the switch.

I'll need to verify, but it should be an easy matter to desolder those connections and put some jumpers in to test the settings. 

What's the part # on that switch?  I'll probably need to order a couple.  Or, alternatively I could make up some little relay circuit board to put the AGC under software control...

Regards,
-Rob KC4UPR

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