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Share your useful testing apps, I'll start

Eldorado828

8-2-8 in the Lonestar state
Feb 21, 2016
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The Lonestar State
I know we all do some testing on our benches and not everybody has all the professional testing equipment. Either we're not on our well equipped bench or you need something on the fly so we at times have to improvise. With so much at our fingertips in this very technological age that wasn't at our disposal 15 to 20 years ago, I'm curious to see what some of you fellas have as quick smartphone or tablet tools. Share yours if you will. I'll start with one I've used a few times to put a test tone into a mic. 20200220_212241.jpg
 

Yeah a great subject. A quick and easy way to verify the audio amplifier circuit in a radio is to touch the center pin on the volume control, if you hear a hum or noise this verifies the audio circuit is working. Try not to touch any thing else in a tube radio as high voltages are in there. I use a screw driver that has black tape insulate the shaft exposing the tip.

Jay in the Grate Mojave Desert
 
Where I come from we call that the analog manual digital signal injector.

Poking it into the input of a radio's 455 kHz IF usually produces raucous noises. Used to have a AM radio station with a gospel format's transmitter a couple of miles away. Sure surprised a customer or two when I poked the output of the AM ceramic filter and a revival preacher came roaring out of the speaker.

Halleluia! The IF stage is working.

73
 

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