Well, yes, you can use a signal generator and an oscilloscope. That's generally how it's done in a more "professional" manner. The signal tester is more of a "down and dirty" kinda budget DIY thing. It's nothing more than a probe that connects to your output cable to bypass signal from various test points on your PCB directly to your amp. You plug your guitar into the input pf the pedal and strum it while you test.
http://byocelectronics.com/signaltesterinstructions.pdfHere's a link to the instructions for the kit we sell (which is out of stock), but it's pretty easy to make one from stuff you probably have laying around. Everyone probably has a flaky cable in a box in the closet somewhere. Cut the plug off the end that is flaky. Strip that end to expose the shielding and the "hot" conductor. Connect a wire to the shielding so that you can ground it to the pedal's ground. In the kit, we use an alligator clip, but there are probably many ways to skin this proverbial cat. Then connect a capacitor to the "hot" wire. It can be pretty much any cap. .1uF to 10uF is ideal, but even a tiny 100pF cap will work, it just won't pass very much low frequency. Connect one end of the cap to the hot wire. The other end of the cap is your probe. You can literally use the cap's lead as the probe. Just tape up the other end of the cap real good so that it doesn't short out when you touch it.
You mostly want to know if you're getting signal at the input of the BBD (pin 9 of the 3205) and the outputs (pins 6 and 7). You're voltages suggest the 3205 and 3102 are working, but based on experience, it's the most likely part to fail.
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keith@buildyourownclone.com