I am building an electronic "dice" that uses an ATTiny84 to sample avalanche noise from a 2N2222 in reverse-bias and generate random numbers, which are then displayed on 2 7-segment displays. When I prototyped this on a breadboard, it worked just fine, so I decided to move to "production" and put it on a PCB.
Unfortunately, the noise generator on the PCB is running into some issues: It does not seem to be outputting (the "output" is the collector of the 2N3904) a noisy signal.
Now, as I am a student with limited means, I would usually go into the university lab and use one of their marvelous oscilloscopes to troubleshoot the signals themselves; however, they have locked all the labs for renovation or something and I can't use their equipment.
Therefore, I am asking for some suggestions as to how to troubleshoot with the tools I do have: soldering/desoldering equipment and a basic digital multimeter. I have already confirmed that all of my traces are intact and going where they should, and that steady voltages are what they should be. Every other component of the circuit works like a charm, except this generator. How can I glean some more information about it with what I have, and/or is there something I am overlooking that might explain the problem?
Thank you so much for your help.