I can understand why it would take some time to find the short. As college students they had not had many opportunities to debug first silicon. When you get garbage data, there are a lot of possible causes that have to be eliminated before finding the true cause. After 30 years in the industry, still nothing beats the thrill of evaluating first silicon.
@Max: Did you have a mentor while you were working on your projects as a kid? My daughter loves to build robotic projects, and fortunately she lives in a house with mulitmeters and scopes in the basement...Although, her robotic bug still only goes in circles at the moment. But it does drive the dogs CRAZY :-)
@Janine: Max: Did you have a mentor while you were working on your projects as a kid?
When I was 11 or 12 and had just moved to the high school (in England we went from Junior school to high school -- no middle school) I had a friend called Carl Clements -- when the other kids were playing soccer during breaks, we'd be drawing circuit diagrams in the dust on the playground -- apart from that, all I had was my Practical Electronics hobbyist magazines.
>a frequency counter kit because my father wanted to know the frequency of is CB carrier. It never worked and I had no calibrated signal source to test it.
Was it a Heathkit with an adjustable timebase? An NTSC color TV receiver made a very accurate home-hobbyist calibration reference. If one measured the chroma oscillator it was locked to 3.579545 MHz from the TV station, and it was sometimes possible to pick up the strong horizontal sweep emissions of 15.73426374 KHz using a short 'antenna wire' without even opening the (non-metallic) cabinet. Before color the horizontal frequency was 15.750 KHz.
OK, maybe that's so, but when was the test equipment last calibrated? What was the uncertainty in the measurements at that time of calibration? Is there are calibration history on the test equipment to show that the equipment is most likely working? Did you look for another way to test? Did you use a check stadnard on the test equipment before using it to get some confidence or did you just pick up the equipment and assume it wored within tolerance.
Remember, your project is more likely than not the problem. If you verify the test equipment boefore using it, then you eliminate it as the culprit.