I bought the project lab 300 about 23 years ago, and finally decided to work on it. LOL.
I still have all the parts and when I did experiment # 1 (makes the speaker sound like a bird), I thought I smelled something burning. Experiment worked correctly and I thought I was just imagining it.
Then a week later I did project # 2. Its a simple AM transistor radio. I put it together, had the ear piece in my ear, turned it on, turned the control knob to tune it, and smoke came out from under the unit. This experiment uses 6 volts of power.
It was a bit funny in some ways but kind of serious in other ways. I thought these kits was 100% safe no matter what I did? I am using Eneloop batteries which I'm sure wasn't available when the kit was bought. But they are 1.3 volts each instead of 1.5 volts. So I would think that would ok. I measured the different voltages coming out with my multimeter and all seems ok.
Enclosed is the different pictures of the lab. You will notice a melted area where the switch is at. That's where the smoke was coming from. As you can see, nothing inside the unit looks corroded or melted, etc.
So questions are:
1. What did I do wrong?
2. If I wanted to do the experiments with a breadboard and such, how would I replace the transformer, terminals, antenna, etc the lab has?
I did order another lab off e-bay, but don't plan to try again till I get some feedback. Also, feel free to ask any questions. I do appreciate any help I can get with this. I know its been a long time coming, but I would like to work thru all 300 experiments, but want to do so safely.