I dragged out my old AM radio that I built (many years ago) in High School and I am trying to get in working again.
My problem is that the only test equipment I currently have is a digital multimeter. If I had a scope or even and RF generator, I think I might stand a fighting chance after all these years of not touching electronics but I am at a loss.
Hopefully someone can help me.
I am including a schematic with actual voltages I measured.
Here is some background.
TR3 was just replaced. I had to replace it with a 2n410 of different packaging. This transistor has a red mark. I assumed that was the emitter. Is this assumption correct?
TR5 and TR6 were just replaced.
I am getting hum out of the speakers. Hum changes and speaker crackles when I measure voltages on TR4.
If you look at the voltages, they seem to be off a bit but the most significant one is the emitter of TR4, Is it possible that TR4 is bad too?
Any tips on what else I should check?
My problem is that the only test equipment I currently have is a digital multimeter. If I had a scope or even and RF generator, I think I might stand a fighting chance after all these years of not touching electronics but I am at a loss.
Hopefully someone can help me.
I am including a schematic with actual voltages I measured.
Here is some background.
TR3 was just replaced. I had to replace it with a 2n410 of different packaging. This transistor has a red mark. I assumed that was the emitter. Is this assumption correct?
TR5 and TR6 were just replaced.
I am getting hum out of the speakers. Hum changes and speaker crackles when I measure voltages on TR4.
If you look at the voltages, they seem to be off a bit but the most significant one is the emitter of TR4, Is it possible that TR4 is bad too?
Any tips on what else I should check?
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