Troubleshooting Transistor Circuits: Common Issues and Reliable Testing Methods

[k_squared]

I was using that diode/transistor testing thingy on my multimeter to verify two transistors I accidentally cooked in a circuit. I used some de-soldering wick. To my surprise, both still seem to work, but the circuit does not. What else might go horribly wrong when soldering? And is that a reliable way to test them?

I tested one in circuit, but it passed (I think this is okay given the wiring at present).

Thanks again!

 

[waht]

That depends. There are many characteristics of a transistor that a multimeter won't check. But it's possible that other components in the circuit are damaged and that's why it's not working.

 

[Dozent100]

While the above is true, simple transistors removed from a circuit, should test go/nogo, if you know the type and insert them correctly. The possibility that supporting components are bad while the transistors themselves are OK, would be indication of a well designed circuit. I would check each circuit back to the power source.
You don't discuss the type of circuit, which make it difficult to go further.