NVA AP50 Stereo Amplifier Repair - Pt. 1

[@mikecass8306]

Wow what a mess, but sounds OK 😁😁😁

[@edwardmenzies6736]

Another great amplifier video. When you tested the output transistors with your multimeter in diode mode and they were in circuit, do you ever have to be careful about the readings with it being in circuit ? I know you measured a short between the collector and emitter in circuit but do you have to be careful as there could be a resistor or another part in parallel that could give a false idea ? I know you then desoldered one leg and tested but just curious on in circuit testing of transistors

[@AstrosElectronicsLab]

Yes, other components in the circuit can skew the readings giving you false positives. The better way to test them is using an in-circuit tester (it is basically an oscillator and is not apply a forward DC voltage), or to de-solder them and test them out of circuit. The latter, I know is a complete pain. I've done some further testing to the faulty module today and the issue is far from simply one shorted output transistor... haven't got to the bottom of it yet.

[@tamtgirl]

wow for a "commercial" product that sure is crap! i home built a duel monoblock stereo out of Chinese modules (improved with name brand transistors and caps) thats twice the quality of that thing.