/diy/ - Do It Yourself

>>906859
Also not OP, but audio gear is some of the simplest electronics out there to fix. It is an input, and an output. It is literally a matter of injecting a signal into the amp via an input, and probing around to see where the signal fails. It is literally a chain, and you are working out at which link the signal drops. Knowing the order in which to test helps as well.

A typical example (for me at least)

> Powers on? Yes? next step. No? check fuses, power switch, power supply.
> Are all inputs (CD/AUX/TAPE) affected or just one (CD)? Just one? Problem is going to be in the switching matrix, the switch itself, or the preamp for that given channel. Have at it. All inputs are out? Something in the power amp stage.
> Power up, connect speakers, sweep volume from 0 to 10 and back a few times. Hear crackling or hiss as you hear 10? Neat, your main amp stage is likely good, time to check the preamps and EQ stages.
> No whoosh? Something in your main amp stage is likely broken. Again, inject a signal and probe around to find where the signal disappears.

All electronics can be broken into blocks, and all we are doing here is testing each block. I can't find one for a consumer hifi but this TV block demonstrates the same. Assume no audio but perfect picture. Work from your output backwards, testing all blocks until you hit the dead one. In this example you'd be testing all blocks between the antenna and the loudspeaker (inclusive) to see at which point the audio signal drops. There you will find your fault. You would not be checking the sync seperator or colour decoder as these are not in the audio signal chain, and are thus unlikely to be janking out your audio. Again, learn and follow the signal chain and you're not going to get lost testing unrelated circuits.