How do you find a short circuit on a amplifier?

Question

How do you find a short circuit on a amplifier?

Answer 1

What makes you think it's a short circuit and not a blown component?

There are so many potential causes of a short circuit in an amplifier that answering your question fully would take hundreds of pages.

Apart from the purely mechanical issues, for example, loose wires, dry solder joints, foreign object shorting a component or board etc to earth there's failed devices, be it a capacitor, transistor, resistor, rectifiers, diodes etc to deal with.  

The standard repair proceedure is to visually inspect the amplifer for obvious failures, such as blown or leaky caps, transistors with burn marks, black and crispy resistors etc.  Then plug the unit in the mains and check there's voltage at the output of the transformer and rectifier stages, if there is, check the voltage output at the end of the smoothing caps and the supply rails on the amp board.

Next, hook up a sine wave signal source of a few hundred mV and using a signal tracer or multimeter check the input stage of the amp and output stages to see if a signal is present.

After that check the preamp stage by stage and then the power amp section stage by stage.

If you can't understand the above then you should not even attempt to repair a blown amplifier as there's a better than even chance you'll either destroy more components or electrocute yourself which can be fatal if you get zapped in the wrong area of the amp.

If you aren't 100% confident of your electronics ability and have experience in fault finding then send it to a reputable company for servicing and ask for a quote.

Answer 2

You can sometimes figure out where the problem is with a signal injector or tracer.

http://www.northcountryradio.com/Article...

Answer 3

WTF is a dry solder joint?  Basically if you have to come here and ask this stupid question then you shouldn't be messing with it.  A signal injector and tracer won't work either if it is shorted.  what a bunch of jack a$$es.

Answer 4

First,

Disconnect your speakers to verify the problem is not from blown speakers.

Second,

If it is not blown speakers take it in and have it fixed. It may be a bad transistor, capacitor, resistor. Could also be a bad amplifier IC. Without the proper test equipment it will be very hard to pin point. People can give you all kinds of suggestions. The best thing to do if you are not n electronics repair tech is to take it in and have it fixed if you can justify the repair expense.

I had a receiver that kept blowing out fuses inside. I took it in. It turned out to be bad ICs.

I had one guy look at it one time before I took it in and he claimed he was an electronics technician. He said it was a bad transformer. He was wrong.

The repair was about $75. That included the initial inspection fee of $20.