I have a Audison amp that I just picked up and it turns on, the green power light comes on with no other lights. There is no sound coming from any of the channels. Any one can lend me a hand on where to start? It looks like the bottom of the amp got wet, there is some corrosion on the aluminum end caps. Here are some pictures of the board.
Attachments
I have no information on this amp so I'll suggest starting with the simplest thing. Connect speakers and a signal source and operate all pots and switches through their entire range to see if any channels pass any audio, even intermittently.
Clean up everything with isopropyl alcohol. Clean up the pots and switches. Check that RCA's jacks are not being broken and they have good contact. You can trace at least if signal is coming into the PRE-AMP.
I cleaned everything with some alcohol and operated all the pots and switches. No audio came from any of the outputs.
I don't want to start an argument but alcohol isn't a good contact cleaner. You need something that will stay on the contacts, will lubricate and will carry away any contaminants.
That said, the problem is now likely in the muting circuit. I'm assuming that you've already confirmed that the amp is producing both positive and negative rail and regulated voltage.
That said, the problem is now likely in the muting circuit. I'm assuming that you've already confirmed that the amp is producing both positive and negative rail and regulated voltage.
I'm only using isopropyl alcohol for the board to clean it up.
For switches, relays and potentiometers i use Contact Cleaner.
For switches, relays and potentiometers i use Contact Cleaner.
I'd suggest using acetone on all but soft plastics, which will be damaged by the much stronger acetone. Virtually nothing inside an amp is damaged by acetone. It's much quicker to evaporate and contains no water (compared the 70 or 91% alcohol that most people use).
Perry,
I have voltage coming in and the power LED is lit. Are you referring the the rail voltage for the FET'S? Where is the muting circuit and how would I test that?
I don't have any information on this specific amp. I was hoping that someone who does have this information would give you specifics but no one has yet.
The rail voltage is the positive and negative on the output transistors.
The regulated voltage is the positive and negative voltage on the power supply pins of the op-amps in the preamp section.
The op-amps in the output section (near the bias pots) are likely used with switched voltage to serve as the muting circuit.
Measure the DC voltage across pins 4 and 8 of the 8-pin op-amps.
The rail voltage is the positive and negative on the output transistors.
The regulated voltage is the positive and negative voltage on the power supply pins of the op-amps in the preamp section.
The op-amps in the output section (near the bias pots) are likely used with switched voltage to serve as the muting circuit.
Measure the DC voltage across pins 4 and 8 of the 8-pin op-amps.
I don't know how the LM324 is being used. It's not generally used for audio.
What do you mean by in and out? Each op-amp channel has 2 inputs and one output, 4 each for the LM324.
What do you mean by in and out? Each op-amp channel has 2 inputs and one output, 4 each for the LM324.
Pin 4 would be the input no? I only have 60mV on pin 4 and 8 should it be the same as the voltage coming into the amp?
Where you referring to different op-amps?
Where you referring to different op-amps?
The LM324 isn't an 8-pin op-amp.
Pins 4 and 11 of a 14 pin op-amp and pins 4 and 8 of an 8-pin dual op-amp are the power supply terminals. Look up the datasheets to get more familiar with them.
Pin 11 may have no voltage as it's possibly connected to ground. Pin 4 would likely have 12v if it's being used as part of the primary control circuit.
Pins 4 and 11 of a 14 pin op-amp and pins 4 and 8 of an 8-pin dual op-amp are the power supply terminals. Look up the datasheets to get more familiar with them.
Pin 11 may have no voltage as it's possibly connected to ground. Pin 4 would likely have 12v if it's being used as part of the primary control circuit.
Ok sorry iam trying to learn the components.
Are the 2 LM833'S the op-amps you where referring to test?
Are the 2 LM833'S the op-amps you where referring to test?
Do you know what the bias pots are?
Did you read the basic repair page?
bcae1.com - Car Amplifier Repair Tutorial - The Basics
Did you read the basic repair page?
bcae1.com - Car Amplifier Repair Tutorial - The Basics
If I test any of the about mentioned pins on either on of them I just get 60mV. Dose this mean that they are being muted?
Did you read that page?
I am confused. Why did you look at the LM324s when the 8-pin op-amps near the bias pots were given as the op-amps to check?
I am confused. Why did you look at the LM324s when the 8-pin op-amps near the bias pots were given as the op-amps to check?