400 car amplifer needs to be repaired.

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That is correct, my son still have the subs.

Your right, like I said before, it is worth my time?

I am having fun that counts for something, there is a limit how much time I want to spend on this.

Someone some where has probably fixed one of these amps and knows exactly what the problem is. It would be nice to fine a place where someone posted a message that says, this is the problem replace the following part. Then it would be a 5 minute fix.
 
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it's refreshing to take on something new and solve the puzzle... look on the bright at the moment no money spent on it yet just time to break things in stages to work it out..
 
Tann-44 said:
Just noticed the tri-colour led on the front..doe's it light red then green or just stay red??
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I have noticed it is RED when battery is connected but I do think I ever looked at it again I figured it was a power ON light that stayed RED all the time. Maybe I should hook it up again to see if it turns GREEN?
 
most amps have a built in protection ic that does voltage checks..if all is ok the front bi-led will go from red to green or yellow...check the main large ic in the power supply stage.
 
type this in the inter net search Basic Car Audio Electronics follow the links there's plenty of info...
 
Someone some where has probably fixed one of these amps and knows exactly what the problem is. It would be nice to fine a place where someone posted a message that says, this is the problem replace the following part. Then it would be a 5 minute fix.
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Because it came with the box and is vary cheep. Most have been thrown away.
lots of people upgraded the amp on the box and tried to sell the stock one but no one whats it.
 
IT WORKS!!!

I put the amp back together, connected to a car battery, attached a speaker and input. The RED led turns GREEN and it works .

What is this thing??? Is this just a BOOM,BOOM,BOOM AMP????

I connected a turn table stereo to the Amp 2 L R inputs all the Amp speaker does is BOOM,BOOM,BOOM. I turned Boost down to about 5%, X-over up to 130Hz, Level down to about 10%, thats the only way to get real music out of the base speakers. It works but the music sounds VERY BAD.

I connected the Amp L R outputs to 2 more speakers I get GOOD stereo music from those 2 speakers. The Amp itself is not stereo all it seems to do is BOOM,BOOM,BOOM on the subwoofer speaker.
 
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What is this thing??? Is this just a BOOM,BOOM,BOOM AMP????
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Thats all it is, a mono subwoofer amp.
Did you look at the link I posted?
But you say now it works?
Was it hooked up right the last time you tested it?
 
When I tested the Amp a month ago no sound would come out of the subwoofer speakers. I had it connected just like I do now. I think taking the amp apart did something to make it work. I resoldered a lot of the circuit board just in case there was a bad solder joint or a cracked solder joint. I found one place on the circuit board that looked like when it was soldered at the factory the solder did not stick to the wire terminal there was a donut circle of flux around the wire terminal in the center of a donut hole solder joint. I had to resolder it 3 times to finally get the solder to stick to that wire terminal. That may have been the whole problem all the time.

I understand how this Amp works now, new technology that I do not know about, that did not exist 40 years ago.
 
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It sounds like dry joints/or bad connections... still it's working now that's the main thing... if need be connect it up to a hifi speaker and try it...

I was right about the bi-lead changing colour and dry soldering..it's the new lead free crap stuff it's not as good as 60/40 solder..
 
I think taking the amp apart did something to make it work.
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I would tap on the board here and there to make shure its not going to die agian before you put it all back together and put it away.
Glad its working now and you had fun doing it.
 
I hooked the amp back to the subwoofer like it came from the factory. I connected it to my stereo and put on some good music and fired it up with a car battery. It works great. All the amp does is make the subwoffer work. I had to dial in the best sound on the subwoofer to get it to sound good. All the amp and subwoofer does is add more base to the music I already have. Its not really my thing but I know the kids love it.
 
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