| nxs1qaz2wsx |
I'm wanting to build an amp or something.
I have a Boss 1400W that fried the power circuit. It did work on one channel but has since stopped. Can I just run two 12V batts making 24V and hook onto the circuit board after the quad diode phase of the trans out circuit?
-Thanks |
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| sdoom |
Hi
is it only the power-supply section that is fried or is it also the amplifier-section ?
Usually I start resoldering every single solder joint . Thatīs eather due to the age of the amplifier or because it is made in korea/china. they really lack solder quality.
After that I can make sure there are no bad solder joints anymore.
Then I start testing the output transistors in the amplifier section with a diode tester (digi-multimeter usually have this function) , you can also use an ohm-meter to check for shortended power transistors.
If they are ok I take out the Mosfets in the power supply section and test them with a small test curcuit as you cannot proof that they are ok by using an ohm-meter. One major problem here is that in almost all amplifiers they parallel mosfets, therefore I always take them out and test them piece by piece.
If you like to , I can email you the test curcuit, itīs small and simple.
But to answer your question: no, you cannot just hook up 2x12V to a car amplifier. You need at least 2x20V , because in 99% of all car amplifiers they generate voltages around 2x25v up to 2x80V ... and again from that voltages they generate 2x15V with Z-diodes or voltage-regulator IC (eg. ĩA7815/7915) . Besides that, you also need to bypass the remote-turn-on curcuit: on some amplifers the remote turn on activates the inputs of the power-amplifiers . |
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| nxs1qaz2wsx |
| first the power supply transistors fried on one side, but it still worked. Next it stopped all together and i hear a clicking around the ic chip when power is connected and disconnected.....oh well. |
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| sdoom |
well, if the power-supply mosfets are fried and have a short the transformer makes a "klicking" sound once power is connected and disconnected.
you see that each power - transistor is connected to a resistor ( usually between 27 and 100 ohms) , connected to the transformer coil and the third leg is connected to ground. You first need to take all the power transistors out. then connect a scope to one of the resistors . You have to see a nice clean squarewave signal. repeat the testing with each of the resistors . if you get nice squares than you can replace all of the transistors and the power supply should be fine.
I assume that eather the rectifier-diodes are also fried or some of the power-transistors in the music-section are fried. you will first have to check all of the power devices if they have a short before you reinstall the new power-supply transistors.
Sorry about my English, it used to be a lot better 10 years ago when I was living in USA.
Stephan |
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| sss |
| quote: | Originally posted by nxs1qaz2wsx
first the power supply transistors fried on one side, but it still worked. Next it stopped all together and i hear a clicking around the ic chip when power is connected and disconnected.....oh well. |
fried transistors are like a short circuit !
it was a high power amp (1400w right?) so i think its worth to fix it, to do that u should separate the power supply from the amp circuit somehow , then fix the power supply ,first try changing the output (fried) transistors see if it helps .fixing the amps is easy ;) |
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