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Soundcraftsmen ma5002a channel b dead

Last response: in Home Audio
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April 13, 2009 7:19:27 PM

I dont have the service manual for the soundcraftsmen MA5002A power amp and I dont now what types of transistors use to the power stage.
November 16, 2011 2:04:28 AM

I can help you repair this amplifier. If this amplifier has no power when the power switch is turn ON.

(1) Do you have any electronic background?

(2) Do you know how to use a multimeter?

(3) Do you know how to use a soldering iron?

June 3, 2012 2:23:59 PM

06/03/12

On one of the big black metal heat sink located at the back of the amplifier where the output transistors are mountd there should be about ten output transistors mounted on one big black metal heat sink and on that same big black metal heat sink there are two special transistors call Darlington Transistors. If you know how to test these output transistors you can locate which ones are NPN and which ones PNP transistors and also which TWO TRANSISTORS ON THAT SAME BIG BLACK METAL METAL SINK ARE DARLINGTON TRANSISTORS. These TWO DARLINGTON TRANSISTORS ON THAT SAME BIG BLACK METAL HEAT WILL INDICATE A DIFFERENT READING ON A MULTIMETER (VERY IMPORTANT). The Two Darlington Transistors on that same big black metal heat sink will be in good conditions most of the times. These two Darlington Tansistors on the same big black metal heat sink are very difficult to get damage. If you were to remove any of the output transistor or if you were to remove any of the Darlington Transistors Make sure that you mark the exact place and position where these transistors came out from ( very important). There should be about five NPN transistors part number 2SD424 on that same big black metal heat sink and also there should be five PNP transistors part number 2SB554. You can purchase these transistors from ebay. If you know how to test a transistor. I can help you repair this Souncraftsmen Power Amplifier. My email address is totalk590@aol.com
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