Aiwa MX-550

binbash

New Member
Good morning, first sorry with my English i don't speak English only Spanish, I'm use google translator.
I have a old Aiwa MX-550 amplifier and Aiwa TX-550 tuner for listening music in the garage. A year ago the amplifier MX-550 starts to power off alone, and after seconds back to power on. More and more often, and now it does not power on anymore, the power button is soft, does not cut the 220v line, it goes to the main board, I have no idea where to start working and I miss the clear sound of this old man, can you help me?



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Sorry, I could not explain it correctly, it's not problem with 220v line, transformer or switch, it's a problema in the main board
 
I believe your power transistors are going bad. I cant find a schematic but show us a pic with more details of those transistors mounted on the heat sink and maybe someone can help.
Thanks.
Srinath.
 
Can you get those out and test them.
Better yet, remove complimentary pairs 1 set at a time and removing the bad pair will let it fire up and work without that channel functioning.
That channel needs the power transistors, emitter resistors and a few other parts - maybe driver transistors and that biasing one if it has one.
Thanks.
Srinath.
 
. A year ago the amplifier MX-550 starts to power off alone, and after seconds back to power on. More and more often, and now it does not power on anymore
Look over your solder connections within the power supply(s). Especially the pass transistors. Look for ring cracks around component leads.
 
I believe your power transistors are going bad. I cant find a schematic but show us a pic with more details of those transistors mounted on the heat sink and maybe someone can help.
Thanks.
Srinath.
Not so fast.Need to verify power supplies are working properly.
 
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