this amp i have is really making me mad again. ok here it goes. i have a car amp ( Alpine MRP-F356) that i just got to work again. i had made a previous thread about this amp and i found out that it was bad power transistors. i replaced them, checked the connections, no bad solder connections, it all is good. so i power it up and works but only for like 30 sec. and it shuts off or something no sound comes out. i check it and is is burning hot neer the coil area. i remove the remote cord for a minute and reconnect and does the same thing, works for 30 sec and shuts off. please help!!!
Find what devices are producing more heat
If the heat comes from the amplifier output devices then you may have bad driver or small signal transistors, open resistors, etc... causing cross-conduction on the output devices
If the heat comes mainly from PSU MOSFETs then you have some kind of cross-conduction or saturation failure here but you will require some SMPS knowledge and an oscilloscope to fix it. Sometimes some MOSFETs doesn't survive fuse blowing since manufacturers tend to use too big fuses trying to impress customers. When a MOSFET fails it may also blow the control circuit or the gate discharge circuit. You will get random failures if you don't fix the SMPS properly
If the heat comes from the amplifier output devices then you may have bad driver or small signal transistors, open resistors, etc... causing cross-conduction on the output devices
If the heat comes mainly from PSU MOSFETs then you have some kind of cross-conduction or saturation failure here but you will require some SMPS knowledge and an oscilloscope to fix it. Sometimes some MOSFETs doesn't survive fuse blowing since manufacturers tend to use too big fuses trying to impress customers. When a MOSFET fails it may also blow the control circuit or the gate discharge circuit. You will get random failures if you don't fix the SMPS properly
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