You need to take the curcuit board out. Probably the powersupply-Mosfets are dead. This sometimes happens due to overload or sometimes it is because of static electricity.
What you will have to do is remove all the screws you can see on the curcuit board ( the ones that have glue on their heads) . then you can take the curcuit board out of the case.
the Mosfets are the 4 transistors that are on the bottom side of your picture. You see the round thing with colored copper wire turns ? This is the transformer. Just below to the transformers there are 4 power transistors, those are the Mosfets. Usually those are IRFZ44 or SSP60N06 or similiar types.
You will have to test those in a test curcuit to make sure they are ok , but probably they are burned and you will see it if you take the curcuitboard out. I also had one Soundstream where on of the rectifier diodes was shorted. The rectifier diodes are also close to the transforemer, on your picture those 4 things (they have the same case as the mosfets) are located to the upper right of the transformer.
You can check those with a diode tester or an ohm-meter.
That´s how I would start.
Gret. from germany
Stephan
What you will have to do is remove all the screws you can see on the curcuit board ( the ones that have glue on their heads) . then you can take the curcuit board out of the case.
the Mosfets are the 4 transistors that are on the bottom side of your picture. You see the round thing with colored copper wire turns ? This is the transformer. Just below to the transformers there are 4 power transistors, those are the Mosfets. Usually those are IRFZ44 or SSP60N06 or similiar types.
You will have to test those in a test curcuit to make sure they are ok , but probably they are burned and you will see it if you take the curcuitboard out. I also had one Soundstream where on of the rectifier diodes was shorted. The rectifier diodes are also close to the transforemer, on your picture those 4 things (they have the same case as the mosfets) are located to the upper right of the transformer.
You can check those with a diode tester or an ohm-meter.
That´s how I would start.
Gret. from germany
Stephan
hi.
I think the FEDxxxx are rectifier diodes (in a power transistor housing)
If you find the diodes burned, then I would highly recommend to doublecheck the output transistors of the music-amplifier section. Those should be bipolar types like TIP102/102 or similar.
If you can´t get the diodes, you can use any replacement type as long as they can handle enough current (from my datasheet it is 16A max. current) and withstand 100V ...... You should be able to find replacement types there.
Before you re-install the Mosfet´s hook up the amplifier to a power supply and check the gate-resistors with a scope. Even w/o the mosfets installed you should get nice square-wave signals when you turn the unit on. If not, there might be a broken oscillator-chip (e.g. TL494 or similar) or broken small-signal driving transistors.
Have fun
Stephan
I think the FEDxxxx are rectifier diodes (in a power transistor housing)
If you find the diodes burned, then I would highly recommend to doublecheck the output transistors of the music-amplifier section. Those should be bipolar types like TIP102/102 or similar.
If you can´t get the diodes, you can use any replacement type as long as they can handle enough current (from my datasheet it is 16A max. current) and withstand 100V ...... You should be able to find replacement types there.
Before you re-install the Mosfet´s hook up the amplifier to a power supply and check the gate-resistors with a scope. Even w/o the mosfets installed you should get nice square-wave signals when you turn the unit on. If not, there might be a broken oscillator-chip (e.g. TL494 or similar) or broken small-signal driving transistors.
Have fun
Stephan
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