Soundstream SA 245 - Blow Fuse

[babygot]

I have no clue why the main fuse keep blow every time I turn it on. I hope some one can give some clues where to troubleshoot. even better, someone can tell me what to replace.....

I attach pic for a better communication.

Thanks

[sdoom]

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

[EnvisionAudio]

It's also possible that one or more outputs are blown. This will (sometimes) cause the MosFets to blow. The output devices are TIP102 and TIP107 - these are Darlington devices and must be replaced with exact part numbers.

[babygot]

I checked the mosfet and power output.

The Mosfets are blown - MTP50N05S 514
The outputs seems no good either - FEDI6BT 9448

I think I can find the mosfet replacement but the ouputs I cannot find the replacement.
Is anyone know the replacement for the outputs?

Thanks again

[sdoom]

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