wrote in message
ups.com...
i baught an old APPLE - MAC PLUS computer . i pluged it to 230 v ac .
nothing happened .
so i opened the cover . i saw the fuse inside it had burst . so i
changed a onw 5 amp fuse . and i powdered it ON . i saw spark of fire
in POWDER/SWEEP board . and again the new fuse had burst . i think
some component had burst too. so please give me an idea to repaire
it . OR give me the circuit ,so that i can verify it...


Isn't 5A a bit large for the fuse? You may have caused further damage by
installing too large a fuse.

These are not difficult machines to work on, just use standard switchmode
power supply troubleshooting procedures to track down defective components.
You likely have a shorted rectifier or chopper transistor on the input side
of the power supply. They're notorious for cooking flyback transformers as
well.