diydidi
Active member
I have a Large power amplifier that needs repairing for a client of mine.
It's a no-name brand stereo power amplifier and uses TO-3 lateral mosfets.
It has a large 500VA toroidal power transformer as well as a smaller 60VA toroidal transformer for the relay speaker protect circuits.
The builder didn't add any fusing except for a large 20A trip-switch wich doubles as the power-on switch too. This trip switch is to big in my opinion and might never trip during a fault..
It at least has a soft start circuit built in for the large transformer.
I would like to make it safer by adding a fuse on the mains side.
My question is does each transformer need its own primary fuse?
Also how does one go about sizing the fuses? I assume they will all be slow blo.
Mains where I am is 230V.
It's a no-name brand stereo power amplifier and uses TO-3 lateral mosfets.
It has a large 500VA toroidal power transformer as well as a smaller 60VA toroidal transformer for the relay speaker protect circuits.
The builder didn't add any fusing except for a large 20A trip-switch wich doubles as the power-on switch too. This trip switch is to big in my opinion and might never trip during a fault..
It at least has a soft start circuit built in for the large transformer.
I would like to make it safer by adding a fuse on the mains side.
My question is does each transformer need its own primary fuse?
Also how does one go about sizing the fuses? I assume they will all be slow blo.
Mains where I am is 230V.
