If you pulled the red transformer leads and the amp powers up, it pretty much means that the transformer is ok.
The usual problems are that the output chips die for any number of reasons. Try pulling off the connector that connects the output chips to the main board. If it powers up without blowing the fuse, then you've found your problem. If the chip is dead you can either replace just the chip or you can buy the entire board.
If you have a light bulb limiter, you can save your fuses until you get things sorted out.