B&K 200.5 S2 Power Amp problem - Please help

can you elaborate on your statement - "all 5 channels, has had low output"? do they all have low output at the same time? Is it intermittent? Have they ever produced strong output?

There are a couple of things that could be simple to fix. 1) are the volume pots on the back of the amp turned all the way up? (forgive me for this one - it's just worth asking cause it's the first thing I would check if I had a problem. 2) Fuses blown - B&K uses internal Rail fuses. Their not hard to replace but you have to open the amp up and be comfortable working inside. Also you need to know how exercise safety around high voltage circuits.

I found a document I previously received from B&K showing the fuses used on each of their amps. Below are the spec's for the Ref 200.5:

Reference 200.5
Main(Line) - 15A SB/250V
Rail (internal) - 6A SB/250V
Speaker - 6A SB/250V

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since you have power you definitely don't need to worry about the main fuse (15 amp), and likewise you have some sound so you don't have to worry about the speaker fuse) The Rail fuse is a 6 amp Slow Blow with 250 volt rating (6A SB/250V)

Here's the fuse you want - they have them at radio shack:
6 amp Slow Blow fuse

How does your amp sound other than it's not loud? If the rail fuses were out, I'm thinking you would have worse problems than low volume. I also wonder of the volume pots are somehow inside your amp.

Did you compare your amp sound to your friends in your system? If not, your perception may also be resulting from your pre/pro setting.

If you run a dedicated outlet of 20A breaker and outlet to an Amp that has a 15A fuse, I`m quite sure you will blow the main fuse on the amp due to allowing 20A come through a 15A fuse.

. . . very funny.