I have an CSA 803C and I also have this Fan-problem and the Light.
The Fan in my instrument works fine for about 2 minutes after turning it on and after that it starts beeing noisy.
I have now changed to a Noctua Fan (Noctua NFA12x25, PWM/FLX does not matter) which I really can recommend.
The air flow is good and it is wisper quiet to start with and gets a bit louder when the error hits the Fan so to say :o)
I have tried to remove the PSU but the cables are very short and entangled with the boards surrounding it and the
conectors are hard to reach, but I will try to give it a go some day.