Mackie SRM450 trouble shoot amp section

"@clayt0n this is a tall order since you are talking about multiple devices with multiple errors. Pick one device and deal with the failure. That way you do not get confused by trying to many things at once. Use the test points on your circuit board to find faults or perform adjustments. Something like this for ""high frequencies from mid driver, scratch noise"" for example:

there is a bit more in the SM Mackie SRM450"

Hi maybe unrelated but I have Mackie c300z cabs they both failed .Are about 6 years old.thinking it was my amp I tried another on them and no wasn't the amp.stripped one down found the cones were solid no movement so had to rip cone out as I needed to rule out the amps.found the speaker coils jammed by the moved magnetics hence a write off so much for mackies speaker reputation as obviously is a build fault as they shouldn't move but they can not going to pay mackies exaubitent prices to fail again.