Mackie Snap crackle and pop

[Joe Soap]

Hi all you bods, I have a Mackie SRM 450 V2 with a supply section (I think) problem.
The beast switches on ok and sounds perfect, however, within a minute or so it starts popping and fizzing and eventually switches itself off.
Has anyone any experience of this? I have the schematics so can anyone point me in the right direction to locating the fault?
I had a similar problem on an Engl Screamer which i eventually traced to a dodgy resistor - not quite so straight forward with switched power supplies and the dreaded surface mount micro components...

Thanks in advance.

Joe

[Jazz P Bass]

Can you determine what is 'popping & fizzling'?
Is it the power supply or the amplifier itself?
(Divide to Conquer)
With SMPS there is usually a feedback path in the supply.
An overload can shut it down, as well as a failure in the supply itself.
"Has anyone any experience of this".
Unfortunately, the failure mode of any amp requires troubleshooting.

[Joe Soap]

Can you determine what is 'popping & fizzling'?
Is it the power supply or the amplifier itself?
(Divide to Conquer)
With SMPS there is usually a feedback path in the supply.
An overload can shut it down, as well as a failure in the supply itself.
"Has anyone any experience of this".
Unfortunately, the failure mode of any amp requires troubleshooting.

Thanks for that P Bass

I'll try isolating the power stage and work my way up.

Regards.