Peavey pops on shutdown

[ShoemanGB]

I'm getting a loud pop when I power down the Peavey Bandit.  I've attached a snip of the PS.  What should I be looking at as the cause? 

[PRR]

> What should I be looking at

Usually the power amp. You cut that part off the image.

[ShoemanGB]

Thanks Paul,  here's that section. 

[Latole]

Did you find the issue ?

Sometime it is the On/Off switch's contact

[ShoemanGB]

It seems to have cured itself. Currently it is operating as a power amp for a Tech 21 PSA 2.0 quiet happily.