I am looking at buying a vintage Peavey Series 400 Amp. The seller says that there is a hiss, which he believes is a bad capacitor. I have not looked at it yet. I am hoping to check it out this weekend. Anyone have any insight on typical problems associated with this amp. I am curious what it might cost to repair. The deal is the amp, the original pedal, and a Peavey 410S cabinet for $225.00, as is. Thanks.