Does anyone work on B500B Amps out there???

[BoWeevil]

Hey guys,
I picked up what I was told a gently-used B500B on eBay, but when it arrived and I got around to powering up, it is having some distinct issues.
The Low "A" Channel seems to have some weird noises as you turn the potentiometer, almost like there is an issue with load applied that finally dissipates when the pot is wide open.
The High "B" Channel is distorting, even at very low input and output levels.
I acquired the schematics from MarshallJMP, but this way over my head.
Is there anyone out there that would work on this and get it working for me?
I'm in Southern Ohio, so would prefer to keep it here in the States if at all possible.
Thanks and looking forward to your replies,

[rnolan]

Hey BoWeevil, Since you have the schematic, any decent tech should be able to work on it for you, they are not super complicated amps. Ask around you music shops or hi fi shops for who is good.  While they have it apart, it would also be a good idea to get them to re-flow the whole amp (re melt all the solder joins).  Also one thing MikeB discovered changing the jacks on his B200s was it does matter to have insulated sockets (ie don't conduct with the amp case), he initially put in normal jacks and got a hum and had to use the non connecting type.  If it needs parts your tech can't find (hopefully not) MJMP may be able to help ?

[rnolan]

BTW did you get the fan sorted out on the other B500B ?