Audio Research D240 Service Manual

I have a D240 MKII that has started to show its age - when it is first turned on my speakers produce a buzzing noise for a few seconds. The noise usually fades away completely, but sometimes it persists at a low level. I've been trying to track down a service manual so I can have a tech friend of mine help me with it, but I haven't been able to find one. I spoke with Audio Research on the phone, but I was told all they could send me was the owner's manual. The tech was very friendly and offered their services to repair the amp, but I'd prefer to have it done locally if I can. I've tried to find something posted in a few places like and the ARC Database without any luck. Does anyone know where I can find a service/tech manual for the D240?
Well you should know there are no service manual's for ARC products. Circuit diagrams are only supplied to authorized warranty repair stations.