Looking for repair service for EAR preamp


I have an EAR 864 preamp (an old timer!) with the integral phono stage. The line stage section, which utilizes two tubes, has developed a crackling sound in the right channel after the unit has been on a while. I've tested the tubes and even exchanged them to be sure, but the problem persists. 
I have tried to contact Dan Meinwald at EAR USA for a recommended service facility but he has not responded. In the past he was always quick to reply and forthcoming with information. I hope all is well there.
Bob Backert serviced my EAR 868 not too many years ago but he has become quite busy building his preamps and apparently is no longer taking repair work.
Can anyone on this forum suggest a reliable service technician who would be willing to fix this wonderful old preamp?
Many thanks in advance for your suggestions,
Fred
fred_s
Thanks to all of you (bdp24, steakster, and lowrider57) that sent recommendations for EAR products repair.
I am keeping a record of these for future reference.
Since I live in southern New Jersey, the northern NJ reference will be the first to contact. 
Also, thank you to noromance for the clever tip for pin pointing a cold solder joint. Since this preamp has been repaired twice that I know of, this is a good place to start the troubleshooting.
In my local audio group, there are 3 of us who use EAR components. We are big fans!
Thanks again to all,
Fred
Sounds like a heat-related problem. If you buy a can of electronics freezer, you can localize the fault by spraying it on specific components until you get it nailed down. Probably a solder joint.
On the east coast Ben Jacoby at High End Audio Repair does factory authorised service for EAR.
Thanks to Ben my EAR amp is running at better than factory specs.

Mitch Singerman specializes in EAR repair. 310-823-5145  in Los Angeles.  Don't know if he's still there.
Try Tom Carione at Brooks Berdan, Ltd. in Monrovia, California. He knows tubes very well, and has done lots of work on ARC, VTL, Jadis, Music Reference, McIntosh, etc. He's in the shop on Wednesdays and Saturdays.