Hi Michael and welcome to JustAnswer,Thank you for the question and your patience. With the indulgence of Aric and should you still need assistance for information purposes only...Initially and it has to be asked; are you then considering a DIY (do-it-yourself) repair approach? If yes, do you have access to and familiar with a multi-meter and even a soldering iron?
Hi again Michael,
...to my recollection yes; have done work on the ASW series including the 855 but years ago.
Still, please post back with clear pictures of the inside circuitry particularly the power transistors attached to the big aluminum heatsink and the circuit board its legs are connected to.
The above pictures would then serve as a common reference when pointing out test points or a particular component.
Most multi-meter brands/models would serve the purpose but it would be to your advantage to get a model that has a built-in transistor checker. Please click HERE.