Hey Kevin,
Welcome to the group. Start by grabbing the sevice manual, which can be found online. Here < > is one place. Give it a read, take a deep breath, then dive in to diagnosis and repair. These old service manuals are amazing.
Now, I don't have a scope from this era myself, but I understand the transistors may be socketed. This may help as it's easy to pull them out for testing, and to swap them around.
Do you have access to a second scope for troubleshooting?
Siggi
