One small comment;
- - are you checking your headers from the FRONT Panel - to the Main PCB?
Why?
When someone works inside the radio - especially these integrated head types like RCI does - the sheer number of headers, jumpers and sockets they all go in, can be easily overwhelming for a newbie starting out on this.
So if you haven't already, at least in the future - take pics using your phone or a simple digital camera so you can see and review before and after the works done - so you can make sure you got it put back together right.
I said the above, because for this problem to isolate to just AM may mean a cracked solder joint on the main PCB - onto a MODE switch header line it's open - not making the right connections.
So that might mean a header is not; properly seated, or all it's pins; making proper contact, on the board.
It's not "just" a "bad part" issue, it may be from the pulling-seating and all the work done - that did this.
The other low volume issue deals with MOSFET's that are used as switches to turn on the Ground needed to make the particular speaker and it's output jack work. IF you owned an RCI 2950/70 from a given year onto present...
On top of...So many different RCI models using the same outline - the boards changed to suit the newer technology and did away with from the older parts, but still give you the "same radio wrapper" - which adds to this whole mess of identifying the right board at the right time...
What am I talking about? See below...
So Ad Infinitum and Ad Nauseam...
