Now the keys and the peg board that hold the keys are off you can see the couplers. These are little levers that can connect one key to two notes. When you press one key two will be depressed when the couplers is engaged using the relevent stop.
In our case the treble and bass coupler are on one piece of wood so need to be removed together. A few screws and some very gentle pulling and tipping and the couplers are out.
This is all going to need a good clean. The levers seem a little stiff which is a concern. Also it looks like each piece is held in by two hooked pins which may be hard to service. I guess I don’t want to disturb these too much. Have to have a think.