Renovating gang switches

Confronted with a huge Rotel amp from mid 1970s. Function switch, interlinked S/R ganged switch, 5 gang, each of 4 pole 2 way with pins extending above and below and a pcb above and below . One failed switch contact. I'm surprised I've never had to break into one before, serious miultiway radio waveband switches , yes, but they are not ganged. This make of logo TMS in an elipse, hopefully applicable to other makes of ganged switches. How to get inside without desoldering all that lot. U channel steel between the 5 gangs has 4 nibs , bent over, to trap each gang , bend back those 4 and the next 4 along the gang strip to give some lee-way. Small blade between that channel and the sw body to lever and give enough gap to release the S/R interlink that runs inside the U channel , and in this one release a nylon limit widget , from under the spring and then the core of the gang simply slides out. In this case aged/compacted grease had wedged the phosphor-bronze contact away from ever making contact