There are a dozen versions of the main light switch. Only the first two have a blowup drawing and a list of parts and were originally intended to be repaired or overhauled. They were made by Bendix-Scintilla. The rest since them are throw aways. Yes some have snap rings allowing disassembly and some have crimped or otherwise sealed edges that do not lend themselves to disassembly. The two early style switches are illustrated quite well in your ORD 9 parts manual. Finding those small parts will be no easy chore.
To properly repair any of these switches will take patience and a knowledge of electrical repair techniques. The sliding contacts must be clean, smooth, and snug fitting. The very old wires connecting these contacts to the cannon plug will need to be replaced. Soft or broken springs will need replacement. And during assembly a special electro-insulating grease is used on the sliding contacts. Cleanliness is of the upmost importance during all of this.
If a functioning switch is your only need then I would go with the newest date of manufacture new switch I could find. This includes the current push button type switch that fits perfectly by the way.
Left to right are first Bendix, Second Bendix and early standard throw away.
Jos. Pollak unit.
Inside this is what you see. Note in the left photo at the top area there are dark tracks between the small round contacts and one contact is discolored. These are the tracks made by small copper particles that eventually pile up and cause shorting and overheating of the switch. These switches can be repaired but will often not last very long.
Here is the inside of the first style Bendix switch. This switch id clearly illustrated with a parts list in your ORD 9.
This is the latest push button style which will bolt right in.
