"Thelonious"

Obtain new diaphragm or other parts from Ritchie in Massachusetts. Confirm you have enough fluid to fill model of compass. I am told that if you have an existing bubble, chances are good the cause is an aging diaphram. And of course the diaphram can be punctured by an act of clumsy stupidity--which happened to somebody I know.

Remove and save existing fluid, if clear. The diaphragm can be felt under the compass body, where it expands and contracts according to fluid temperature. And where you can accidentally stick a screwdriver into it if you are in such an all-fired hurry as the fellow I know. That's one way to empty a compass fast.

With fluid out, remove screws on plastic dome and set dome aside.

Remove compass card, which balances on a bridge captured by slots in the casing. Be careful of the delicate balance device attached beneath it, which keeps the card level.
Remove the screws of the lower internal assembly (seen on the cutting board in the picture) , which holds the diaphram (seen resting on compass) in place.

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Remove and replace the rubber diaphragm and reassemble compass.
Locate fill hole in side of compass and use turkey baster to insert fluid until full.


Eliminate the bubble by manipulation of the compass body to burp it, topping off with baster. This was easy in my case at ambient 60F. If the weather is hot, it is recommended to put the fluid in the refrigerator first.