move the lever and watch where it pivots, there's a roll pin holding it, see pushed out here - not sure if that'll get the diaphragm free on your model, never messed with one, but if not you might be able to peel up one edge of it and get a peek

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature we find it attached to the rest of the world" John Muir
"When we tug a single thing on an old truck, we find it falls off" me
Some TF series details & TF heater pics & Rust-a-holics Unanimous parking lot