Juergen

Film Type 600 is a high speed film (600 ASA) used in Series 600 Cameras while Model 1000 and its cousins One Step and The Button are built to work with lower-speed SX-70 Film (100 ASA). The speed mismatch causes severe overexposure - white pictures.

Actually the U-shaped spring is the one that lets the door latch engage with the body. It is located at the right side of the Roller Assy looking from behind the camera. Observe the way it mounts on a functional camere, it´s tricky to describe in writing. The metal part it activates is visible on Step 9 of the dismantlich pictures.

If you have a disfunctional Non-Folding Polaroid Camera (all models with square format use the same spare part) you can replace the torn "frog´s tongue" with a good one. The part ist held in place with a plastic retainer which can be unlocked from the insede. You see the locking tabs just behind the roller assembly. The most practical way is to remove the housing part from the roller assy by pushing it downwards beneath the rollers thus unlocking 2 metal tabs keeping the housing in place, thenmoving it forward away from the rollers. Then you can easily remove the Light Shield Retainer and excange the defetive one for a good unit. Reverse these procedures toremount the housing. Update: Further to my answer of jan 28 i found out that "impossible" https://www.the-impossible-project.com/ now offers replacement Light Shields of somewhat longer dimensions. This new part will protect the emerging pictures for any time the user deems necessary, it does not jump back at the end of the Ejection Cycle.