Pentax 645 repair & common faults
Excellent coverageThe Pentax 645 was Pentax's first medium format SLR, launched in 1984 with a built-in motorised film advance and aperture-priority auto exposure. It runs entirely on battery power, so its electronically governed shutter and SPD metering are the two systems that decide whether the camera works at all.
Aperture-priority and manual auto exposure · electronically controlled vertical metal focal-plane shutter · SPD metering · 6V, 4×AA · Pentax 645 bayonet mount
Common Pentax 645 faults
Pentax 645 won't fire
Because the shutter is electronically timed rather than mechanical, a dead or intermittent fire almost always points to power delivery rather than the shutter blades themselves, most often corrosion at the battery contacts. Worth swapping in a fresh, known-good set of batteries first. If it still won't wake up, the fault sits deeper in the electronics and needs a proper look on the bench.
Pentax 645 meter reading wrong or erratic
An unstable or clearly wrong meter reading on this body usually traces back to the SPD cell's supply or ageing contacts rather than the cell failing outright. It tends to drift rather than die suddenly, which is why it often goes unnoticed until a roll comes back badly exposed. Check the batteries are fresh and seated properly before assuming the meter itself is at fault.
Pentax 645 LCD blank or missing segments
The top-plate LCD on these bodies is a known weak point simply from age, segments fade, go patchy, or disappear entirely well before anything else on the camera gives up. It is a display fault, not a sign the exposure system underneath is compromised, though a totally dead display can make the camera hard to use with confidence. A battery swap is worth ruling out first.
Pentax 645 uneven exposure across the frame
A frame that's darker at one edge, particularly at faster shutter speeds, points to the vertical metal curtains no longer travelling in sync, sometimes called capping. It's a mechanical timing issue in the shutter itself rather than anything to do with metering or batteries, and it tends to worsen with use once it starts. There isn't a no-tools check for this one.
Pentax 645 motor drive not advancing film
The built-in motorised advance is a mechanical and electrical system in one, so a wind that stalls, stutters or does nothing can come from the motor, its gear train, or the power feeding it. Confirm fresh batteries and that the film is loaded and seated correctly before assuming a fault. A motor that runs but doesn't move the film is usually a gear or clutch problem inside.
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Try it now ›Scatto is a reference tool for people who service film cameras. It explains mechanisms and quotes service data, but it cannot see your camera at the bench, so verify anything load-bearing before you act on it.