Film cameras
Mamiya 7 battery
1 × 6V silver oxide cell
The Mamiya 7 manual allows one 4SR44 silver oxide, 4LR44 alkaline, or 2CR1/3 lithium. PX28 is the common retail silver-oxide label. Camera will not function without a cell.
How to replace it
| How to open | Remove the battery chamber cover on the bottom with a coin or screwdriver. Insert the 6V cell with (+) facing the cover as marked, then reseat the cover. |
|---|---|
| Orientation | + side up, facing the battery chamber cover |
| Access | Coin or simple twist |
| Notes | Camera will not function without a battery. Prefer silver-oxide 4SR44/PX28 for meter behaviour when available. |
Important
- OEM allows 4SR44 (PX28), 4LR44 alkaline, or 2CR1/3 lithium — chemistry differs; do not assume identical meter behaviour.
- Not a 1.35V PX625 mercury cell.
- Keep photo cells away from children.
Sources
Helpful for this device
Optional tools for opening, testing or charging — separate from the battery answer.
- iFixit Opening Picks
Non-marring opening for tool-free / clip housings
- Fluke 101 Digital Multimeter
Accurate open-circuit voltage and basic electrical checks
- Digital multimeter
Measure open-circuit voltage and general electronics checks
New battery but still not working?
A fresh 1 × PX28 should restore Mamiya 7 if the battery was the problem. Work through the checks below before replacing the device.
- Check orientation
Confirm the cell is seated correctly: + side up, facing the battery chamber cover
- Check the battery type
This device needs 1 × PX28 (silver_oxide). Rechargeable cells are not supported for this device. Same size does not always mean the same battery.
- Check known model-specific issues
OEM allows 4SR44 (PX28), 4LR44 alkaline, or 2CR1/3 lithium — chemistry differs; do not assume identical meter behaviour. Not a 1.35V PX625 mercury cell. Keep photo cells away from children.
- Confirm the battery itself
Try a known-good fresh cell of the exact code listed above.
- Still not responding?
If a correct, fresh battery installed properly does not restore the device, the fault may be elsewhere — the device may need service or replacement.