C2557 (bizhub 950i/850i)
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Contents
| Trouble type | C2557: Abnormally low toner density detected black TCR sensor |
| Rank | B |
| Trouble detection condition | When sampling data is determined in TC ratio calculation control, TCR sensor output is lower than a predetermined value for a predetermined number of times in a row even though there is toner in the sub hopper. |
| Trouble isolation | – |
| Relevant electrical parts | – Developing unit – Toner cartridge – Toner empty sensor/K (PZS/K) – Toner supply motor/K (M12) – Toner cartridge motor/K (M14) – CPU board (CPUB) – Base board (BASEB) |
Procedure
- Perform image troubleshooting procedure if image density is low.
- Check the connector between M12-relay CN258-BASEB CN18E for proper connection and correct as necessary.
- Check the connector between M14-relay CN321-relay CN428-BASEB CN19E for proper connection and correct as necessary.
- Check the connector of M12 and M14 for proper drive coupling and correct as necessary.
- Check the connector between PZS/K-relay and CN253-BASEB CN27E for proper connection and correct as necessary.
- Check CPUB for proper installation and correct as necessary.
- PZS/K I/O check, sensor check
- Control signal: BASEB CN27E<A>-11 (ON)
- Location of electrical component: 15-C
- M12 load check (There must be no developing unit and drum unit installed.)
- Control signal: BASEB CN18E-15 to 18
- Location of electrical component: 14-K
- M14 load check
- Control signal: BASEB CN19E-1 to 4
- Location of electrical component: 2-K
- Replace M12.
- Replace M14.
- Reinstall the developing unit.
- Reinstall the toner cartridge.
- If the toner empty sensor and its surroundings inside the sub hopper are dirtied with toner, clean them.
- Replace the developing unit.
- Replace CPUB.
- BASEB F7E conduction check.
- Replace BASEB.