C2557 (bizhub 4750i/4050i)

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Trouble typeC2557: Abnormally low toner density detected black TCR sensor
RankB
Trouble detection conditionWhen 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 toner cartridge.
Trouble isolation–
Relevant electrical parts-Imaging unit/K
-Toner transport motor (M4)
-Toner supply motor (M5)
-CPU board (CPUB)
-Base board (BASEB)

Procedure

  1. Perform image troubleshooting procedure if image density is low.
  2. Reinstall the imaging unit.
  3. Check the connector between the imaging unit/K-relay CN6-BASEB CN14E for proper connection and correct as necessary.
  4. Check the connector between M4-BASEB CN11E for proper connection and correct as necessary.
  5. Check the connector between M5-BASEB CN11E for proper connection and correct as necessary.
  6. Check CPUB for proper installation and correct as necessary.
  7. M4, M5 operation check
    • Control signal: BASEB CN11E-1 to 4 (M4), BASEB CN11E-5 to 8 (M5)
    • Location of electrical component: 4-C
  8. Replace the imaging unit. IUP35K (Part# AAJV01D)
  9. Replace CPUB. (Part# ACT9H01003)
  10. Replace BASEB.
    4750i (Part# ACT9H02013)
    4050i (Part# ACT9H02002)

(Link to the Field Service Manual)