Specifications

6.9 No Toner Cart or Toner Low

Explanation: The toner sensor circuit detects both the presence of a toner

cartridge and quantity of toner that remains.

The ac signal from the developer roller travels through the toner to the toner

sensor, which acts like an antenna. The strength of the signal received by the

toner sensor varies with the quantity of toner in the EP-ED cartridge.

The HVPSA measures the toner signal and determines the quantity of toner

or whether an EP-ED cartridge is installed. Toner is measured during the

development portion of the xerographic process. EP-ED cartridge checks are

performed during power up, after top door closing, or control panel keying.

Signal diagram reference: See Figures 6–5 and 2–11 for wiring diagrams.

Action: Do the following:

1. The toner might be damp. Remove the EP-ED cartridge and shake it to

loosen up the toner.

2. Swap the EP-ED cartridge with a known good unit.

3. Inspect the toner sensor contacts on the EP-ED cartridge and the connector

block. Replace any damaged parts.

4. Make sure the HVPSA is correctly installed. Both hold down screws must

be tight and the clips must be holding. See Section 9.4 for installation

instructions.

5. Remove the HVPSA and inspect the TB403 spring contact.

6. Swap the following FRUs:

• DC control board

• HVPSA

• HVPSA/Fuser Interconnect

• HVPSA contact plate guide

Power and Control Panel FIPs 6–13