Troubleshooting By Symptom - Canon PIXMA MX870 Service Manual

2-4. Troubleshooting by Symptom

Faulty operation
Unsatisfactory print quality
Symptom
The power does not turn on.
The power turns off immediately after power-
on.
A strange noise occurs.
The LCD does not display properly.
A portion of the LCD is not displayed.
The display flickers.
Paper feed problems (multi-feeding, skewed
feeding, no feeding).
Faulty scanning (no scanning, strange noise).
No printing, or no color ejected.
Faint printing, or white lines on printouts.
Uneven printing.
Improper color hue.
(1) Confirm harness and connector conditions.
(2) Replace the following item(s):
- Logic board
- Power supply unit
- Panel board
(1) Examine and remove any foreign material or
paper debris.
(2) Replace the following item(s):
- The part generating the strange noise
- Logic board
(1) Confirm cable connection (LCD FFC and
panel harness):
- Harness and connector conditions
- No cable breakage, etc.
(2) Replace the following item(s):
- LCD FFC
- LCD viewer unit
- Panel board
- Logic board
(1) Examine and remove any foreign material or
paper debris.
(2) Confirm that the paper guides are set
properly.
(3) Confirm the PF rear cover and the cassette
conditions.
(4) Confirm cable connection.
(5) Replace the following item(s):
- ASF unit (for paper feeding error from the
rear tray)
- PF pick-up unit (for paper feeding error
from the cassette)
- DF unit (for document scanning error)
- PE sensor board
- Pressure roller unit
- Cassette unit
(1) Confirm cable connection (scanner motor
cable and CIS FFC):
- Harness and connector conditions
- No cable breakage, etc.
(2) Replace the following item(s):
- Scanner unit
- Logic board
(1) Confirm the ink tank conditions:
- Confirmation of the air-through of an ink
tank
- Re-setting of an ink tank
- Whether the ink tank is Canon-genuine one
or not
- Whether the ink tank is refilled one or not
(2) Remove foreign material from the purge unit
caps, if any.
(3) Perform cleaning or deep cleaning of the
print head.
(4) Perform print head alignment.
(5) Replace the following item(s):
- Print head
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Solution
*1
, and ink tanks