41955801Th Rev.8 - Oki C7500n Maintenance Manual

1 An image is generally faint or the color is irregular. (Fig 5-2 A )
• Is the amount of toner low? (Is [Toner Low] indicated?)
Yes Refill toner.
M •
No Is regulated paper used?
No Use regulated paper.
M
• Yes Is the LED head lens dirty?
Yes Clean the LED head lens.
M •
No Are all items of the LED head assembly connected properly to the connection board (Y73
PWB) and engine board (K7N/K7V PWB)?
No Check the cable connection (between each LED head and engine board), then connect the
cables between the LED head and engine board properly.
M •
Yes Is +5V output to the following power connector pins on the connection board (Y73 PWB)?
+5V: Pin 1, 2, 3, 4, 5, 6
• Yes Is +5V output to the each LED head assemblies on the connection board (Y73 PWB)?
3 pin for YPOW connector : LED head assembly - yellow
3 pin for MPOW connector : LED head assembly - magenta
3 pin for CPOW connector : LED head assembly - cyan
3 pin for KPOW connector : LED head assembly - black
No Replace the connection board (Y73 PWB).
M
• Yes Check the cable connections, then replace the LED head assembly.
M •
No Check the cable connections, then replace the low-voltage power unit. Did the printer
recover?
Yes End.
M •
No Is 34V output to the power connector on the engine board (K7N/K7V PWB)?
+34V: Pin 12, 13, 14
No Check the cable connections, then replace the low-voltage power unit.
M
• Yes Is 34V output to the HVOLT connector pin 2 on the engine board (K7N/K7V PWB)?
No Replace the engine board.
M •
Yes Check the cable connections, then replace the high-voltage power unit or belt cassette
assembly.
Yes End.
M •
No Is the I/D unit terminal connected properly to the contact assembly. (See Fig. 5-2)
No Connect the I/D unit terminal properly to the contact assembly.
M
• Yes Replace the image drum.
Note: 1. Remove EEPROM from the old board and set it on the new board upon replacing the
engine board (K7N PWB).
2. If EEPROM is not replaced, refer to section 3.2.2.
3. When replacing the engine board (K7V PWB), upload EEPROM data from the board and
then download it to a new board, using a life counter tool.

41955801TH Rev.8

Oki Data CONFIDENTIAL
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