SHARP FO-78
Service Manual

UX-68DE FO-78DE 3. Diagnostic items description 3. 1. Soft switch mode
The soft switches are provided so that each operation mode can be set by using the operation panel. In this mode, these switches can be checked and set. The contents of these switches are backed up. The available soft switches are SW-A1 to SW-K1. The content of soft switches is shown in page 2-5 to 2-18. The contents are set to factory default settings.

3. 6. Signal send mode
This mode is used to send various signals to the circuit during FAX communication. Every push of START key sends a signal in the following sequence. Moreover, the signal sound is also output to the speaker when the line monitor of the soft switch is on. [1] No signal (CML signal turned on) [2] 9600bps [3] 7200bps [4] 4800bps [5] 2400bps [6] 300bps (FLAG) [7] 2100Hz (CED) [8] 1100Hz (CNG) [9] Pseudo Ring (models with auto TEL/FAX changeover function) [10] END

3. 2. ROM & RAM check
ROM executes the sum check, and RAM executes the matching test. The result will be notified with the number of short sounds of the buzzer as well as by printing the ROM & RAM check list. Number of short sounds of buzzer 0 � No error 1 � ROM error 2 � RAM error (32Kbyte)

3. 7. Memory clear
This mode is used to clear the backup memory and to reset to the factory default settings. The content of each setting will be cleared. Note: Be sure to execute the memory clear mode whenever you change the country select setting. The default settings of the soft switches vary according to the destinations. Therefore, if you do not execute the memory clear after changing the country select setting, some functions may not work.

3. 3. Aging mode
If any document is first present, copying will be executed sheet by sheet. If no document is present, the check pattern will be printed sheet by sheet. This operation will be executed at a rate of one sheet per 5minutes, and will be ended at a total of 10 sheets.

3. 4. Panel check mode
This mode is used to check whether each key operates properly or not. Press the key on the operation panel, and the key will be displayed on the display. Therefore, press all keys. At this time,finally press the STOP key. When the STOP key is pressed, the keys which are not judged as "pressed" will be printed on the result list. � LED part of the contact image sensor (CIS) is kept on during the term from when "START" of the panel test mode to end with the STOP key.

3. 8. Shading mode
The mode is used for the shooting compensation. For reading, set up the special original paper. The shooting compensation memorizes the reference data of white and black for reading. Moreover, the memorized data is not erased even if memory clear mode is executed.

3. 5. Check pattern
This mode is used to check the status of print head. Two sheets of check pattern are printed. The following information of check pattern is printed.

3. 9. All black print
This mode is used to check the state of the printing head and intentionally overheat it. Whole dots are printed over the interval of 2 m. If it is overheated or the printing sheet is jammed, press STOP key for the end.

1 Vertical stripes (alternate white and black lines) Approx. 35 mm 2 Full black Approx. 70 mm 3 Full white Approx. 35 mm
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3. 10. Auto feeder mode
feed function.

In this mode, a document is inserted and discharged to check the auto After this mode is started, set a document, and the document feed will be automatically tested.

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RANK 0 or 1

Note: There is a selection RANK 0 or 1 depending on resistance value of the thermal head. RANK 0 or RANK 1 is printed at the tail of check pattern to identify.

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