Vh Setting - Epson 440 Service Manual

4.2.2.3

VH Setting

The piezo-electric element used in each printhead unit has unique electrical characteristic and the electrical
characteristic of each printhead is measured at the production and each printhead unit is given with the ID
code. Therefore, this ID code is need to be stored in EEPROM on the main board when the following
service is made and the printer read this information to compensate the difference of characteristic for
printing control and an amount of injected in k is maintained at the specified level.

Replacing the printhead unit

Replacing the printer mechanism (the after-service unit comes with the printhead unit installed)
1. When replacing the part mentioned above, take a note of the ID code indicated on the unit as
below.

Printhead Unit:

Printer mechanism:
2. Re-assemble the printer.
3. Connect the PC to the printer and turn on the printer.
4. Execute "GWBASIC.EXE" from the adjustment program diskette and run "J90C00E".
5. Go to the main menu [SCREEN-4].
6. Input "1" to select "VH Setting" and press ENTER key.
7. At the next menu screen, input "0" as "M/C No." and press ENTER key.
8. Then next menu [SCREEN-5] appear on the screen, and input the ID code which you noted at the
beginning of this procedure.

VH ID Code format:
9. After inputting the ID code, the program returns to the main menu and you can continue to another
adjustments.

Timing to write the specified value to EEPROM: Upon pressing ENTER key after ID code
input.
Rev. A
Stamped at the side of the unit
Indicated on a label attached to the packing box for the after-service
unit.
st nd
*1 /2 digits (from left)
rd
*3 digit
th th
*4 /5 digits
WORK POINT
Figure 4-5. Head VH ID Indication
=Normal dot VH ID
=Drive frequency ID
=Micro dot VH ID
Chapter 4 Adjustment
4-7