Use Of Doctor Program For Camcorder - JVC GR-DVA10 Technical Manual

4.1.2 Use of Doctor Program for Camcorder

Doctor Programs have been widely used for stationary video decks, however, the function of the Doctor
Program is an obstacle to repair of the product, namely, it occasionally brings about secondary troubles if
the program data stored in the EEPROM mismatches the microcomputer program as mentioned
previously. Under the circumstances that most of stationary video decks are not backed up by service
support system software and there is no means to read and write data stored in the EEPROM's of them,
the only way to cope with mismatching between the microcomputer program and Doctor Program is to
replace the EEPROM with a new one conforming to the microcomputer program or to kill the Doctor
Program electrically (to remove the resistor or to add a resistor). Although it is easy to replace the
EEPROM, the manufacturer is burdened with severe inventory management of spare parts because it is
required to have a large stock of differently written EEPROM's to supply them properly to various
microcomputer programs.
No Doctor Program had been adopted for camcorders until quite recently, however, late camcorder
models such as the GR-DVL9500 series and after adopt the Doctor Program. Fortunately such the
camcorders don't need to replace the EEPROM's with those which proper data are written in, because
data stored in the EEPROM can be rewritten by means of the service support system software. In such the
case servicemen are required to pay careful attention to matching between the microcomputer program
and the EEPROM data including the Doctor Program.
4.1.3 Revision of Service Support System Software for Doctor Program
To rewrite camcorder's Doctor Program in the field and to avoid trouble caused by mismatching between
the microcomputer program and Doctor Program, the Service Support System Software is reexamined
and revised as follows.
Doctor Load
Fig. 4-1-2 EEPROM Utility window
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