Sharp MD-MS200W Service Manual page 17

2
E -PROM (IC402) writing procedure
1. Procedure to replace E
2
(1) Replace E -PROM.
2
(2) Deprive E -PROM of protection (connect the pins 8 and 2 of IC402).
(3) Refer to the latest E
(4) Press the Display/Lower-case Character button, Enter/Synchro button and Play/Pause button to start the test mode.
(5) Version display
[ V e r .
(6) The whole LCD lights.
(7) Test mode stop state
[ T E S T
(8) Press the Enter/Synchro button.
[ E E P R O M ]
(9) Perform the operation to display "E
display, and set according to the E
(10) Set the temperature reference. (Refer to the Temperature Reference Setting Method.)
(11) Set according to the E
(12) Press the Stop button.
[ T E S T
(13) Press the Stop button.
(14) After data is written in E
(15) Restore protection of E
2. Temperature reference setting method (to be performed at room temperature 21 to 29 C)
(1) Test mode stop state
[ T E S T M O D E ]
(2) Measure voltage of TEMP terminal (pin 3, IC401) of microcomputer.
(3) Calculate the temperature reference, using the following formula.
Temperature reference =
(4) Round down decimal fractions of calculated temperature reference, and convert it to hexadecimal value.
(5) Correct the temperature according to the table below depending on ambient temperature.
Ambient temperature
21 - 23
24 - 26
27 - 29
An example: Environmental temperature is 22 C and set voltage is 1.25V.
Temperature reference =
(6) Press the BASS button, and press the SKIP DOWN button.
[ E E P R O M ]
(7) Press the PLAY button, and press the SKIP button.
[ T e m p
(8) Press the PLAY button.
[ T E M P
(9) Set the temperature standard value to the value obtained above with the VOL UP and VOL DOWN buttons.
(10) Press the STOP button.
[ T E S T
2
-PROM and write initial value of microcomputer in E
2
-PROM data list.
]
E 2 -PROM version (C ~ Z)
Microcomputer ROM version
]
2
-PROM SETTING MODE CHART", compare the E
2 -PROM DATA LIST with the VOL UP or VOL DOWN key.
2 -PROM DATA LIST.
]
2 -PROM, turn off power .
2
-PROM (Disconnect connection made in Step (2) above).
Measured voltage x 256
Temperature correction
+ 1
0
- 1
1.25 x 256
= 114.286
= 114 (Decimal fraction is rounded down.)
= 72 (Conversion to hexadecimal value)
H
]
]
]
MD-MS200W/MD-MS200/MD-MS200H
2.8
2.8
: Temperature reference
– 17 –
2
-PROM
2
-PROM DATA LIST with the