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SF-7900(LX-522)
OCT. 1994
R
(with price)
SF-7900


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CONTENTS
SPECIFICATIONS ................................................................................................................ 1
TO REPLACE THE BATTERY ............................................................................................. 2
TO CHECK THE MEMORY CAPACITY ............................................................................... 2
ERROR MESSAGE ............................................................................................................... 3
TO RESET THE SF UNIT'S MEMORY ................................................................................. 4
TO SAVE THE DATA TO ANOTHER UNIT ......................................................................... 5
BLOCK DIAGRAM ................................................................................................................ 8
CIRCUIT EXPLANATIONS
System chart................................................................................................................. 9
Power supply circuit .................................................................................................. 10
CPU pin description (HD62076C03).......................................................................... 12
Gate array pin descriptions (SSC2571F0A) ............................................................. 13
Operation program ROM pin descriptions .............................................................. 14
RAM pin descriptions ................................................................................................ 14
DIAGNOSTIC OPERATION ................................................................................................ 15
TROUBLESHOOTING ........................................................................................................ 20
SCHEMATIC DIAGRAM
Main PCB .................................................................................................................... 21
Display PCB ................................................................................................................ 22
Key Matrix ................................................................................................................... 23
Key Matrix (Display side)........................................................................................... 24
PARTS LIST ........................................................................................................................ 25
ASSEMBLY VIEW .............................................................................................................. 27


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-- 1 --
SPECIFICATIONS
Main modes:
Telephone Directory, Business Card Library, Memo, Schedule Keeper,
Expense, Reminder, Calendar, Home Time, World Time and Calculator
Data storage:
Storage and recall of telephone, business card, memo, schedule, expense,
reminder data, calendar display, secret area; editing; memory status display
Clock:
World Time; reminder alarm; schedule alarm; daily alarm; accuracy under
normal temperatures:
±3 seconds average
Calculation:
12-digit arithmetic calculations; arithemetic constants (+, ­,
×, ÷); independ-
ent memory; percentages; square roots; 24-digit approximations; date calcula-
tions; other mixed calculations
General:
Display element:
16-column
× 8-line LCD
Memory capacity:
128kB (103436 bytes)
Main component:
LSI
Power supply:
3 lithium batteries (CR2032)
Power consumption:
0.07 W
Battery life:
Approximately 170 hours continuous operation in Telephone Directory;
approximately 130 hours repeating one minute of input and 10 minutes of
display in Telephone Directory; approximately 12 months for memory back
up
Auto power off:
Approximately 6 minutes after last key operation
Operating temperature: 0
°C ~ 40°C (32°F ~ 104°F)
Dimensions:
Unfolded:
9.55H
× 144W × 155D mm (3/
8"H × 5
11/
16"W × 6
1/
8"D)
Folded:
15.95H
× 144W × 77.5D mm(5/
8"H × 5
11/
16"W × 3
1/
16"D)
Weight:
124g (4.4 oz.)
· Design and specifications are subject to change without notice.
Current consumption:
Power switch
TYP. [
µA]
MAX [
µA]
OFF
11.7
37.1
ON
1,670.0
13,711.0
ON (Operating)
4,520.0
16,645.0


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-- 2 --
Hold down CAPA to display a screen that shows the current memory status. To clear the memory
status display, release CAPA .
TO CHECK THE MEMORY CAPACITY
Remaining memory
capacity
Total number of characters stored in memory
TO REPLACE THE BATTERY
To replace the batteries
1.
Loosen the screw on the back of the SF unit that holds the battery compartment cover in
place, and remove the cover.
Caution
In the next step, be sure to remove only one battery at a time.
Otherwise, you will lose all data stored in memory.
2.
Loosen the screw that secures one of the three battery holders
in place and remove the battery holder.
3.
Replace the old battery with a new one, making sure that the
positive (+) side of the new battery is facing up (so you can see
it).
4.
Replace the battery holder and secure it by tightening its screw.
Screw
RESET
+
CAPACITY
76420Bytes
27016Bytes
FREE
USED
0
100
50
26%


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-- 3 --
Message
Meaning
Action
DATA ITEM
Search operation
Current search operation
NOT FOUND!
attempted when no data
cannot be performed.
NO DATA
is stored in memory.
IN MEMORY!
DATA ITEM
Data specified in search
Change specification or
NOT FOUND!
operation does not exist
cancel search.
in memory.
MEMORY FULL!
No more room in memory Delete unnecessary data
for storage of data.
items from memory.
ALARM TIME
Attempt to set a Schedule Set a different alarm time
ALREADY USED!
Keeper alarm time that
or change the existing alarm
is already used for
time to another one.
another entry.
ALARM TIME
Attempt to set a Schedule Set a different alarm time
ALREADY PASSED!
Keeper alarm time for a
(for a future time/date.)
time/date that is already
passed.
SECRET DATA!
Alarm for a secret
Enter the secret memory
memory area data item is area to view details of the
sounding.
alarm.
PASSWORD
Attempt to enter the
Use the correct password.
MISMATCH!
secret memory area
using a password that
does not match the one
preset for the secret area.
TRANSMIT ERROR!
Error during data
Cancel the data
communications.
communications
STOPPED!
operation and try again.
DATA ERROR!
Data corrupted by strong
See page 11 of the
CONSULT THE
impact, electrostatic
owner's manual.
OWNER'S MANUAL!
charge, etc.
SAME TYPE
Attempt to store a label
Use a different label.
ALREADY USED!
that is identical to one
already stored.
ERROR MESSAGE