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Make sure that connecting cables, connectors and AC adapter are not loose or disconnected prior to 
testing.

YES

NO

1

1-1

Replace the FDD.
Does operation return to
normal?

Access lamp does not
light.

FDD

Go to No. 1-2

2

2-1

In the floppy disk warped or
bent, or labels interfering?

Cannot insert floppy disk.
Cannot remove floppy disk.

Floppy disk
FDD

YES

NO

3

3-1

Are there system files on the
media?

Does not boot from FDD.

Main PCB
Software

IC43

YES

NO

4

4-1

Is the floppy disk format
correct for the operating
system currently being used?

Cannot read from floppy
disk.
Cannot write to floppy disk.

Go to No. 4-2

Floppy disk format

YES

NO

5

5-1

Try cleaning the disk heads.
Does this fix the problem?

Floppy disk is scratched or
otherwise damaged.

Heads were dirty
FDD

YES

NO

6

6-1

Was the eject button pressed
while the system was
accessing the disk?

Content of floppy disk is
destroyed.

Operating mistake

Go to No. 6-2

YES

NO

6-2

Replace the FDD.
Does operation return to
normal?

FDD

Main PCB

IC43

YES

NO

7

7-1

Does this occur for a specific
floppy disk?

Damage to contents written
to floppy disk.
Damage to contents read
from floppy disk.

Floppy disk
Go to No. 7-2

YES

NO

8

8-1

Does it sound like the head is
moving?

Abnormal sound.

Normal

Go to No. 8-2

YES

NO

7-2

7-3

Replace the FDD.
Does operation return to
normal?
Replace the FDD FPC.
Does operation return to
normal?

8-2

Does the abnormal sound
stop when the motor stops
running.

FDD

FDD FPC

Go to No. 7-3

Main PCB

IC43

YES

YES

NO

NO

FDD

YES

9

9-1

9-2

Replace the FDD.
Does operation return to
normal?
Replace the FDD FPC.
Does operation return to
normal?

Diagnostic Test reports
problem in FDC.

FDD

FDD FPC

Go to No. 9-2

Main PCB

IC43

YES

YES

NO

NO

4-2

Does this occur for a specific
floppy disk?

Floppy disk
Go to No. 4-3

YES

NO

4-3

Try cleaning the disk heads.
Does this fix the problem?

Heads were dirty
Go to No. 4-4

YES

NO

4-4

4-5

Replace the FDD.
Does operation return to
normal?
Replace the FDD FPC.
Does operation return to
normal?

FDD

Go to No. 4-5

YES

NO

1-2

Replace the LED PCB.
Does operation return to
normal?

LED PCB

Go to No. 1-3

LD4

YES

NO

1-3

Replace the Main PCB.
Does operation return to
normal?

Main PCB

FDD FPC

IC43

YES

NO

FDD FPC

Main PCB

IC43

YES

NO

4 - 9

Make sure that connecting cables, connectors and AC adapter are not loose or disconnected prior to 
testing.

NO

1

1-1

Has the HDD been partitioned?

Does not boot from HDD.

Go to No. 1-2
Improper setting

YES

NO

2

2-1

Has the HDD been formatted?

Cannot read from HDD.
Cannot write to HDD.

Go to No. 2-2
HDD format

YES

NO

3

3-1

3-2

Replace the HDD.
Does operation return to
normal?
Replace the HDD cable.
Does operation return to
normal?

Replace the HDD.
Does operation return to
normal?
Replace the LED PCB.
Does operation return to
normal?
Replace the Main PCB.
Does operation return to
normal?

Damage to data written to
HDD.
Damage to data read from
HDD.
HDD contents are
destroyed.

HDD

Go to No. 3-2

YES

5

5-1

5-2

5-3

5-4

Has the HDD been
configured in the OS?

Access lamp does not
light.

Go to No. 5-2

Improper setting

YES

NO

4

4-1

Replace the HDD.
Does operation return to
normal?

Dignositic Test reports
problem in HDC or HDD.

6

6-1

Replace the HDD.

Abnormal sound.

HDD

2-2

2-3

Replace the HDD.
Does operation return to
normal?
Replace the HDD cable.
Does operation return to
normal?

HDD

Go to No. 2-3

YES

NO

1-2

Are there system files on the
HDD?

Go to No. 1-3
Software on the
HDD

YES

NO

1-3

1-4

Replace the HDD.
Does operation return to
normal?
Replace the HDD cable.
Does operation return to
normal?

HDD

HDD cable

Go to No. 1-4

Main PCB

IC43

YES

YES

NO

NO

HDD cable

Main PCB

IC43

YES

NO

HDD cable

Main PCB

IC43

YES

NO

HDD

Main PCB

IC43

YES

NO

HDD

Go to No. 5-3

YES

NO

LED PCB

Go to No. 5-4

LD5

YES

NO

Main PCB

HDD cable

IC43

YES

NO

7

Hard disk failure

Does executing FDISK
correct the problem?

7-1

HDD cable

YES

Main PCB

NO 

IC43

Go to No. 7-2

NO

Format data
destroyed

YES

Replace the HDD.
Does operation return to
normal?

7-2

Go to No. 7-3

NO

HDD 

YES

Replace the HDD cable.
Does opration return to
normal?

7-3

4 - 10

Make sure that connecting cables, connectors and AC adapter are not loose or disconnected prior to 
testing.

HDD cable

YES

Main PCB

NO IC43

8-2

8-3

8

Format data
destroyed

Does executing FDISK
correct the problem?

YES

Go to No. 8-2

NO

8-1

An operating system could
not be found

HDD 

Replace the HDD.
Does operation return to
normal?
Replace the HDD cable.
Does operation return to
normal?

YES

Go to No. 8-3

NO

1-2

Is the same transmission
protocol set for both the
sending and receiving units?

YES

YES

NO

NO

1

Data cannot be sent or
received.

Unit will not communicate
with another computer
when connected directly.

Does the RS-232C on the
Main PCB operate normally
under a loopback test?

1-3

Is the connection cable a
dedicated cross-patched
cable?

2-1

Is the same transmission
protocol set for both the
sending and receiving units?

2-2

1-1

Is the COM port properly
set?

YES

Go to No. 1-2

NO

Improper setting

2

Unit will not communicate
with modem.

3

Diagnostic Test reports
problem in serial port.

4

Go to No. 1-3

Check the
interface with the
other computer

Main PCB

IC47
IC48

Improper setting

YES

NO

Go to No. 2-2

Connection cable

YES

NO

Go to No. 2-3

Improper setting

Is the COM port properly
set?

3-1

YES

NO

Go to No. 3-2

Improper setting

YES

NO

Does the RS-232C on the
Main PCB operate normally
under a reverse test?

2-3

Check the
interface with the
other computer

Main PCB

IC47
IC48

Is the trasmission protocol
correct?

3-2

YES

NO

Go to No. 3-3

Improper setting

Does the modem operate
normally under a local
analog loopback test?

3-3

YES

NO

Line

Go to No. 3-4

Does the RS-232C on the
main board operate normally
under a loopback test?

Is the loop back device
properly attached to the
connector (for an external
loop back)?

3-4

4-1

YES

YES

NO

Modem

Main PCB

Main PCB 

NO

Improper setting

IC47
IC48
IC47
IC48

4 - 11

Make sure that connecting cables, connectors and AC adapter are not loose or disconnected prior to 
testing.

1

Data does not print from
the printer.

1-1

Does the printer pass its
self-printing test?

YES  Main PCB 

IC47

NO

Printer

2-2

Is the Parallel Port (Data
Direction) setting correct?

YES  Main PCB 

IC47

NO

Improper setting

2

Data prints out incorrectly.

2-1

Does the printer pass its
self-printing test?

3

The unit hangs after
outputting data from the
printer.

3-1

Replace the Main PCB.
Does operation return to
normal?

YES

Go to No. 2-2

NO

Printer

YES  Main PCB 

IC47

NO

Printer

4

Print area is out of line.

4-1

Does the printer pass its
self-printing test?

YES  Main PCB 

IC47

NO

Printer

5

Data is printed all on one
line.
(Carriage return does not
work.)

4-2

Does the printer pass its
self-printing test?

YES  Main PCB 

IC47

NO

Printer

Make sure that connecting cables, connectors and AC adapter are not loose or disconnected prior to 
testing.

1

Data cannot be sent or
received.

1-1

Is the Infrared Communica-
tion Port enabled in Setup?

YES

Go to No. 1-2

NO

Improper setting

2

Transmitted data becomes
corrupted.

2-1

Is the transmission distance
within 20-50 cm?

YES

Go to No. 2-2

NO

Use within
specified distance

2-2

Is the transmisson path
clear of obstacles and
interference?
Is the unit operated away
from TV sets, video, wireles
headphones, incandescent
lamps or other electronic
equipment?
Is the unit operated away
from direct sunlight?

YES  Main PCB 

IC47

IC770

NO

Change operating
environment

1-2

Is the same transmission
protocol set for both the
sending and receiving units?

YES

Go to No. 1-3

NO

Improper setting

4 - 12