Isdn Board Ng - Oki OKIFAX4550 Maintenance Manual

4.4.3 ISDN Board NG (03)

3: ISDN Board NG (03)
Check CN1 solderling.
Good
Check appearance of
G4N board.
Good
Waveform of pins 51, 50,
27 of RAM3 are similar
to Figure H.10(1/3).
Yes
Waveform of pins 1, 6, 7,
17 of RAM3 are similar
to Figure H.10(2/3).
Yes
Waveform of pins 51, 46,
45, 27 of RAM3 are similar
to Figure H.10(3/3).
Yes
Replace CPU chip.
Bad
Replace G4N board.
41309401TH Rev.4
MUPIS I/F initial sequence couldn't be
completed during 10 seconds.
Bad
Re-solderling
Bad
Modify bad point
No
Replace CN1 solderling
No
Replace RAM3
No
Replace RAM3
Good
Cause is CPU chip failure
563 /