Panasonic KX-F900 Service Manual page 62

[..... Kx-Fgoo .... ]
The graphs below show you the wave form that is observed when unit (board) doesn't work. (A3 is intentionally opened at
pin 135 of ASIC in this board.)
Please check that active (low level) term of ROMCE is longer than good wave form, **ROMCE is active (low level) except-
ing RESET is active.** and RESET is frequently coming on every 4 msec.
In the case of this wave form ASlC (ICl), ROM (102) or on the way of bus line route is possibly defect. If soldering, con-
ductance is no problem, we need to replace these ICs.
CH 1 5V/div
CH2 5V/div
CH3 5V/div
CH4 5V/div
Wl 500ns/div
Length 100
W2 51_s/div
A Length lk
;sampling Normal
20Msps
Marker 1
T 9_,.651_
V
Marker 2
AT -2.15p.s
l/AT
465. lk Hz
AV
0.2 V
Time
Time Base I Roll
I off
'1'Trigger _" CH1/2 z_ MEM1A MEM2
H1 W1
10.0V_ A0
DO
: i :
i i RoMcs _ :
........ i ........ :: ........ i ..................... r_!iongi ........ i........ i ...... :
4
i i ! : i
RDi i
I
Time/div
Wl
lime Base
External
NG
CH1 5V/div
CH2 5V/div
CH3 5V/div
CH4 5V/div
Wl 1ms/div
Length 100
W2 10ms/div
Length 1k
Sampling
Normal
10ksps
Marker 1
T 576.5ms
V 4.8 V
Marker 2
T 15.0ms
V 0.2 V
AT -561.5ms
l/z_T
1.781 Hz
AV -4.6 V
Time
Time__Base I
tTrigger _CH1/2 AMEM1 &MEM2 Time/div
H1 Wl o Wl
10.0V_ i A0
ili ii! i--; .......................................
• ..... . W2 '_l_4=l_
: Time Base
DO ;
_:i i'i ...... _ "'_" !i'"'_ _: "'i' i_ External
RO_ICS
::: ...... ::' ]oo::10ngi =................................. _: NG
: Ft$_ :
-40.0V
575.0ms i 585.0ms
o":t I I I I
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