Sharp 34N-WF5H, Service Manual

Page: 9 / 87

9
34N-WF5H
3. Self-diagnostic Function (Protector Circuit Operation)
This model is equipped with five protector circuits. Shown below are the detections of the protector circuits and
possible trouble spots (outlined).
+130V line
FBT
+10V line +16V line
1
36
IC501 T630
4
7
10
R620
to FBT
Q750
Q782
Q3255
Q3224
Q781
C3231 C3230
D732
D731
D633 D790 D789
D786
D782 D781 D787 D792
D783 D772
D560
D582
IC3501
(DUNTKA140DE)
(DUNTKA096DE)
(DUNTKA163DE)
85 84
95
1
7
80
Q3208
A
CPO
W
Q3204
R
Y3701
(DUNTKA116DE)
Micom UNIT
Hor
iz
ontal
Protector
P
o
w
er Protector
Micro-processor
V
e
rtical Protector
Rela
y Dr
iv
e
A
C
Rela
y
A
C
Filter UNIT
Signal UNIT
Dr
iv
e
Dr
iv
e
IC3210
In
v
e
rter IC
+14V line
-14V line
IC770 (Chopper Regulator)
+6V line
+30V line
(VT line)
+28V line
(A
udio + B)
Dr
iv
e Circuit
P
o
w
er UNIT
Current AMP
.
Detection Circuit
A:
Detection
B:
P
ossib
le
T
roub
le Spot
1
Ov
er-Current Protector Circuit
A:
+130V line current detected (Flybac
k tr
ansf
or
mer r
ush current detected)
B:
•
Flybac
k tr
ansf
or
mer def
ectiv
e
•
Hor
iz
ontal deflection circuit tr
ansistor or diode
shor
t-circuited
•
Flybac
k tr
ansf
or
mer secondar
y-side rectifier circuit
par
ts shor
t-circuited or load circuit par
ts shor
t-circuited
2
X-Radiation Protector Circuit
A:
Flybac
k tr
ansf
or
mer ter
minal
0
v
oltage detected
B:
•
Resonance capacitor open
•
Hor
iz
ontal circuit open
4
Switching P
o
w
er Secondar
y-side under-v
oltage
protector circuit
A:
+10V
, +16V
, +28V
, +30V and 6V line v
oltages detected
B:
•
+B line rectifier circuit par
ts (diode
, capacitor)
shor
t-circuited
•
+B line load shor
t-circuited
5
Switching P
o
w
er Ov
er-v
oltage Protector Circuit
A:
+10V and +6V line v
oltage r
ise detected
B:
•
Switching po
w
er pr
imar
y-side circuit in troub
le
(causing v
oltage r
ise)
•
Chopper regulator malfunctioning
3
V
e
rtical Output Protector Circuit
A:
V
e
rtical output (pulse) monitored and no-pulse
condition detected
B:
+14V line circuit in troub
le
, causing v
oltage
drop (rectifier circuit par
ts shor
t-circuited)
or circuit open.