Sony TRINITRON KV-27HS420 Service Manual page 9

Self-Diagnostic Screen Display
For errors with symptoms such as "power sometimes shuts off" or "screen sometimes goes out" that cannot be confi rmed, it is possible to bring up past
occurrences of failure on the screen for confi rmation.
To Bring Up Screen Test
In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:
DISPLAY Channel 5
Handling of Self-Diagnostic Screen Display
Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic screen during repairs. When you
have completed the repairs, clear the result display to "0".
Unless the result display is cleared to "0", the self-diagnostic function will not be able to detect subsequent faults after completion of the repairs.
Clearing the Result Display
To clear the result display to "0", press buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:
NOTE: This will also reset all user functions (including auto programming and picture settings)
Channel 8
ENTER
Quitting the Self-Diagnostic Screen
To quit the entire self-diagnostic screen, turn off the power switch on the Remote Commander or the main unit.
Self-Diagnostic Circuit
IC2300
MAIN MICRO
STBY -LED
STR
48
STBY -LED
44 OCP
45 OVP
43 LOW B ERR
5V
KV-27HS420/29DRC430/30HS420/32HS420/34HS420
Sound volume -
M
CLKO 29
DATO
30
AC RL Y 69
Q6527
Q6530
ENABLE ON
LATCH
Q6532
LATCH
A
IC504
SV REF
O I UNREG 7V
O
Power ON.
SELF DIAGNOSIS
2: +B OCP 0
3: +B OVP 0
4: VSTOP
5: AKB
6: LOWB
7: H-STOP 0
101: WDT 24
B
IC2801
Y/C JUNGLE
AKB
58 CRT
26 SCL
VPROT 35 VDY -
R5104
25 SDA
HPROT 34
R5125
RY6501
Q5018
P_SW(- )
1 2
INVERT
4 3
D
1K-PROT2
+B OVP UNREG 11V
D6537
D6505
HV PROT
D5007
KV-27HS420/29DRC430/30HS420/32HS420/34HS420
Numeral "0"
0
means that no fault was detected.
1
Numeral "1"
0
means a fault was detected one
time only.
R5105
B
D
2 IC5007 14
H. PROT
MONITOR
IC6505
+B OVP
PH6501
IN RUSH
+B
OVER CURRENT
4 1
3 2
R5013
+B
D
Q5004
+ B COP
D5005
DETECT
+B OCP
5V
Q6522
FOLLOWER
2
1
3
+B
9