Self Diagnostic Function - Sony CPD-G400 Training Manual

The front panel combination green/orange LED is used to indicate the following:
• Loss of input sync (see Power Saving Modes)
• Failure in the High Voltage and Vertical Output Stages
• Excessive ABL current (picture tube or drive failure)
The following chart shows the LED indications and what level of voltage at CPU IC1001 will activate (enter) this protection mode. Once the trip voltage
is exceeded, the CPU enters the Active Off power mode and remains latched in this state until you press the power button to reset the CPU.
Indication
O nly the G reen LED blinks at
about 2 H z.
Both LED s are dark. PS beeps @
2 H z.
Both LED s blink at 1 H z.
Both LED s O N = 2 sec. O FF = 1
sec
Both LED s blink O N = 1 sec,
O FF = 2 sec.
LED s alternately blink @ 1 sec
each
B+ Detection
B+ 200V is sampled by the CPU IC1001/pin 14, but the CPU is not pro-
grammed to respond. Perhaps this is because the monitor is well pro-
tected at the power supply itself where the power transformer's second-
ary is fed back directly to the control IC. A higher voltage will cause the
power supply control IC to momentarily stop the oscillator. The oscillator
will start again, causing the front panel green LED to cycle on, then off,
then on repeatedly as the power supply switches on and off. See the
Regulating Circuit for details.
HV Detection
This monitor uses the Horizontal pulses from the DPU IC801 (N Board), a
regulating circuit and the FBT T901 to make HV. CPU IC1001/pin 16
monitors a winding of the flyback at T901/pin 8 for excessive voltage.
Excessive HV causes the CPU's Heater output voltage to be LOW, caus-

Self Diagnostic Function

Self Diagnostic Indication Function
D efective Stage Sensed at
IC 1001
B+ (200V) excess N /A
B+ shorted N /A
H V D etection Pin 16
V O utput / H O utput Pin 42
ABL (C R T current) Pin 17
N one Aging M ode
67
IC 1001 N orm al IC 1001 Trip
Voltage Voltage
N /A N /A
N /A N /A
2.8V 5.0V
3.3V 0.6V
5.0V 5.2
ing SCR D616 to trip the power supply into the Burst mode. In the Burst
mode, the power supply will just be able to supply enough energy to feed
the standby regulator IC609. The standby voltage keeps the CPU pow-
ered to keep the monitor latched in this Active Off power mode. A HV
triggered failure is identified when both green and orange LEDs turn on,
blinking on one second and off the next second. This blinking will con-
tinue until reset by shutting the monitor OFF or unplugging it from AC.
ABL Detection
The automatic brightness limiting circuit normally reduces the High Volt-
age when the CRT current is excessive. Excessive ABL voltage causes
CPU IC1001 to enter the low power Active Off mode for protection. An
ABL triggered failure is identified when both LEDs are turned on and blink
ON for one second and OFF for two seconds. Some possible causes are
shorted video driver IC004, G2 voltage too high, or a picture tube struc-
tural failure.
Pow er M ode Latched
PS restarts N /A
PS restarts N o
Active O ff Yes
Active O ff Yes
Active O ff Yes