Mode Switching; Operating Voltages - Sony CPD-G400 Training Manual

Mode Switching

By using three operating modes to maintain the output voltages, the power
supply is more efficient. The correct operating mode is selected by IC603/
pin 14 for the Active Off Mode and maintained by using feedback from
transformer T602/pin 2. This signal is reduced considerably by R635 as
seen in the next waveform:
,
ch1: pkpk= 42.0 V
ch2: pkpk= 7.91 V
1
T
2
C H 1 1 0 . 0 V =
CH2 5.00 V~ MTB2.00us- 0.76dv ch1+
Name
Channel 1 Feedback
Channel 2 DEM
Time base

Operating Voltages

IC603 DC Voltages
Pin Normal Stby Mode
Mode
1 158V 165V
2 0 0
3 0 0
4 2.6V 0.06V
5 .02V 0
6 11.4-12.5V 9.1-9.7V
7 12.2V 9.1-9.7V
Mode Sensing
Location
T602/pin 2 (D613/A) 30Vp-p
IC603/pin 13 5Vp-p
2usec/div
Pin Normal
Mode
8 2.4V
9 2.7V
10 0
11 0
12 0
13 0.8-1V
14 5.2V
25
Line @ Location
200V @ D614/C
80v @ D618/C
15V @ D619/C
9V @ D620/C
9V @ D621/C
-15V @ D622/A
+ V @ D623/C &
D624/A
Forced Normal Operating Mode
If the power supply will not enter the Normal Operational mode (stays in
the Active Off / Burst Mode) this is because:
• There is a short on one of T602 or FBT secondary loads.
• Standby 5V is missing or CPU is defective.
Voltage
• SCR D616 is shorted.
• The regulating circuit is defective.
If you cannot find a short in one of the power supply loads or FBT loads,
you can force the power supply to enter the Normal mode. This is done
by:
• Disabling the HV for your own safety.
• Disabling the SCR on the +200V line.
• Turning ON the +5V and +12V regulators.
Stby A service manual to locate the parts, a jumper wire to force the power
Mode
supply into the Normal Power Mode and a 5V-power supply is needed to
turn on the regulators.
2.5V
0.06-0.2V
Warning - When repairing any electronic product, DO NOT PLUG THE
0
PRODUCT DIRECTLY INTO AC. Plug the product into an isolation trans-
0
former and the transformer into AC to reduce damage and the danger to
0
you when servicing.
0.07-.2V
5.6V
Power Supply Output Voltages
Normal/Light Mode
200V
77.5V
14.9V
8V
9.2V
-14.8V
+6.5V
Active Off Mode
16.5V
6.82V
1.07V
1.75V
13.5V for CPU
-1.2V
+1.1V