Output Voltage Adjustment - Sony DNW-A100 Maintenance Manual

3-1-2. Output Voltage Adjustment

When the power supply unit was repaired, perform the
adjustment (check) under disclosing the power supply unit.
c
Since the primary circuit is exposed, be extremely careful
with not to get an electric shock.
When completing the adjustments and checks, turn off the
POWER switch without delay.
Tools List
. Digital voltmeter: ADVANTEST TR6845 or equivalent
. Extension cable set (SONY part No. 1-957-071-11)
. Shorting clip
Preparation
1. Wait more than 30 seconds after turning off the
POWER switch.
2. Disconnect the power cord and all cables on connector
panel.
3. Remove the power supply unit.
(Refer to Section 5-30.)
4. Reattach a power supply panel assembly under staying
on the VTR's right side panel down.
(Do not reattach the bottom plate.)
5. Connect five connectors of the extension cable set to
each connector of the VTR's harnesses that were
connected to the power supply unit before.
6. Take a power supply unit to pieces as figure of right.
(Refer to the exploded views in Section 2 of the
maintenance manual part 2, volume-2.)
7. Reconnect the MAIN1 board and MAIN2 board with a
harness of the power supply unit.
8. Connect the five connectors of extension cable set to
the MAIN1 board and MAIN2 board.
n
Be sure to confirm that nothing is the cause of the
short circuit under the MAIN1 and MAIN2 boards.
9. Connect both GND of the MAIN1 board and MAIN2
board with a shorting clip.
10. Connect the power cord.
11. Wait for 10 minutes after turning on the POWER
switch.
DNW-A100/A50/A45
DNW-A100P/A50P/A45P
CN201
MAIN 2 board
VR2
VR252
VR1
VR251
SUB 2 board
Voltage Adjustment (Check)
Adjust and check each output voltage of power supply
lines at the following points.
Line Measurement point
+3.4 V CN151-1/MB-648(N-10) +3.40 ±0.20 V 1VR252/MAIN2
+5.1 V CN151-2/MB-648(N-10) +5.20 ±0.25 V 1VR1/SUB2
CN151-3/MB-648(N-10) +8.00 ±1.00 V Check only
+8 V
CN151-5/MB-648(N-10) _8.00 ±1.00 V Check only
_8 V
+15 V CN151-6/MB-648(N-10) +15.0 ±1.0 V
_15 V CN151-7/MB-648(N-10) _15.0 ±0.6 V
+12 V CN152-1/MB-648(M-10) +12.0 ±0.6 V
+2.5 V CN153-1/MB-648(Q-2)
+18 V CN201-1/MAIN2
3-1. Power Supply Line Alignment
3-1-2. Output Voltage Adjustment
VTR's bottom side
Extension harness set
Shorting clip
MAIN 1 board
VR253
Specification Adjust. point
1VR251/MAIN2
Check only
1VR253/MAIN2
+2.50 ±0.15 V 1VR2/SUB2
+18.0 ±2.0 V
Check only
3-3