Section 3: Safety Related Adjustments; Preparation Before Confi Rmation; 3-1.1 Hold-Down Operation Confi Rmation; B+ Max Confi Rmation - Sony TRINITRON KV-27HS420 Service Manual

3-1. PREPARATION BEFORE
CONFIRMATION
Standard............................................................................. 135.3 ± 1 VAC
Check Condition:
AC input voltage: 120 (± 2) VAC
Note: If using a stabilized power supply, make sure that the distortion
factor is 3% or less.
Setting Mode: ............................................................................ Full mode
Signal Input: ............................................................Cross-hatch of NTSC
Initial Setting:.....................................................Standard Reset condition
Confi rm Point:..........................Across CN5509 PIN 9 for B+ of DZ Board
3-1.1 HOLD-DOWN OPERATION
CONFIRMATION
1. Using an external DC power supply, apply 5.3 ± 0.5 Vdc between
Pin 2 of CN507 (jig connector) and ground (Pin 8); confi rm set goes
to hold-down (main power relay click).
2. Remove the external DC power supply.
3-2. B+ MAX CONFIRMATION
Standard 135.3 ± 1 VAC
Check Condition:
AC input voltage: 120 (± 2) VAC
Note: If using a stabilized power supply, make sure that the distortion
factor is 3% or less.
Setting Mode: ............................................................................ Full mode
Signal Input: ............................................................Cross-hatch of NTSC
Initial Setting:.....................................................Standard Reset condition
Confi rm Point:..........................Across CN5509 PIN 9 for B+ of DZ Board

3-3. B+ VOLTAGE CHECK

Standard:..........................................................................135.3 ± 1 VDC
Measurement point:
CN5509 pin (9) for B+ of [DZ] board
Input Video Signal:............................................................All Black Signal
Picture level:..................................................Picture/Brightness Minimum

3-4. HIGH VOLTAGE (HV) CHECK

Standard:............................................................................30.5 ± 0.5 kV
Standard:............................................................................31.5 ± 0.5 kV
Measurement point:............................................................Anode of CRT
Input Video Signal:............................................................All Black Signal
Picture level:..................................................Picture/Brightness Minimum
KV-27HS420/29DRC420/30HS420/32HS420/34HS420/36HS420

SECTION 3: SAFETY RELATED ADJUSTMENTS

(KV-27HS420/29DRC420/30HS420 only)
(KV-32HS420/34HS420/36HS420 only)
KV-27HS420/29DRC420/30HS420/32HS420/34HS420/36HS420
3-5. PREPARATION FOR HV AND IK
PROTECTOR CHECK
1. Remove DZ board screws and carefully lift board as necessary to
gain access to the bottom of the board.
2. Unsolder CN5001 pin 1 to open ABL connection to AY or AZ board.
(Alternately, open AY or AZ - DZ connector (CN509-CN5001) and
carefully push pin 1 metal tab (ABL) up from the bottom and pull up
from the top using long nose pliers and release it from the connector,
then close the connector with pin 1 connection now open.)
3. Install jumper wire from MY or MZ board connection CN2304 pin 1
to CN509 pin 1 to inject 5V to ABL line. (Alternately, use STBY 5V,
IC501 Pin O on AY or AZ board)
4. Unsolder CN5009 pin 8 (H-prot).
5. Open ABL pin 1 of T8001 (RHT) on DZ board and connect analog
current meter.

3-6. HV PROTECTOR CHECK

3-6-1. CUT OFF CONDITION

Input Video Signal:............................................................All Black Signal
Picture level:..................................................Picture/Brightness Minimum
1. Confi rm ABL current which should be approximately 0.160mA.
2. Short across C8002, C8021, and C8052.
3. Turn off the set and install precision VR1 jig (initially set to 100K) to
IC8005 pin 1 (It's the unmarked IC8005 pin on PWB A side, neither K
nor A.) and GND (C8076 -).
4. Restore power and adjust HV to obtain
34.4 ± 0.15kV (KV-27HS420/29DRC420/30HS420 only)
or
35.2 ± 0.15kV (KV-32HS420/34HS420/36HS420 only)
by precision VR1 jig.
Note: If the picture turns bright red or other color and the set shuts
down, place a 10 M resistor on the CX board between G2 and E2
pins on the socket. Confi rm G2 adjustment before returning set to
production.
5. Remove short from C8002 and confi rm that hold down activates.
6. Short C8002 again and confi rm that HV recovers.
7. Re-adjust HV to obtain
31.5 ± 0.2 kV (KV-27HS420/29DRC420/30HS420 only)
or
32.5 ± 0.2 kV (KV-32HS420/34HS420/36HS420 only)
by precision VR1 jig.
8. Remove short from C8002 and C8021 and C8052.
9. Confi rm that hold down does not activate.
Note: Remove the 10 M resistor , if installed in step D above
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