![background image](http://html1.mh-extra.com/html/viewsonic/a90f-1/a90f-1_service-manual_1020116005.webp)
1.8
Voltage Breakdown Test
Connent the live pin and neutral pin together. Switch the monitor on/off switch to on. Apply 1500VAC
RMS or 2250VDC, 50Hz for one minute between this connection point(live and neutral pin short) and
earth. Ensure no voltage breakdown occurs.
1.9
Earth Resistance/Continuity Test
Measure the resistance between the signal cable metal shell and the earth pin in the A.C. socket. At a
current of 25 amperes, the resistance should be less than 500mohm.
NOTE:
A portable appliance tester (PAT) is a suitable instrument to use for the above safety tests.
1.10
H.V. Over Voltage P
rotection
(Required for X-Radiation Safety)
Adjust R176 slowly anti-clockwise until the over voltage protection circuit is activated, and the high
voltage must be less than 33KV just before the activation. After test, R176 should be adjusted back to
normal(=25.9KV)
CAPACITOR:
C850 400V 4700PFM
CAPACITOR.CERAMIC
5230105501
C851 400V 4700PFM
CAPACITOR.CERAMIC
5230105501
C135 250V 33UFM
CAPACITOR.ELECTROLYTIC 5214433012
C139 100V 330UFM
CAPACITOR.ELECTROLYTIC 5214019612
RESISTOR
R827 1/4w 2K
ohm
RESISTOR.VR
5162161220
SEMICONDUCTORS
I803 UC3842N
IC
LINEAR
6644063111
I301
TDA9116 SDTP-32
IC.LINEAR A.S.D.C.
6644076308
I310 TDA8172
7P
IC.LINEAR
6644076000
I101 UC3842N
IC.LINEAR
6644063111
IA01
NT68F62U SDIP-42
IC.LSI MCU
6647008204
Q121
2SK2843
TR FET MOS
6626003202
Q433 BU4525AX
TR
NPN
6621002801
Q801
2SK2648
TR FET MOS.
6626003208
D827 HZ5C1
DIODE
ZENER
6615007834
OTHERS
SR801 CSA-SS-212DM5
RELAY
5054613402
F801 250V/3.15A
FUSE
5054431539
T801 TPW-697
POWER
TRANSFORMER
5061369700
T101 (RA)
TFB-280T
TRAQNS.FLYBACK COLOR
5062628031
T101 (RB)
TFB-280L
TRAQNS.FLYBACK COLOR
5062628032
V901 (RA)
M46QCK761X123 (TCO
MDT)
CCRT/DY 5051286346
ViewSonic Corporation
2
Confidential – Do Not Copy
A
9
0f+-1
Summary of Contents for A90f+ 1
Page 57: ...12 PCB Layout ViewSonic Corporation 54 Confidential Do Not Copy A90f 1...
Page 58: ...VIDEO PWB 0414 ViewSonic Corporation 55 Confidential Do Not Copy A90f 1...
Page 59: ...KEY CONTROL PWB 0488 ViewSonic Corporation 56 Confidential Do Not Copy A90f 1...
Page 60: ...MAIN BOARD 13 Schematic Diagrams ViewSonic Corporation 57 Confidential Do Not Copy A90f 1...
Page 61: ...VIDEO ViewSonic Corporation 58 Confidential Do Not Copy A90f 1...
Page 62: ...KEY CORTROL ViewSonic Corporation 59 Confidential Do Not Copy A90f 1...
Page 63: ...POWER SUPPLY CKT ViewSonic Corporation 60 Confidential Do Not Copy A90f 1...
Page 64: ...MCU CONTROL CKT ViewSonic Corporation 61 Confidential Do Not Copy A90f 1...
Page 65: ...Time Base DeflectionCKT ViewSonic Corporation 62 Confidential Do Not Copy A90f 1...
Page 66: ...H V DYNAMIC FOCUS CKT ViewSonic Corporation 63 Confidential Do Not Copy A90f 1...
Page 67: ...14 Exploded Diagram ViewSonic Corporation 64 Confidential Do Not Copy A90f 1...