Sherwood R-772 Service Manual page 24

Symptom
OSD Failure.
Video Output Dead.
Video down output Dead.
Video up output Dead.
Digi-Link Failure.
Remote Controller Failure.
Cause and Remedy
3)I2C Control Check.
4)DDC Check.
5)Hot Plug detect Check.
A) I.C voltage check.
1. OSD I.C : ( 5 ) V
2. SYNC Separate I.C ( 5 ) V
B) OSD I.C OSC : ( 14.32 )MHz
C) Micom control data check.
1. DATA/CLOCK/CE
A) Video voltage check.
1. DC voltage check. B+ ( 5 )V, B- ( -5)V
B) Video selector control IC check.
1. DC voltage check. B+( 12 )
2. Micom control data check.
C) Video input detect port check.
1. Micom CV, SV, COMPONENT-V detect port.
A) Video voltage check.
1. DC voltage check. B+ ( 5 )V, B- ( -5)V
B) S-Video input signal check.
1. Yin, Cin signal check.
A) Micom Interface Port Check.
1. SCL, SDA port check.
B) C-Video Input video input signal check.
S-Video Input video input signal check.
C) Component video output check.
A) Digi-link line disconnection check.
Digi-Link IN/OUT circuit check.
B) Micom Interface Port Check.
1. µ-COM I.C B+( 3.3 )V check.
2 . Digi-link data I/O data check.
A) Battery check.
B) RMC I.C & Resonator inferior.
1. µ-COM I.C B+( 3.3 )V check.
2. REMOCON data check.
23
Ref No.
IC No.(1018)
IC Pin No.(26,27)
IC No.(1009)
IC Pin No.(48,49)
IC No.(1018)
IC Pin No.(28,29,33,34)
JACK No.1001,1002,1003
Pin No.19
I.C No. ( 106 )
I.C Pin No ( 12,16,24)
I.C No. ( 108 ) / Pin No. ( 3 )
X-TAL ( 101 )
I.C No. ( 106 )
I.C Pin No. ( 9,10,11 )
I.C No. ( 101,102,103 )
I.C Pin No. ( 7 )
I.C Pin No. ( 16, 17, 18, 19 )
I.C NO. ( 501 ) / I.C Pin No. ( 26,25,24)
I.C NO. ( 109 ) / I.C Pin No. ( 42 )
I.C Pin No. ( 6,29)
I.C NO. ( 504 ) / I.C Pin No. (33,34 )
I.C NO. ( 501) / I.C Pin No. (1,5,2,4)
I.C NO. (502) / I.C Pin No. ( 1,12/5,14/2,15 )
I.C NO.(503) / I.C Pin No.(20,22,24)
IC803 Pin no 1
I.C NO. (402) / I.C Pin No. (7 )
I.C NO. (402) / I.C Pin No. ( 7)