Sherwood RX-772, Service Manual

Page: 14 / 32

Ref No.
AMP Sound Dead. A) Signal Mute TR's inferior. Q 352( L, R), Q318(L, R)
1. "LEFT" Channel dead. B) Connector disconnection & disjunction. CP101, CN102
2. "RIGHT" Channel dead. Change or close insertion of the connector.
C) Speaker wire's disjunction.
Close insertion of the speaker wire.
D) Signal switching IC check. I.C No. ( 101 )
1. I.C voltage check ( +12 )V, ( -12 )V I.C Pin No. ( 28, 1 )
2. Switching I.C control data, clk check. I.C Pin No. ( 15, 14 )
3. Switching I.C signal IN/OUT check.
Digi-Link Failure. A) Digi-link line disconnection check.
Digi-Link IN/OUT circuit check. R ( 262, 242 ), D ( 201 )
B) Micom Interface Port Check.
1.
μ
-COM I.C B+(5 )V check.
2 . Digi-link data I/O data check. I.C NO. (201 ) / I.C Pin No. ( 38 )
Remote Controller Failure. A) Battery check.
B) RMC I.C & Resonator inferior.
1.
μ
-COM I.C B+( 5 )V check.
I.C Pin No. ( 15, 16 )
2. REMOCON data check. I.C NO. (201 ) / I.C Pin No. ( 62)
FM Failure. A) FM MUTE adjustment inferior.
B) PLL Line check.
1. PLL control data check. (Data/CE/Clock) IC201 Pin No. (26, 23, 25)
C) TUNER B+ voltage inferior. R205
D)
μ
-COM I.C & Resonator inferior.
I.C No. ( 201 )
1.
μ
-COM I.C B+( 5 )V check.
I.C Pin No. ( 15, 16 )
AM Failure. A) AM V.T voltage inferior.
B) PLL Line check.
1. PLL control data check (Data/CE/Clock) IC201 Pin No. (26, 23, 25)
C) TUNER B+ voltage inferior. R205
D)
μ
-COM I.C & Resonator inferior. I.C No. ( 201 )
1.
μ
-COM I.C B+( 5 )V check. I.C Pin No. ( 15, 16 )
Stereo Effect Failure. A) FM TUNED Inferior. R278, IC201 Pin No(34)
Stereo does not light up. B)
μ
-COM I.C & Resonator inferior. I.C No. ( 201 )
1.
μ
-COM IC B+( 5 )V check I.C Pin No. ( 15,16 )
C) STEREO adjustment inferior. R280, IC201 Pin No(35)
D) FM MUTE adjustment inferior. I.C201 PIN No.(27)
E)
μ
-COM I.C & Resonator inferior.
I.C No. ( 201 )
1.
μ
-COM IC B+( 5 )V check
I.C Pin No. ( 15,16 )
Tuner Sound Dead. A) MUTE TR inferior. Q204
1. "L / R" Channel dead. B) Connector's disconnection or disjunction.
2. "LEFT" Channel dead. Change or Close insertion of the connector.
3. "RIGHT" Channel dead.
Symptom Cause and Remedy