Sharp VC-MH75 (serv.man9) Service Manual ▷ View online
48
VC-MH75HM
YES
YES
NO
NO
FLOW CHART NO.22 Hi-Fi SOUND MODE TROUBLESHOOTING(2)
NO
YES
Replace IC651.
Is there a REC FM signal outputted
at the IC651 pins(29) to (24) (CH-1)
/pins (21) to (22)(CH-2).
at the IC651 pins(29) to (24) (CH-1)
/pins (21) to (22)(CH-2).
Check PC 5V lines.
Check the AGC setting resistor R678
and pin (39) of IC651.
and pin (39) of IC651.
YES
No HI-FI sound recording(E-E mode is posible).
Check peripheral circuit of IC651 as
shown in table.
shown in table.
L-ch pins (16),(17),(18),(19)
R-ch pins (32),(33),(34),(35)
Check AH-MZ harness.
Check or replace the cylinder.
Is the supply voltage of 5V fed to pin
(25) of IC651?
(25) of IC651?
Is there "L" level at pin (36) of IC651?
NO
NO
YES
NO
FLOW CHART NO.23 Hi-Fi SOUND MODE TROUBLESHOOTING(3)
NO
YES
Replace IC651.
Is there playback envelope signal out
putted at pins(29) to (30) of IC651?
putted at pins(29) to (30) of IC651?
Check PC 5V lines.
Is there A-H.SW.P. signal at
pin (27) of IC651?
pin (27) of IC651?
YES
No HI-FI sound playback(E-E mode is possible).
Check peripheral circuit of IC651 as
shown in table.
shown in table.
L-ch pins (16),(17),(18),(19)
R-ch pins (32),(33),(34),(35)
Is the supply voltage of 5V fed to pin
(25) of IC651?
(25) of IC651?
NO
Check the A-H.SW.P. line between pin
(27) of IC651 and pin (28) of IC701.
(27) of IC651 and pin (28) of IC701.
YES
FLOW CHART NO.24 LINEAR SOUND MODE TROUBLESHOOTING(1)
No linear sound recording (E-E mode is possible)
Check the AUDIO MUTE (H) line
between pin (99) of IC201 and pin
(81) of IC701.
between pin (99) of IC201 and pin
(81) of IC701.
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
Is there signal at pin (4) of IC201?
Replace IC201.
Is the supply voltage of 12V fed to
pin (2) of T601?
pin (2) of T601?
Check M 12V line.
Is there signal (Bias) at pin (5) of T601?
Check the Bias oscillation circuit (T601,
Q602,Q603) and A-ERASE CTL line.
Q602,Q603) and A-ERASE CTL line.
Is "L" level applied at pin(99) of
IC201?
IC201?
Check peripheral circuits of T601.
Check the MH-AA harness and A/C
head.
head.
Is there signal (Bias + Audio sig)
at pin (6) of T601?
at pin (6) of T601?
49
VC-MH75HM
YES
YES
NO
Is there signal at pin (100) of IC201?.
Are there MH-AA harness and the PB AMP
peripheral parts normal?
peripheral parts normal?
No linear sound playback (E-E mode is possible)
NO
Is the azimuth height of A/C head properly
adjusted?
adjusted?
Check the AUDIO MUTE (H) line between
pin (99) of IC201 and pin (81) of IC701.
pin (99) of IC201 and pin (81) of IC701.
NO
Is there "L" level at pin (99) of IC201.
Is there signal at pin (11) of IC201.
YES
YES
Replace IC201.
Clean A/C head.
Replace A/C head.
Replace IC201.
Re-adjust azimuth.
NO
YES
YES
YES
YES
PAL EP ONLY
Are there signal at pin(1) of
IC601?
IC601?
YES
NO
Hi-Fi model ONLY
Is there audio signal inputted at
and pin(62) of IC651.
and pin(62) of IC651.
Check line between pin(11) of IC201
and pin(62) of IC651.
and pin(62) of IC651.
FLOW CHART NO.25 LINEAR SOUND MODE TROUBLESHOOTING(2)
50
VC-MH75HM
YES
YES
NO
NO
NO
NO
YES
FLOW CHART NO.26 NICAM/IGR TROUBLESHOOTING
NO
NO
YES
YES
YES
YES
YES
IC1701?
Check peripheral circuit of X1701.
YES
YES
Check peripheral circuit of TU101.
Check between SIF OUT of TU101
and pin(2) of IC1701.
and pin(2) of IC1701.
Check between IIC Data
pins(26),(27) of IC701 and
pins(12),(13) of IC1701.
pins(26),(27) of IC701 and
pins(12),(13) of IC1701.
NO
NO
Is there a base band signal at SIF
OUT of TU101?
OUT of TU101?
Is there a NICAM/IGR audio signal
at pins(31), (30) of IC1701?
at pins(31), (30) of IC1701?
Is there a NICAM/IGR audio signal
at pin(15),(16) of IC2501?
at pin(15),(16) of IC2501?
Is there a base band signal at
pin(2) of IC1701?
pin(2) of IC1701?
Check line between pin(39), (40) of
IC2501 and pins(9), (14) of IC651.
IC2501 and pins(9), (14) of IC651.
See Flow Chart No.21 Hi-Fi SOUND
MODE TROUBLESHOOTING (1)
For Hi-Fi model
MODE TROUBLESHOOTING (1)
For Hi-Fi model
Is 5V supplied at pins(11),(19),(1) of
Check PC 5V line.
Is MPX 8V supplied at pin(33) of IC1701?
Check the REG. circuit of D962.
Check PC Motor 12V line.
Check peripheral circuit of IC1701.
Replace IC1701.
Check serial data and clock at
pin(12) and (13) of IC1701.
pin(12) and (13) of IC1701.
Is there oscillated 18.432MHz at
pins(5), (6) of IC1701?
pins(5), (6) of IC1701?
No NICAM/IGR sound.
51
VC-MH75HM
FLOW CHART NO.27 DECODER TROUBLESHOOTING
SELECT
OUTPUT
INPUT SIGNAL
OUTPUT SIGNAL
<Hi-Fi Audio Double scart>
MODE
SIG.
DECODER CIRCUIT
SIG.
FLOW INPUT
FLOW
(A)
Pin47 of IC701(Y/C video output
E2(L2) video input
Front video input
pin7
pin28
pin25
E1(L1) video output
21PIN CONNECTOR
(B)
(C)
(C)
pin13
pin2
E1(L1) audio output (L-ch)
(A)
(B)
(B)
E2(L2) audio input(L/R-ch)
Pin54 of IC651(Audio output R-ch)
pin33
pin11
pin1 E1(L1) audio output(R-ch)
pin42
21PIN CONNECTOR
(C)
(A)
(B)
(A)
(B)
E2(L2) audio intput(R-ch)
pin34
pin10
pin18 E2(L2) video output(L-ch)
pin43
21PIN CONNECTOR
(C)
(A)
(B)
(A)
(B)
E1(L1) video input
Pin47 of IC701(Y/C video output)
pin23
pin7
pin16
pin26
21PIN CONNECTOR
(C)
(A)
(B)
(A)
(B)
E1(L1) audio input(L-ch)
pin36
pin2
pin15
pin30
(C)
(A)
(A)
(B)
pin37
(
C)
pin1
(A) E2(L2) video input
pin28
(B) E1(L1) video input
pin23
(C) Tuner video output
pin18
(D)
pin13
(A) E2(L2) audio input(L-ch)
pin33
(B) E1(L1) audio input(L-ch)
pin36
(C) MPX output(L-ch)
pin16
(D)
pin11
(A) E2(L2) audio input (R-ch)
pin34
(B) E1(L1) audio input (R-ch)
pin37
(C)
pin15
(D)
pin10
NO
NO
NO
YES
YES
YES
Check STBY 5V line.
Check STBY 12V line.
Check line between pins(21), (22)
of IC2501 and pins(17), (18) of
IC701.
Is there SDA and SCL signal
applied to pins(21) and (22) of
IC2501?
Is voltage 5V applied to the video
section power terminal at pins(24),
(29) of IC2501?
Is voltage 12V applied to the
audio section power terminal at
pins(14) of IC2501?
Check signal line from video and
audio function logic table as shown
below.
Not output from 21pin connector in video and audio signal.
Pin57 of IC651(Audio output L-ch)
Tuner video output
MPX output(L-ch)
Pin57 of IC651(Audio output(L-ch))
21PIN CONNECTOR
E2(L2) audio output (L-ch)
pin31
E2(L2) audio output (R-ch)
21PIN CONNECTOR
Pin31 of IC201
Y/C video input
(Aux. input)
Pin61 of IC651
(Aux. input
Pin52 of IC651
(Audio input (R-ch)
pin5
pin39
pin40
Front audio L-ch input
Front audio R-ch input
Front audio L-ch input
Front audio R-ch input
MPX output (R-ch)
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MPX output(R-ch)
Front video input
(switch)
E1(L1) audio input(R-ch)
Pin54 of IC651(Audio output R-ch)
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