Sharp QT-CD121H (serv.man2) Service Manual ▷ View online
QT-CD121H/112H
– 29 –
TROUBLESHOOTING
When the CD does not function
When the CD section does not operate When the objective lens of the optical pickup is dirty,this section may not operate.Clean
the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check
the following items.
Remove the cabinet and follow the troubleshooting instructions.
"Track skipping and/or no TOC(Table Of Contents) may be caused by build up of dust other foreign matter on the laser pickup lens.
Before attempting any adjustment make certain that the lens is clean. If not, clean it as mentioned below."
the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check
the following items.
Remove the cabinet and follow the troubleshooting instructions.
"Track skipping and/or no TOC(Table Of Contents) may be caused by build up of dust other foreign matter on the laser pickup lens.
Before attempting any adjustment make certain that the lens is clean. If not, clean it as mentioned below."
Turn the power off.
Gently clean the lens with a lens cleaning tissue and a small amount of isopropyl alcohol.
Do not touch the lens with the bare hand.
Gently clean the lens with a lens cleaning tissue and a small amount of isopropyl alcohol.
Do not touch the lens with the bare hand.
See if the pick-up is in the pick-up in SW702 position.
If the items mentioned above are OK, check the main
microcomputer IC701.
microcomputer IC701.
Yes
Yes
• The CD function will not work.
The CD operating keys don't work.
Check the CD, DPS microcomputer (IC701), power supply, 4.19
MHz and 16.93 MHz clock, and reset terminal.
MHz and 16.93 MHz clock, and reset terminal.
Check the waveform of SCK, SO (DATA) and SI (COMM).
Yes
Yes
Playback can be performed without a disc.
Yes
Does the output waveform of IC801(16)(FD) match that shown in
Fig. 29?
Fig. 29?
Check the area around IC804-BI801/CNS801.
Yes
Check the IC801(50)(CLK) line, 4MHz.
Check the microcomputer data on pins (51)(CL), (52)(DAT) and
(53)CE.
Check the microcomputer data on pins (51)(CL), (52)(DAT) and
(53)CE.
Figure 29
• The CD operating keys work.
No
Yes
No
Does the pick-up move up and down twice?
Focus search OK.
Focus search
is performed
two times
when play
operation is
done without
disc.
is performed
two times
when play
operation is
done without
disc.
0.5s
0.50 V
IC801 16 FD
0.50 V
IC801 16 FD
2
1
0.5s
0.50 V
IC801 15 TD
0.50 V
IC801 15 TD
Check the Focus - HF system.
QT-CD121H/112H
– 30 –
Check the laser diode driver.
• Playback can only be performed when a disc
is loaded.
Does the DRF signal change from "L" to "H"?
No
If the disc is not turning, the DRF
should not change to "H".
should not change to "H".
Is HF waveform normal (see the Fig. 30-1, 2)?
Yes
Is the Focus servo active? (Can you hear it working?)
No
Check the area around IC801(16) - (21) (focus servo circuit).
L
evel is abnormal.
Check the periphery
of IC801 pins 41 and
42.
of IC801 pins 41 and
42.
No
Waveform is unstable.
Check the spin
system.
system.
Yes
Yes
Yes
Yes
Yes
Figure 30-2
Figure 30-1
Check the spin
system.
system.
HF
0.1V/DIV
0.5µsec/DIV(DC)
(When playing
back the disc)
0.1V/DIV
0.5µsec/DIV(DC)
(When playing
back the disc)
Waveform in case
of normal play-
back
of normal play-
back
3
2
1
1
4
0.5s
1.00 V
IC801 16 FD
1.00 V
IC801 16 FD
0.5s
10.0 V
IC801 12 CLV+
10.0 V
IC801 12 CLV+
0.5s
10.0 V
IC801 54 DRF
10.0 V
IC801 54 DRF
0.5s
2.00 V
IC801 7 TE
2.00 V
IC801 7 TE
Check the tracking system.
▼
▼
▼
• Check the tracking system.
Check waveform of IC801 pin 7 (TE).
Check the periphery of IC801
pin 8 to pin 15, and IC804 to
BI801/CNS801.
pin 8 to pin 15, and IC804 to
BI801/CNS801.
Tracking servo is inoperative.
The waveform shown in Fig. 30-3
appears, and no-disc state appears
soon.
appears, and no-disc state appears
soon.
Yes
Yes
Yes
Yes
Play is possible in
TEST mode.
TEST mode.
Although IL is possible,
play is impossible.
play is impossible.
Normal jump is impeded, and the
program top cannot be reached.
program top cannot be reached.
Check the periphery of
IC801 pin 14.
IC801 pin 14.
Yes
Data cannot be read.
Check the VCO-PLL system.
Yes
3
4
5ms
1.00 V
IC801 7 TE
1.00 V
IC801 7 TE
5 ms
5.0 V
IC801 54 DRF
5.0 V
IC801 54 DRF
Figure 30-3
QT-CD121H/112H
– 31 –
The turntable fails to rotate or rotates at high speed.
Yes
Check the periphery of IC801 pins 23 to 27, pin 39 and pin 40,
IC802 pin 12 and pin 13, IC804 to BI803/CNS803.
IC802 pin 12 and pin 13, IC804 to BI803/CNS803.
The turntable rotates a little.
Yes
The spin driver circuit is normal.
Play operation is performed without disc.
• Checking the spin system.
No
Yes
Check the IC801 pins 43 and 44, IC802 pins 3, 5, 7, 9 and 10.
Error
Yes
Check PDO waveform (Fig. 31).
• Checking the VCO-PLL system
Play operation is performed when disc exits.
Yes
Although HF waveform is normal, TOC data cannot be read.
Figure 31
2
3
0.5s
1.00 V
IC802 3 PDO
1.00 V
IC802 3 PDO
0.5s
1.00 V
IC801 16 FD
1.00 V
IC801 16 FD
As VCO freque-
ncy is locked at
4.32 M Hz,
voltage of PDO
rises and stabili-
zes.
ncy is locked at
4.32 M Hz,
voltage of PDO
rises and stabili-
zes.
Stop --> Play
Check IC802 pins 37and 40.
Check the periphery of IC803 (OPAMP).
Abnomal
Usually, the number of pulses of flawless disc is 100 pulses/sec
or less.
or less.
No
Yes
Check IC802 pin 48 (EFLG).
• Although HF waveform is normal and the time
indication is normal, no sound is emitted.
QT-CD121H/112H
– 32 –
1*
P03
MTCONT2
Input/Output Used to input or output 4 bits at a time. When the output latch is set to "1", the unit will be in the
input mode. The key-on wakeup function, which can be switched on or off by the software, and a
pull-up transistor, which can be turned on or off by the software, are built in.
pull-up transistor, which can be turned on or off by the software, are built in.
2*-5*
P10-P13
POWER-IN,
Input/Output Used to input or output 4 bits at a time. When the output latch is set to "1", the unit will be in the
DATA (VOL),
input CK (VOL), mode.The key-on wakeup function, which can be switched on or off by the software,
STB (VOL)
and a pull-up transistor,which can be turned on or off by the software, are built in.
6*
D0
POWER-ON
Input/Output Each terminal can be used to input or output 1 bit at a time. The output section has a latch which
holds 1 bit. One of the D ports is assigned by register Y as a data point, to execute input or output.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
7
D1
MUTE
Input/Output Each terminal can be used to input or output 1 bit at a time. The output section has a latch which
holds 1 bit. One of the D ports is assigned by register Y as a data point, to execute input or output.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
8*-12
D2-D6
SYNC-OUT,
Input/Output Each terminal can be used to input or output 1 bit at a time. The output section has a latch which
RES,CQCK,
holds 1 bit. One of the D ports is assigned by register Y as a data point, to execute input or output.
COIN,REC
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
be set to "1" using the CLD command.
13,14
D7,D8
SL+,SL-
Input/Output Each terminal can be used to input or output 1 bit at a time. The output section has a latch which
holds 1 bit. One of the D ports is assigned by register Y as a data point, to execute input or output.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
15*,16*
D9,D10
SRS2,SRS1
Input/Output Each terminal can be used to input or output 1 bit at a time. The output section has a latch which
holds 1 bit. One of the D ports is assigned by register Y as a data point, to execute input or output.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
To use the port for input, set the output latch for that bit to "1". All of the output latches on port D can
be set to "1" using the CLD command.
17
P20
DRF
Input/Output Used to receive 4 bits at a time.
18
P21
SQOUT
Input/Output Used to receive 4 bits at a time.
19
P22
WRQ
Input/Output Used to receive 4 bits at a time.
20
P23
PU-IN
Input/Output Used to receive 4 bits at a time.
21
RESET
Input/Output Reset pulse input/output terminal. When a reset is caused by the watch dog timer, an "L" level will
be output. The output is an N channel open drain.
22
XIN
Input
Input/output terminals for the main clock generation circuit. Used by connecting a ceramic resonator
between the XIN and XOUT terminals. There is a built-in feedback resistor between the XIN and
XOUT terminals.
between the XIN and XOUT terminals. There is a built-in feedback resistor between the XIN and
XOUT terminals.
23
XOUT
Output
Input/output terminals for the main clock generation circuit. Used by connecting a ceramic resonator
between the XIN and XOUT terminals. There is a built-in feedback resistor between the XIN and
XOUT terminals.
between the XIN and XOUT terminals. There is a built-in feedback resistor between the XIN and
XOUT terminals.
24
VSS
—
GND input terminal.
25
VDD
—
Positive power supply terminal.
26*
XCOUT
Output
Input/output terminals for the sub clock generation circuit. Used by connecting a crystal oscillator
between the XCIN and XCOUT terminals. There is a built-in feedback resistor between the XCIN
and XCOUT terminals.
between the XCIN and XCOUT terminals. There is a built-in feedback resistor between the XCIN
and XCOUT terminals.
27
XCIN
Input
Input/output terminals for the sub clock generation circuit. Used by connecting a crystal oscillator
between the XCIN and XCOUT terminals. There is a built-in feedback resistor between the XCIN
and XCOUT terminals.
between the XCIN and XCOUT terminals. There is a built-in feedback resistor between the XCIN
and XCOUT terminals.
28
AVSS
Input
GND input terminal for the A-D converter.
29
VREF
Input
Reference voltage input terminal for the A-D converter.
30
P30
REMOCONINT2
Input
Used to receive 4 bits at a time.
31
P31
TORAY1
Input
Used to receive 4 bits at a time.
32
P32
TORAY2
Input
Used to receive 4 bits at a time.
33
P33
Input
Used to receive 4 bits at a time.
34
P40
Input
Used to receive 4 bits at a time.
35-37
AIN5-AIN7
Input
Used to receive 4 bits at a time.
38-40
VLC3-VLC1
Input
LCD power input terminals. To use the internal resistor, connect VLC3 to VDD (if a brightness
control is needed, connect VLC3 to VDD through a resistor). When an external power supply is
used, applyvoltages as follows: 0<VLC1<VLC3<VLCD<VDD.
control is needed, connect VLC3 to VDD through a resistor). When an external power supply is
used, applyvoltages as follows: 0<VLC1<VLC3<VLCD<VDD.
41-44
COM3-COM0
Output
LCD common output terminals.
45-61*
SEG16-SEG0
Output
LCD segment output terminals.
(45*-56*)
62*-64*
P00-P02
Input/Output Used to input or output 4 bits at a time. When the output latch is set to "1", the unit will be in the
input mode. The key-on wakeup function, which can be switched on or off by the software, and a
pull-up transistor, which can be turned on or off by the software, are built in.
pull-up transistor, which can be turned on or off by the software, are built in.
FUNCTION TABLE OF IC
IC701 RH-iX0105AWZZ (IX0105AW): System Control Microcomputer
Port Name
Function
Terminal
Name
Pin No.
Input/
Output
In this unit, the terminal with asterisk mark (*) is (open) terminal which is not connected to the outside.
Click on the first or last page to see other QT-CD121H (serv.man2) service manuals if exist.