3-4
3.4 Audio circuit
Notes:
• This adjustment should be done after the “REC color
(colour) level adjustment” for the video circuit has
been completed.
• GND (Ground) should be taken from the Tuner shield
case.
Signal
(A1)
•
Ext. input
(A2)
•
Audio: No signal
(A3)
•
Video: Color (colour) bar signal [PAL]
Mode
(B)
•
S-VHS LP
Equipment
(C)
•
Oscilloscope
Measuring point
(D)
•
TP2253 (A. PB. FM)
External trigger
(E)
•
TP111 (D.FF)
EVR mode
(F1)
•
Jig code “57”
EVR address
(F2)
•
A : 30
(F3)
•
Jig code “23” and “20”
(F4)
•
Jig code “18” or “19” (C/-)
Specified value
(G1)
•
400 ± 100 mVp-p
(G2)
•
More than 250 mVp-p
Adjustment tool
(H)
•
Jig RCU [PTU94023B]
(1) Apply the external trigger signal to D.FF (E) to observe
the Audio PB FM waveform at the measuring point (D).
(2) Record the signal (A3) with no audio signal input in the
mode (B), and play back the recorded signal.
(3) Set the VCR to the manual tracking mode.
3.4.1 Audio REC FM
3.3.5 Auto picture initial setting
Signal
(A1)
•
Ext. input
(A2)
•
Video: Optional
(A3)
•
VHS tape
Mode
(B)
•
EE
¥
Auto adjust (SP/LP REC
¥
PB)
Adjustment part
(F)
•
Jig code “58”
Specified value
(G)
•
STOP mode
Adjustment tool
(H)
•
Jig RCU [PTU94023B]
(1) Insert the cassette tape (A3).
(2) Set the VCR to the Auto adjust mode by transmitting the
code (F) from the Jig RCU. When the VCR enters the
stop mode, the adjustment is completed. When the VCR
enters the eject mode, repeat steps (1) to (2) again.
(7) Release the EVR mode of the VCR by transmitting the
code (F1) from the Jig RCU again. (When the EVR mode
is released, the adjusted data is memorized.)
(8) Repeat steps (2) to (7) in the mode (B2).
100 kHz
Four scale
1 MHz 2 MHz
Frequency
marker (D2)
Specified
value (G)
5 MHz
V. rate
Scale 4
(4 div.)
Fig. 3-3-4a Video EQ (Frequency Response)
(4) If the A.PB FM level is not within the specified value (G1),
perform the adjustment in a following procedure.
(5) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(6) Set the EVR address to (F2) by transmitting the code (F3)
from the Jig RCU.
(7) Transmit the code (F4) from the Jig RCU to adjust so that
the A.PB FM level of the higher channel level becomes
the specified value (G1). (Adjust before recording, then
confirm it by playing back.)
(8) If the specified value (G1) is not obtained, transmit the
code (F4) from the Jig RCU to adjust so that the wave-
form level of the lower channel level becomes the speci-
fied value (G2). (Adjust before recording, then confirm it
by playing back.)
(9) Release the EVR mode of the VCR by transmitting the
code (F1) from the Jig RCU again. (When the EVR mode
is released, the adjusted data is memorized.)
Fig. 3-4-1a Audio REC FM
V. rate
Specified
value (G1)
Specified
value (G2)
3.5 Syscon circuit
Note:
•
When perform this adjustment, remove the Mechanism
assembly.
3.5.1 Timer clock
Signal
(A)
•
No signal
Mode
(B)
•
EE
Equipment
(C)
•
Frequency counter
Measuring point (D1)
•
IC3001 pin 61
Short point
(D2)
•
IC3001 pin 24
(D3)
•
C3026 + and –
Adjustment part
(F)
•
C3025 (TIMER CLOCK)
Specified value
(G)
•
1024.020 ± 0.02 Hz
(976.5434 ± 0.0191 µsec)
(1) Connect the frequency counter to the measuring point
(D1).
(2) Connect the short wire between the short point (D2) and
Vcc (5V).
(3) Short the leads of capacitor (D3) once in order to reset
the microprocessor of the SYSCON.
(4) Disconnect the short wire between the short point (D2)
and Vcc then connect it again.
(5) Adjust the Adjustment part (F) so that the output fre-
quency becomes the specified value (G).
