JVC GR-SXM277UA Service Manual page 35

4.3 MECHANISM COMPATIBILITY ADJUSTMENT
4.3.1 Tape transport adjustment
Mechanism adjustment is needed when DRUM ASSEMBLY or a
part of the tape transport system is replaced. To protect tapes
from damage, first clean the tape transport system, next confirm
that nothing is wrong with the tape transport system by using a
tape that can be disposed of, and then perform adjustment with
alignment tape. Some exterior parts should be removed before
some adjustment procedures, depending on the procedures.
POLE BASE (SUP)
(GUIDE ROLLER)
TENSION
POLE
Fig.4-3-1
4.3.2 Back tension
Remove the exterior parts attached to CASSETTE HOUSING
ASSEMBLY so that scales of CASSETTE TORQUE METER can
be read.
• CASE COVER(S),(M) ASSEMBLY
• C. COVER INSIDE
CASSETTE TORQUE METER
Fig.4-3-2
(1) Set a cassette torque meter onto the deck and measure the
back tension in standard PB mode to confirm that the back
-3
tension is 0.97x10 - 1.71x10
(2) If not, replace the tension band.
When the value widely fluctuates in the measurement,
replace the SUPPLY REEL DISK.
(3) With the CASSETTE TORQUE METER, confirm that the
-3
play torque is 1.47x10
If necessary, replace the center pulley unit.
POLE BASE (TU)
(GUIDE ROLLER)
TU GUIDE
POLE
A/C HEAD
ASSEMBLY
PINCH
ROLLER
-3
N•m.
-3
- 2.45x10 N•m.
BACK TENSION
-3 -3
0.97x10 - 1.71x10 N
(10-17gf·cm)
Fig.4-3-3
4.3.3 Tape pattern
Remove the exterior parts attached to the UPPER CASE
ASSEMBLY so that the guide roller beside the DRUM ASSEMBLY
can be rotated.
• LOWER CASE ASSEMBLY
• TOP OPE UNIT
• CASE COVER(S),(M) ASSEMBLY
• UPPER CASE (S),(M) ASSEMBLY
NOTE:
In performing adjustment, it is recommended that LOWER
CASE ASSEMBLY and TOP OPE UNIT are attached to the
main body for better operation and safety.
POLE BASE (TU)
(GUIDE ROLLER)
POLE BASE (SUP)
(GUIDE ROLLER)
Fig.4-3-4
(1) Remove the Cover (JIG) shown on Fig.4-2-1.
(2) Connect the JIG CONNECTOR CABLE to CN25 on the
MAIN BOARD ASSEMBLY as shown on Fig. 4-2-2.
(3) Observe signal at V_TP_FM with external trigger from
V_FF on the JIG CONNECTOR CABLE.
(4) Playback the SP stairstep signal of the alignment tape and
maximize the FM waveform by the tracking button.
(5) Set the tracking control to the center position by simulta-
neously pressing the tracking (-) and (+) buttons and max-
imize the FM waveform by the tracking button.
(6) If the observed FM waveform is not flat, adjust the height of
the SUPPLY of TAKE-UP GUIDE ROLLER with the roller
driver.
NOTE:
To prevent the tape from damage, turn the guide rollers
slowly.
m
•
PLAY TORQUE
-3 -3
1.47x10 - 2.45x10 N·m
(15-25gf·cm)
ALIGNMENT TAPE
JIG CONNECTOR CABLE
MAIN CN25 - JIG BOARD
12PIN(V_TP_FM)
13PIN(V_FF)
(No.YF016)1-17