JVC GR-AXM17US Service Manual page 21

4.3.5 Phase of control head (X value)
Note:
Remove the exterior parts attached to the UPPER CASE
ASSEMBLY so that the screws around the A/C HEAD
ASSEMBLY can be tighten or loosen.
(1) Connect the JIG CONNECTOR CABLE to CN25 on the
MAIN BOARD ASSEMBLY.
(2) Playback the SP stairstep signal of the alignment tape and
observe signal at V_TP_FM with external trigger from
V_FF on the JIG CONNECTOR CABLE.
(3) Operate the tracking button in the center and manual
tracking mode by pressing the tracking (+) and (-) buttons
and confirm that the FM output level is maximum at
the center position as shown in Fig. 4-3-10.
(4) If necessary, slightly loosen the setscrews [D] and [E] and
insert the Tweezers into the notch and guide hole to move
the A/C HEAD fully in the direction of the capstan to the
extent.
(5) Gradually move the A/C HEAD toward the drum to find the
position where the FM output level maximum for the first
time (A' - B' in Fig. 4-3-10).
(6) Fine adjust the phase of the A/C HEAD and tighten the
screws [D] and [E] at the point A.
A/C HEAD
SCREW [D]
Fig.4-3-9
A
ADJUSTING
POINT
FM OUTPUT
DIRECTION OF CAPSTAN
A/C HEAD PHASE
Fig.4-3-10
INSERT THE
TWEEZERS
SCREW [E]
B
MAX
ZERO
DIRECTION OF DRUM
(No.YF073)1-21