(No.YD075)1-13
Fig.4-2c
4.2.3 Height and tilt of the A/C head
Note:
•
Set a temporary level of the height of the A/C head in ad-
vance to make the adjustment easier after the A/C head
has been replaced. (Refer to the SERVICE MANUAL
No.86700 [MECHANISM ASSEMBLY].)
(1) Play back the alignment tape (A).
(2) Apply the external trigger signal to D.FF (E), to observe the
AUDIO OUT waveform and Control pulse waveform at the
measuring points (D1) and (D2) in the ALT mode.
(3) Set the VCR to the manual tracking mode.
(4) Adjust the AUDIO OUT waveform and Control pulse wave-
form by turning the screws (1), (2) and (3) little by little until
both waveforms reach maximum. The screw (1)
and (3) are for adjustment of tilt and the screw (2) for azi-
muth.
Fig.4-2d
4.2.4 A/C head phase (X-value)
(1) Play back the alignment tape (A1).
(2) Apply the external trigger signal to D.FF (E), to observe the
V.PB FM waveform at the measuring point (D).
(3) Set the VCR to the manual tracking mode.
(4) Loosen the screws (4) and (5), then set the Roller driver to
the innermost projected part of the A/C head. (See Fig. 4-
2e.)
(5) Rotate the roller driver so that the A/C head comes closest
to the capstan. From there, move the A/C head back grad-
ually toward the drum until the point where the FM wave-
form is maximized for the second time, and then
tighten the screws (4) and (5) temporarily.
(6) Play an alignment tape (A2) and set to the manual-tracking
mode.
(7) Fine-adjust A/C head base position to maximize the FM
waveform, and then tighten the screws (4) and (5) firmly.
(8) Play alignment tapes (A1) and (A2) and confirm that the FM
waveforms are maximized when the tracking is at the cen-
ter position.
Fig.4-2e
Fig.4-2f
Signal
(A)
• Alignment tape(SP, stairstep, PAL) [MHPE]
Mode
(B)
• PB
Equipment
(C) • Oscilloscope
Measuring point (D1)
(D2)
• TP106 (PB. FM)
• TP4001 (CTL. P)
External trigger (E)
• TP111 (D.FF)
Adjustment part (F)
• A/C head [Mechanism assembly]
Specified value (G) • Maximum waveform
Improper waveform variation
A
B
C
D
Up
Down
Guide roller
(supply side)
Roller driver
Proper waveform variation
Head base
A/C head
AUDIO OUT
CTL. P
(1)
(2)
(3)
Signal
(A1)
(A2)
• Alignment tape(SP, stairstep, PAL) [MHPE]
• Alignment tape(LP, stairstep, PAL) [MHPE-L]
Mode
(B)
• PB
Equipment
(C) • Oscilloscope
Measuring point (D) • TP106 (PB. FM)
External trigger (E)
• TP111 (D.FF)
Adjustment part (F)
• A/C head base [Mechanism assembly]
Specified value (G) • Flat V.PB FM waveform
Adjustment tool (H) • Roller driver [PTU94002]
Head base
Roller driver
To the capstan
To the drum
Toward the capstan
Toward the drum
Screw (5)
Screw (4)
A/C head
Alignment tape
[SP, stairstep]
played with the
SP head
Alignment tape
[EP(LP), stairstep]
played with the
EP(LP) head
Drum side
Control head position
Capstan side
X-value adjustment point
Maximum
Waveform output
