JVC HR-V610EX Service Manual page 12

Proper waveform variation
Improper waveform variation
Up
A
C
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].)
Signal (A) • Alignment tape(SP, stairstep, PAL) [MHPE]
Mode (B) • PB
Equipment (C) • Oscilloscope
Measuring point (D1) • TP106 (PB. FM)
(D2) • TP4001 (CTL. P)
External trigger (E) • TP111 (D. FF)
Adjustment part (F) • A/C head [Mechanism assembly]
Specified value (G) • Maximum waveform
(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.
Head base
(2)
(1)
A/C head
(3)
Fig.4-2d
1-12 (No.YD010)
Down
B
Roller driver
Guide roller
D
(supply side)
AUDIO OUT
CTL. P
4.2.4 A/C head phase (X-value)
Signal (A1) • Alignment tape(SP, stairstep, PAL) [MHPE]
(A2) • 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]
(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.
To the drum
Toward the capstan
Toward the drum
A/C head
Screw (5)
Fig.4-2e
Alignment tape
[SP, stairstep]
played with the
SP head
X-value adjustment point
Drum side Control head position
Roller driver
Screw (4)
Head base
To the capstan
Alignment tape
[EP(LP), stairstep]
played with the
EP(LP) head
Capstan side
Maximum
Fig.4-2f