JVC UX-A4 - Mechanism & Amplifier Sections

@ Mechanism & Amplifier Sections
Head azimuth
adjustment
Tape speed
adjustment
Wow and flutter
check
Piayback output
level adjustment
Frequency
response check
°VTT704(12.5kHz)
Test point
‘Headphones
Test tape
: ¥TT712(3kHz)
Test point
: Headphone
Test tape
VTT?712(3kKHz)
Test point
‘Headphone
Test tape
iVTT724(1kHz)
Test point
: DOLBY TP
Test tape
‘VTT — 7063(1kHz)
Test point
: DOLBY TP(
CNAOS)
@ Playback the test tape VTT704(12.5kHz) in the
forward direction, adjust the head azimuth screw
(A) to maximize the headphones output while
minimum the phase difference between channels
@) Playback the test tape in the reverse direction,
adjust the head azimuth screw (B) for the same
purpose as the forward playback,
@ Deviation foward and reverse : within 3 dB
% Whenever the head is changed the azimuth should be
readjusted,
Playback the test tape VTT712 (3kHz) at the tape
end posiition. Shoutd the following tape speed is out
of specification, it is necessary to adjust the VR801
so that standard value obtain within 3000~3020 Hz.
Playback the test tape VTT712(3kHz) to tape start,
midie and end position. Wow and fiutter snould be
within the following allowance at the three positions.
1. Playback the test tape VTT724(1kHz) and switch
the tape select to NORMAL position.
2. Adjust VRA11(LeH) and VRA21{ReH) so that
standard value obtain iess than — 11dB + 1 dB.
3. L, R difference level to be less than + 2dB.
@ Switch tape select to Normal position and
playback the test tape VTT ~ 7063(1KHz).
( Cenfirm the output level at the DOLBY TP
becomes as follaws with reference to 1kKHz.
@ Compare the level between 4 kHz and 63Hz., 1
kHz and 12.5kRz.
@ Then defference level should be within OdB + 4
dB, OdB = 4dB.
UX-A4 B/E/G/GIVEN
Output: within] Head
— 2dB from azimuth
the peak screw
Phase
difference
minimum
Normal speed | VR801
> within
3000~3020HZ
Playback
FWD / REV
should be less
than 0.2% (JIS
RMS)
Less than
-—11dB +1dB] : VRA11
Less than
+ 2dB
63 Hz/ t KHz
ievel
: within O +
4dB
1kHz /
12.5kHz
: within O +
4qB
(No. 1890) 41