Technics RS-CH7 - Page 9

ERASE CURRENT CONFIRMATION (DECK 2)
1. Insert the Metal blank test tape (QZZCRZ) and set the unit
to the Record Pause mode.
2. Check if the output at this time between the erase current
confirmation point and (chassis) (the output
on both edges of R302) is within the standard value.
Standard value: 190 mA+5 mA (Metal)
OVERALL FREQUENCY RESPONSE (DECK 2)
. Insert the Normal blank test tape (QZZCRA) and set the
unit to the Record Pause mode.
. Apply a reference input signal (1kHz, —24dB) through an
attenuator,
. Attenuate the signal by 20dB and adjust the frequency
from 50H2~10kHz.
. Record the frequency sweep.
. Playback the recorded signal and assure that it is within
the range shown in Fig. 8 in comparison to the reference
frequency (1kHz).
. If itis not within the standard range, adjust VR302 (L-CH) and
VR303 (R-CH) so that the frequency level is within the
standard range.
@Level up in high frequency range Increase the bias
current.
Decrease the bias
current.
.
Repeat
steps
2~6
above
using
the
CrO,
tape
(QZZCRX)
and
the
Metal
tape
(QZZCRZ)
increasing
the
frequency
range
to
12.5kHz
(50Hz~12.5kHz).
.
Assure
that
the
level
is
within
the
range
shown
in
Fig.
9.
Level down in high frequency range
LINE IN LINE OUT
AF oscillator = ATT EVM Oscilloscope
LINE OUT (Leh):
(Rh): aoe
LINE IN (Lch):
(Reh):
OVERALL GAIN ADJUSTMENT (DECK 2)
. Insert the Normal blank test tape (QZZCRA) and set the
unit to the Record pause mode.
. Apply a_ reference input signal (1kHz, -—19 dB).
Attenuate the output so that its level becomes 0.4V.
. Record this input signal.
. Playback the signal recorded in step 3 above, and assure
that the output is within the standard value.
. If it is not within the standard value, adjust VR7 (L-CH) and
VR8 (R-Ch).
. Repeat the step 2~5 above until the output is within the
standard value.
Standard value: 0.4V+0.5dB
ERASE HEAD EVM
(Electronic
Voltmeter
Normal Overail frequency response chart (NR OUT)
a
LUT
PSE) ae ater
LTT TT TNT OT
a a
eS Pe eee
SOHz 100H2 200Hz rl TkHZ 2kHz
Fig. 8
CrO, Metal Overall frequency response chart (NR OUT)
S5O0Hz 100Hz 200Hz SOOHZ IkHz 2kHz 12.5kHz
Fig. 9
(Lch) (Lch) ETE
(Rh) (Reh)
LINE IN UNE OUT
| Baas OCP
AF oscillator
-11-
RS-CH7 RS-CH7
m@ BLOCK DIAGRAM
AN7384N
ELECTRIC VOLUME
O21~ 23,D5~8
Muting
drive
LINE IN O-
(Len)
CXAI33IM-T6 \
| DOLBY B/C RR |)
i
|
cae
| f |
3
r
|
>
REC jevel @ Cc 4
epniret BA4558F TI
(C7 (1/2) wos |
(18)
13
< i + <
Notes: AN7351SCE2 |
1) ¢ Jindicates Pin No. of (C2 (1/2) |
right channel MS selector
2) REC/PLAYBACK AMP control - L___J
> PLAYBACK SIGNAL | aaaseeeii 0151016)
I>
REC
SIGNAL
!
€8)
1c5
Mee)
Muting
Se ree lo ma ‘drive
—s VR3(VR4)
| Vee cno | (PLAYBACK GAIN ADJ.)
| [3s DECK!
OECKI 48) op
PETERHEAD > 7 34 (PLAYBACK GAIN
(Len) Ko) AAD
wks. | bao ——— TI es oh 4 VRS(VR6)
|
03104) | ‘
|
i
|
[a]
de
DECK2
M50963-2
Switching
ud
1
ti
[rit]
0907
1C90
iplay-on) ~—--44-4--4 7] Ae 0903
io)
fj
i2op
Ua
feed
J
8p
fe
[
Vv
MICRO
CO
OI [0902 PI im) (OVERALL =) 34>:
cpa) B yf aie GAIN ADJ.) L_ she
&: ~~
| pas eg AEN OS pia 26 =
(28) S VR7 (VRE) |
DECK2 23] {
R/P HEAD <> R (314 3 sal
(Leh) ~bMSP P
| Y BA4558F TI
| ‘
L
REC
level
det.
ORLV
|; so73_ |
(ATS/CrO2)
42h
05,7,9, 11,13 <2 2
af (06,8,10,12,14} asl —
> <3 2
Selector
( Normai/METAL/CrO2) of awa
Aosis
VR303
(VR302)
(B14S CURRENT ADJ.)
Bios OSC
control
VR30I
jUCONSUMPTION
| CURRENT
ADJ.)
L301
9301, |302
Bias OSC
DECK2
ERASE HEAD i” o
TP3O!
Oo o-
-12-
- 2h Rez
i 60
| Pe SOTIMODE) 4g NobE’t
faerewer) on} 61 HALE |
0303, 304,904, 0904~907 |
DNBSIALB |
|
HALL IC |
36
SO76A SO75A GD grec
{ATS/METAL) & } {ATS/CrO2)
DECK! 717,719 |
Solenoid NX A Dg7I
Solenoid 624 sou
drive |
(SPEED 7404 )
Wee
fat
|
Saee