Technics RS-615US-D - Parts Location

Overall S/N ratio
Equipment:
*VTVM
* AF oscillator
* ATT
* Oscilloscope
* Test tape---C-RA
(reference blank tape)
MEASUREMENT & ADJUSTMENT
. Test equipment connection is shown in fig. 27.
.
Supply
1kHz
signal
to
LINE
IN
and
adjust
ATT
so
that
output
level
at LINE OUT indicates 0.42 V (—74dB).
. Make recording.
_
Make
another
recording
without
supplying
signal
(disconnect
input
plug
to LINE IN).
. Rewind to recorded part and playback.
_
Measure
output
signal
level
and
no
signal
level
(noise),
and
determine
the ratio in decibels (dB).
_
The
value
is
difference
between
“Playback
S/N
and
overall
S/N’,
but
for
decibel
calculation
refer
to
“Playback
S/N
measurement”
on
page
12.
Standard value: Greater than 42dB
(without NAB filter)
REMARKS
* Record/playback mode
* LINE IN level control
++ MAX
* Erase the tape with a bulk
tape eraser.
Level meter
Equipment:
*VTVM
* Oscilloscope
* AF oscillator
. Supply 1kHz signal (—24dB) from AF oscillator, through ATT, to
LINE IN jack.
. Place UNIT into record mode.
. Adjust ATT until monitor level at LINE OUT becomes 0.42 V.
_ Adjust VR9 (L-CH), VR10 (R-CH) so that VU meter indicates 0 VU
(See adjustment parts location on page 18).
ian
* Record mode
Dolby NR circuit
Equipment:
+ VTVM
* AF oscillator
* ATT
* Oscilloscope
. Place UNIT into record mode, set the Dolby NR switch to OUT posi-
tion and supply to LINE IN to obtain —34.5dB at TP3 (L-CH), TP4
(R-CH) (frequency 5kHz).
_ Confirm that the value at IN position is 8dB greater than the value at
OUT position of Dolby NR switch.
_ When it is not in condition above, adjust as follows.
. Set VR5 (L-CH), VR6 (R-CH) to maximum.
. Set the Dolby NR switch to IN position.
_
At
this
time
adjust
VR7
(L-CH),
VR8
(R-CH)
so
that
the
reading
of
VTVM become 10dB greater than the value in step (1) above.
. Adjusting VR5 (L-CH), VR6 (R-CH), make the reading of VTVM be-
come 2dB smaller than the value obtainted through the adjustment a
in step (6) above.
* Record mode
* LINE IN level control
wes MAX
* Stop the bias oscillation
by unsoldering point (A)
shown in adjustment parts
location on page 11.
ADJUSTMENT PARTS LOCATION
Tape speed
adjustment VR
VR5 VR7Z VR9 VR1O
L6 LS
Fig. 36
* Dolby is the trade mark of Dolby Laboratories Inc.
VR2
18