Technics RS-CH770 - Measurements and Adjustments; Power Supply and Signal Checks

RS-CH770
M@ Measurements and Adjustments
This unit RS-CH770 is designed to operate on power supplied from the Amplifier (SE-CH570 or SE-CH770)
through Tuner/Sound Processor (ST-CH570 or ST-CH770).
When connecting the unit to other system components, do not connect to the Amplifier (SE-CH570 or SE-CH770)
directly. Be sure to connect this unit through the Tuner/Sound Processor (ST-CH570 or ST-CH770).
When operating the unit RS-CH770 alone for testing and servicing, without having power supplied from the
Amplifier (SE-CH570 or SE-CH770) and the Tuner/Sound Processor (ST-CH570 or ST-CH770), use the following
method.
®@ To Supply Power Source
Apply 11 V AC power to test points between BUEMS¢g and Bilase74 (GND), and Bulsek# and Buldsievd (GND).
Notes: When operated alone, this unit automatically enter the TEST mode, causing either the DECK1 or DECK2 indicators to
blink.
In TEST mode, please make sure whether the Dolby B indication is on or off by the illumination of DECK 1 cassette
holder is lighted on or off. (DECK 1 illumination is lighted on: Dolby ON, illumination is lighted off: Dolby OFF)
® To Check Signals
Connect an TaN or a built-in amplifier soeaker between line output for L-ch ( Eiiteryd ) and|A.GND}, and line out for R-ch
(Meds ) and| A.GND | and check if the signals are outputting from this unit.
(Power P.C.B.) (Main P.C.B.)
LINE
IN
(R-ch)
TAPE
SPEED
TAPESPEED
PLAYBACK
GAIN
PLAYBACK
GAIN
TP606
DECK
1
(DECK
2:
High)
(DECK
1:
R-ch)
(DECK
2:
R-ch)
A.GND VR801 VR802 VR103
LINE IN (L-ch)
7 PLAYBACK GAIN
DECK
2
VR104
(DECK
2:
L-ch)
LvR803
|
VR102
LINE_OUT (R-ch)
TP608
TP601 cen ae
fied
GND)
—+-+e—
LINE
QUT
(L-ch)
Fig. 2
~~ Unsoldered side
Soldered side
Note:
The above symbol indicates a jumper soldered
on one side. When this jumper is levered up
using a © screwdriver, its unsoldered side is
raised so that it can be seized with an alligator
Clip.
Fig. 1
Measurement Condition Test tape
® Dolby NR switch; OFF ® Head azimuth adjustment (8 kH, -20 dB); QZZCFM
@
Make
sure
heads
are
clean.
©
Tape
speed
adjustment
(3
kHz,
-10
dB);
QZZCWAT
®
Make
sure
capstan
and
pressure
roller
are
clean.
®
Playback
gain
adjustment
(315
Hz,
0
dB);
QZZCFM
©
Judgeable
room
temperature
205°C
(68+9°F)
®
Recording/playback
frequency
response
adjustment;
QZZCFM (315 Hz/0 dB, 315 Hz/-20 dB, 12.5 kHz~ 63 Hz/-20 dB)
Measuring instrument QZZCRA (Norma! blank Tape)
EVM (Electronic Voltmeter) QZZCRX (CrO2 blank Tape)
@ AF oscillator QZZCRZ (Metal blank Tape)
® Digital frequency counter
S15
E
§
5;
3
F
i El Ne