Sanyo M7790K - ELECTRICAL ADJUSTMENTS; EQUIPMENT REQUIRED; HEAD AZIMUTH ADJUSTMENT; TAPE SPEED ADJUSTMENT

ELECTRICAL ADJUSTMENTS
EQUIPMENT REQUIRED
VTVM (2 sets)
Frequency Counter
Dummy Load (47kQ)
Audio Signal Generator
Attenuator
Dualtrace Synchroscope
DC Constant-voltage Regulator
Test Tapes
* 3kHz Test Tape (Example: TEAC MTT-111) for Tape
Speed Adjustment
* 10kHz Test Tape (Example: TEAC MTT-114) for Head
Azimuth Adjustment
* 4QOHz Test Tape for Dolby Calibration Level (Example:
TEAC MTT-150) for Playback Sensitivity Adjustment
e Test Tapes for Recording and Playback Operations
* Chromium Dioxide Tape (Example: TDK AC-51 2)
* Metal Tape (Example: TDK AC-711)
e Alignment Tool
Uniess especially specified, set the unit and
measuring instruments as follows:
@ Function Switch ............... ccc cece cece cece een eeeeneneeees LINE
@ Dolby NR Switch ........... 0. ccc c cece cece cece cece eeeeeeeeeeee OFF
e@ Tape Select Switch .............cc ccc cec cece ec enee ee ees NORMAL
@ Beat Cancel SWitch .............cc cece cece ee eeeeeeeeeseeeeeeees 2
@ Volume Control ............cccceceeeeseaceseeeaeeees Minimum (0)
e Audio Signal Generator output................. 1kHz, OdB (1V)
NOTE:
*
The Electrical Adjustment should be performed in the
order as described below.
Supply 12V DC from the constant-voltage regulator to the
Ext. Power Jack.
TAPE SPEED ADJUSTMENT
1. Remove the Radio Chassis from the unit and connect a
frequency counter to the left or right channel LINE OUT as
illustrated. Then, insert a 3kHz test tape (Example: TEAC
MTT-111) into the cassette compartment.
Frequency Counter
Dummy Load 47kQ. LINE OUT
2. Adjust the tape speed by slowly turning the potentiometer
inside the Motor until the frequency counter reads 3,000Hz
(+30Hz).
Potentiometer for Tape Speed Adjustment
HEAD AZIMUTH ADJUSTMENT
1.
Connect a dualtrace synchroscope and a VTVM to both
channel LINE OUT as illustrated.
Then, set the dualtrace synchroscope as follows:
a! | © D | <a ene CHOP (chopped)
* SOURGE. 2.2.25 5ccc.cciacsctcswes INT (internal), CH1 or CH2
* SWEEP MODE................. suai deacce AUTO (automatic)
NOTE:
Adjust the field on the synchroscope with the VOLT. ADJ.
and TIME ADJ.