Technics Quartz Direct Drive automatic turntable system SL-L2[M] – troubleshooting, disassembly, mechanical and electrical adjustments
How to remove turntable platter
Open the upper cabinet.
Remove the turntable mat, and lift the turntable platter.
[when removing turntable platter, it is not necessary to remove the 45rpm adopter. The turntable platter is tightly fitted to the center spindle. When removing it, take care not to damage the upper cabinet.}
To remove the dust cover,
Remove the terminal solder by using a solder sucker.
Hold the Hall element with tweezers and remove it while touching the soldering iron to the terminal.
(Fit the hall element with the part number Print “UP”.
How to remove the tonearm.
Remove the dust cover.Remove the shield cover setscrew.
Unsolder the 5 lead wires.
Turn the worm gear with your fingers to remove the tonearm inward.
To remove the offset angle detection circuit board.
Remove the indicator cover setscrew.
Remove the indicator cover.
How to remove the arm dirive motor.
Remove the dust cover.
Remove the two setscrews.
Unsolder the two lead wires from the motor.
Open the cushion rubber.
How th remove the stylus set-down position volume circuit board setscrew.
Remove the cover.
Remove the stylus set-down position volume circuit board setscrew.
How to remove the reset switch.
Remove the screw.
Remove the two claws of the switch holder.
Unsolder the two switch terminals.
[when replacing the reset switch, be sure to open the upper cabinet]
How to set the tonearm drive chord.
Remove the dust cover and tonearm cover.
Remove the roller cover.
Set the chord in the order of steps 1 to 6.
Fit the chord connector to the tonearm.
Set the roller cover and turn the worm gear by hand to see the torn am moves.
How to remove the 45 rpm adapter.
The two adapter claws fit into the turntable platter. Remove the 45rpm adapter by pushing by pausing it in. [when removing the 45rpm adapter, remove the turntable platter; otherwise the adapter claws will be broken.]
How to remove turntable platter.
Open the upper cabinet. Remove the turntable mat, and lift the turntable platter. [when removing the platter, it is not necessary to remove the 45rpm adapter. The turntable platter is tightly fitted to the center spindle. When removing the platter, take care not to damage the upper cabinet.
How to remove the bottom board.
Turn over the unit on a soft cloth.
Remove the six screws.
How to remove the power switch.
Remove the three screws.
Lift the holder slightly.
Pull out the power switch.
How to remove the Hall element.
Remove the terminal solder.
Hold the Hall element with a tweeter and remove it while touching the soldering iron to the terminal.
How to use the repair table.
Remove the bottom board.
Remove the operation circuit board and connect the PCB ground terminal to the chassis (stator frame)
Put the unit on the repair table.
Fit the turntable platter and put the turntable mat.
Put on the record and check the circuit from under the unit.
How to raise the set.
Turntable platter is not fixed on the center spindle. Take care so that the platter will not come loose. Take care allow the set the set to fall down.
Remove the bottom board.
Completely open the upper cabinet.
Hold the reset switch (cabinet) with the tape.
Fit the turntable platter.
Raise the unit and check the circuit.
How to turn over the set.
The purpose is to check the voltage of each circuit point during stop of the turntable.
Remove the turntable platter and turn over the unit.
Remove the bottom board.
Turn the power switch ON and check the voltage.
How to remove the cartridge.
Open the upper cabinet.
Remove the setscrew and pull out the cartridge. [when attaching the cartridge, match the tonearm connector with the cartridge pin, and completely insert it and tighten the setscrew.]
Adjustment points.
Turntable drive control schematic
Troubleshooting Measurements and adjustments
Start position:
Open the upper cabinet and put on the record.
Turn the power switch ON.
Push the Start switch.
Turn the start position adjusting screw. If it descends between tunes, turn it counterclockwise.
Clock frequency:
Connect the lead wire with clip to IC301 29pin of operation circuit board.
Connect the scope to IC301 8pin.
turn the power switch ON.
Adjust VR301 so that the cycle of the output waveform is 1.6msec +/-0.06msec.
Sensor gain:
Connect DC voltmeter to IC401 12pin + and Ground.
Put on the record for adjustment with A side up.
Turn the power switch ON.
Torn arm is on a between songs gap [blank area of the reord]
Adjust VR401 so that the output voltage is 8.5 +/- 0,3v.
Sensor resolution:
Connect the Scope to the IC401 9pin + to ground.
Put on the record for adjustment with slide A up.
Turn the power switch ON.
Keep the ‘F’skip switch depressed to move the tonearm. (output is delivered between tunes is 3.0 +/- 0.3v.
Stylus cue-down position: open the upper cabinet and hold the cabinet switch with tape.
Put on the record for adjustment with side B up.
Close the upper cabinet.
Connect the unit to amplifier (connect the speakers to the speaker terminals)
Turn the power switch ON.
Press the ‘F’ skip switch twice and then press the start switch.
After completion of cueing, again press the ‘B’ skip switch to cue down.
Make sure that the descending position is around 18 – 19.
Tonearm offset angle:
Remove the dust cover. Open the upper cabinet and hold the cabinet switch with tape.
Close the upper cabinet.
Put on the record.
Turn the power switch ON.
Keep the ‘F’ skip switch depressed to move the tonearm.
Turn the adjusting screw so that the arm center matches the V-groove of the lift bar.
Servo gain and offset voltage:
Remove the dust cover.
Open the upper cabinet and hold the cabinet switch with tape.
Connect the DC voltmeter to CN301 5-pin + and Ground.
Remove the sensor cover.
Turn the power switch ON.
Keep the ‘F’ skip switch depressed to move the tonearm.
Open the upper cabinet.
Completely shift the tonearm to the left, and then adjust VR501 so that the voltage is 6.0V[servo gain].
Set the tonearm to the center and make sure that the output voltage is 3.0v.
If the voltage is not 3.0v, adjust the set screw, so that the output voltage is 3.0v [offset voltage].