AKAI X-165D (01) PDF MANUAL

Recording System: In-Line 4 track stereo/monaural Cross-Field Head recording system.

Playback System: In-Line 4 track stereo/monaural playback system.

Tape Speed: 1-7/8, 3-3/4, 7-1/2 ips (15 ips optional)

Tape Speed Deviation: Within ± 1.5% at all tape speeds.

Wow and Flutter (Playback only):

Less than 0.15% r.m.s at 7-1/2 ips.

Less than 0.20% r.m.s at 3-3/4 ips.

Less than 0.30% r.m.s at 1-7/8 ips.

Frequency Response:

30 to 22,000 Hz at 7-1/2 ips. (±3 dB)

30 to 18,000 Hz at 3-3/4 ips.

30 to 9,000 Hz at 1-7/8 ips.

Signal to Noise Ratio: Better than 46 dB

Distortion: Within 3% at 1,000 Hz OVU recording.

Cross Talk:

Less than -65dB (Monaural)

Less than -43 dB (Stereo)

Erase Ratio: Less than -70 dB for all tracks

Equalization: Correct equalization for playback of tapes recorded to the NAB curve.

Recording Bias Frequency: 60 kHz ± 5 kHz

Output (Line): 1.228 V (+4 dB) using 250 Hz OVU recorded tape. Required Load Impedance: More than 25 k-Ohms

DIN Output: 0.4 V (-6 dB) using a 250 Hz OVU recorded tape. Impedance 10 k-Ohms. Required Load Impedance: More than 50 k-Ohms

Input Level:

Line: 20 mV (-32 dB) to 2.5 V (10 dB), Impedance 390 k-Ohms

Mic: 0.5 mV (-64 dB) to 50 mV (-25 dB), Impedance 50 k-Ohms

DIN Input Level:

High: more than 20 mV (-32 dB), Impedance 390 k-Ohms

Low: more than 5 mV (-44 dB), Impedance 68 k-Ohms

F.Forward and Rewind Time: 90 seconds using a 1,200 ft. tape at 50 Hz, 75 seconds at 60 Hz

Head Phone Output: 30~40 mV, Impedance 8 Ω

Power Supply: 100 to 240 V AC, 50/60 Hz

Power Consumption: 55 VA

Insulation Resistance: More than 50 M-Ohms

Motor: Hysteresis synchronous 2 speed motor. Horse Power 1/100 HP, Power Ratio 85%. Revolution 3,000 and 1,500 r.p.m. at 50 Hz. 3,600 and 1,800 r.p.m. at 60 Hz. Condenser capacity 2.8 µF at 50 Hz, 2.0 µF at 60 Hz.

Heads:

Recording/playback head: 4 Track Gap 2 microns, Impedance 1.2 k-Ohms at 1,000 Hz

Bias head: 4 Track Gap 0.2 mm, Impedance 500 Ohms at 60 kHz

ERASE head: 4 Track Gap 0.2 mm, Impedance 500 Ohms

Record Level Indicator: Vertical indication Model “A” VU meter x 2

Transistors Used: 2SC650 (A) x 4, 2SC281 (B) x 4, 2SC458 (B) x 2, 2SC971 (2)(3) x 2

Diodes Used: 1N34A x 2, SW-05-02 x 2

Style: Portable

Dimensions: 13-1/2″ (H) x 13-1/2″ (W) x 9″ (D) (340 H x 340 W x 230 D mm)

Weight: 30.8 lbs (14 kg)

To measure the tape speed deviation, play back a pre-recorded tape at 1,000 Hz ± 0.1%. Connect the appropriate output to a frequency counter meter to measure the tape speed deviation from the pre-recorded tape.

This method utilizes a timing tape marked at intervals of 7-1/2″. Measure the running time of over 60 marked sections of tape to calculate the deviation of the tape speed. Keep in mind that timing tape stretch or contract measurement error is inevitable, so measure the total length of the tape in advance.

Playback a 3,000 Hz pre-recorded tape with a guaranteed wow and flutter level smaller than 0.07% using a wow meter.

Alternatively, record a 3,000 Hz sine wave and play it back for measurement with the wow meter. Note that in this case, the wow meter indicates a value roughly twice the value given in the specifications.

1. Set the Equalizer Switch to the “7-1/2” ips position.

2. Playback a tape containing a 250 Hz sine wave recorded at “0” VU level on a standard recorder.

3. Connect a V.T.V.M. to the line output jack of the recorder and measure its output.

4. Remove the tape and measure the noise level under the same conditions.

5. Convert each of the measured values into decibels.

1. Connect an Audio Oscillator (1 kHz output) to the X-165D input and the X-165D output to a Distortion Meter.

2. Record a 1,000 Hz sine wave at “0” VU.

3. Playback the recorded signal and measure the overall distortion factor (d).

4. Measure the noise level (d1) of the tape recorder with the tape removed.

5. Connect the audio oscillator directly to the distortion meter to measure the distortion factor of the oscillator (d2).

6. Calculate the required distortion factor (do) using the formula: do = d – d1 – d2.

(Note: Use new tape of particularly good quality for measurement.)

1. Playback a tape containing a 250 Hz sine wave recorded at 0 VU on a standard recorder.

2. Connect a V.T.V.M. to the line output jack of the recorder.

3. Measure the voltage at the output of the recorder.

1. Record a 1,000 Hz sine wave on track No. 3 at +3 VU level.

2. Remove the 1,000 Hz input signal and record under a non-input condition (record silence or erase).

3. Playback the tape on track No. 3 and No. 1 (reversed condition of tape) through a 1,000 Hz B.P.F. (Band Pass Filter, Sensitivity = 1:1).

4. Obtain the ratio between the two signals (Eo = 1,000 Hz signal output level from track 3, E2 = 1,000 Hz crosstalk output level from track 1, E1 = No-input signal record level from track 1) using the formula: C = 20 log (Eo / (E2 – E1)) (dB).

Record:

1. Connect an Audio Frequency Oscillator through an Attenuator (A.T.T.) to the Line Input of the X-165D.

2. Set the Mode/Selector Lever to the “Rec” position.

3. Supply a 1,000 Hz sine wave and adjust the line input volume so that the VU meter needle indicates “0” VU.

4. Lower the input level 16 dB using the attenuator.

5. Record spot frequencies from the audio frequency generator in the range of 30 Hz to 25,000 Hz.

Playback:

6. Connect a V.T.V.M. to the Line Output.

7. Set the Equalizer Switch to 7-1/2″ or 3-3/4″ as appropriate.

8. Playback the previously recorded tape.

9. Adjust the output level to “0” dBm at 1,000 Hz (indicated on the V.T.V.M. Range selector).

10. Playback the recorded spot frequencies under the condition set in step 9, make a note of the Output Level for each frequency, and plot the values on a graph.

Turn the RECORD/PLAYBACK LEVER (A) to the “PLAY” position. This presses the pinch wheel against the capstan to move the tape at the rated speed and engages the take-up reel drive.

To prevent accidental erasure when recording, the Record Interlock Button (F) must be depressed *before* the RECORD/PLAYBACK LEVER can be moved to the “REC” position. The safety device (G) is also depressed to operate the recording mechanism.

Turn the FAST FWD-REWIND knob (A) to the “FAST FWD” position. This engages the idler (D) with the take-up reel spindle (F) and releases the brake rollers (H and I) from the supply reel spindle (G), allowing fast winding onto the take-up reel.

Turn the FAST FWD-REWIND knob (A) to the “REWIND” position. This engages the idler (D) via the intermediate pulley (F) with the supply reel spindle (G) and releases the brake rollers (H and I) from the take-up reel spindle (J), allowing fast rewinding onto the supply reel.

Turning the stop lever to the “STOP” position causes Brake Rollers (A) and (B) to depress the reel spindles and stop their rotation. As the brake rubbers depress the plastic rollers below the reel spindles, friction is removed from the tape drive.

*Note: Supply side brake provides back tension during playback/record.

If turning the RECORD/PLAYBACK LEVER (N) to the recording position causes LEVER (a) to push RECORDING LEVER (b), but LEVER (b) does not push LEVER (c) properly, abnormal oscillation or inability to record may occur. To fix this, adjust LEVER (b) by loosening SCREW (d) and repositioning LEVER (b) so it properly engages LEVER (c) when the main lever is moved to REC, then retighten SCREW (d).

Ensure the pinch wheel shaft is perfectly aligned with the capstan shaft. Check the pinch wheel pressure using a spring scale when the unit is operating at 7-1/2 ips. The pressure should be between 1,000 and 1,150 grams. If necessary, adjust the pinch wheel load spring to achieve the correct pressure.

Ensure the take-up idler wheel is perfectly aligned with the take-up reel shaft. Adjust the idler wheel load spring so that the pressure is between 50 and 80 grams. Check pressure during both fast forward (contacts upper knurled wheel) and record/play (contacts lower knurled wheel) operations.

Ensure the rewind idler wheel is perfectly aligned with the rewind reel shaft. Adjust the idler load spring and the rewind roller so that the pressure on the knurled motor bushing is about 50 grams during rewind operation.

The intermediate wheel is located between the rewind idler wheel and the rubber ring on the supply reel shaft assembly. During rewind, it contacts both parts. Adjust the load spring of the intermediate wheel if the pressure is not sufficient (should be approximately 50 grams).

1. Fast Forward Tension (Top Felt Clutch): Install a 5-inch reel with tape having a 60 m/m diameter hub. Gently pull the end of the tape upward with a spring scale. Adjust the conical spring so the tension (friction) is between 400 and 500 grams. This prevents tape stretching during fast forward.

2. Record/Play Tension (Lower Felt Clutch): Use the same method as above. Adjust the star-shaped spring under the take-up drive wheel so the friction is between 150 and 200 grams. This provides proper slippage during record/play.

3. Rewind Tension Check: When the unit is set to rewind, the friction of this assembly should decrease to 15 to 20 grams. If not, readjust the star-shaped brake spring and the pressure of the spring retainer washer.

1. Rewind Tension (Top Felt Clutch): Place a 5-inch reel with tape having a 60 m/m diameter hub onto the supply reel table. Gently pull the end of the tape upward with a spring scale. Adjust the conical spring so the tension (friction) is between 400 and 500 grams. This protects tape during rewind.

2. Record/Play Back Tension (Lower Felt Clutch): Use the same method. Adjust the coil spring so the friction (back tension) is between 100 and 120 grams. This provides proper back tension during record/play.

3. Fast Forward Tension Check: When the unit is set to fast forward, the friction of this assembly should decrease to 15 to 20 grams. If not, readjust the coil spring and the spring retainer washer.

a) Position the Erase Head about 0.125 mm above the upper edge of the tape by adjusting the height cam provided in the lower part of the head assembly.

b) Adjust the height of the Recording/Playback Head to 0.025 mm above the upper edge of the tape by adjusting the control nut at the lower part of the head assembly.

Playback an Ampex Alignment tape (8,000 Hz) at 7-1/2 ips tape speed. Turn the alignment screw (A) until the output level of both channels reaches maximum.

Loosen the two Bias Head Screws. Move the Bias Head by hand until the clearance (f) and (g), as shown in Fig. 5 of the PDF, is 0.2 to 0.3 mm. Then tighten the screws.

Note: If clearance is less than 0.2 mm, frequency characteristic will be too low, but distortion will decrease. If clearance is more than 0.3 mm, frequency characteristic will be too high, and distortion will increase.

a) Put a resistor (10 Ω or 50 Ω) in series with the bias head.

b) Connect the signal from the resistor to the vertical input of an oscilloscope.

c) Feed a sine wave signal from an Audio Frequency Oscillator to the Horizontal Input of the Oscilloscope.

d) Tune the dial of the Audio Oscillator until the Oscilloscope displays a circular or linear pattern (Lissajous figure).

e) Read the frequency from the Audio Oscillator dial. A reading of 60 kHz ± 5 kHz indicates the Recording Bias Frequency is correct.

f) If incorrect, it can be adjusted by changing the value of condenser C-402 (standard value 3000 pF).

Connect a V.T.V.M. to the bias head. Adjust the V.A.C (Variable AC control, likely a trimmer potentiometer) in the bias oscillator circuit (located near the head assembly) until the V.T.V.M. reading equals the bias voltage stamped on the back of the head assembly. Normal bias voltage is between 60V and 70V. Acceptable terminal voltage of the erase head is between 12V and 18V.

a) Connect a high sensitivity V.T.V.M. to the Line Output Jack.

b) Playback a 250 Hz pre-recorded test tape at 7-1/2 ips.

c) Adjust VR-201 (LEFT and RIGHT CH. semi-fixed resistor 20 KΩB) on the pre-amplifier board (CD-513) so that the Line Output Voltage is 1.228 V (+4 dBm).

Note: This adjustment should only be made after “Head Adjustment” and “Line Output Level Adjustment” have been completed.

a) Connect an Audio Signal Generator and Attenuator to the Line Input. Connect a high sensitivity V.T.V.M. to the Line Output.

b) Set the Equalizer Switch and Tape Speed Selector to 7-1/2 ips.

c) Load a blank test tape (e.g., Fuji FYS-100 or Scotch No. 150).

d) Supply a 1,000 Hz signal from the audio signal generator to the Line Input.

e) Adjust each of the main front panel Volume Controls so that each of the Line Output voltages reads 1.228 V (+4 dBm) on the V.T.V.M.

f) Record the 1,000 Hz signal onto the tape at this setting.

g) Playback the recorded section and check if the Line Output Voltage is still 1.228 V (+4 dBm).

h) If the playback level is not 1.228 V (+4 dBm), repeat the recording and playback process while adjusting the internal semi-fixed resistors VR-101 (LEFT and RIGHT CH, 2 KΩ-B) until 1.228 V (+4 dBm) is obtained both during the initial recording level setting (step e) and during subsequent playback (step g).

For maximum service life and optimum performance, lubricate the following parts after each 500 hours of operation. Use only light machine oil of good quality.

Motor: (Refer to diagram in PDF for specific points)

Flywheel Assembly: 1 drop (Refer to diagram in PDF)

Rewind Idler Wheel and Wind Take-Up Idler: 1 drop

Intermediate Idler: 1 drop

Pinch Wheel: 1 drop

Also apply a liberal film of light machine grease to each roller surface of all levers and cams.

CAUTION: DO NOT OVER-LUBRICATE. WIPE OFF EXCESS OIL WITH A COTTON SWAB SOAKED IN ALCOHOL. Otherwise, excess lubricant may be scattered during operation and the rubber component parts will deteriorate.

Wipe the surface of tape heads, guide roller bearing, capstan bushing, and pinch wheel periodically with a soft cloth soaked in alcohol.

Check the following:

If No B (+) voltage supply: Check if Silicon diode (SW05-02) or R4-1KΩ (2W) is defective. Replace if necessary.

If B (+) voltage supply is present:

Check if Playback amp card and socket connection is loose. Adjust if necessary.

Check if P-10, J-10 connection is loose. Adjust if necessary.

Check transistors (TR-201, 202, 203, and TR-204).

Check if Playback head coil is open or lead wire is loose.

Check the following:

If B (+) voltage is low: Check if Silicon diode (SW05-02), R4 (1KΩ), C1 (470µF), or C2 (1000µF) is defective. Replace if necessary.

If B (+) voltage is normal:

Check for dust adhering to the head. Clean if necessary.

Check transistors (TR-201, 202, 203, and TR-204).

Check the following:

If hum decreases when playback head is grounded:

Hum bucking coil may be out of adjustment. Readjust.

Playback head shield or insulation may be defective. Replace.

If no change even when playback head is grounded:

Ground wire may be loose. Adjust.

C1 (470µF) or C2 (1000µF) may be defective. Replace.

If caused by inductive pickup: Ground the recorder or change the set position of the recorder.

Check the following:

Playback card and socket connection may be loose. Adjust.

Transistor (TR-201, 202) may be defective. Replace.

Check the following:

Dust may be adhering to the head surface. Clean.

The tape itself may be defective. Replace tape.

Check the following:

If noise is present when playing tape:

The head may be magnetized. Demagnetize head.

The tape itself may be noisy. Replace tape.

If not caused by tape:

Transistors (TR-201, 202) may be defective. Replace.

Check the following:

Poor contact between head and tape:

Dust adhering to head surface. Clean.

Back tension may be weak. Adjust tension of supply spindle.

Head angle may be incorrect. Re-adjust head angle (azimuth).

Head may be worn out. Replace.

Tape itself may be defective. Replace tape.

Check the following:

Dust adhering to head surface. Clean the head.

Defective transistors. Replace.

Head worn out. Replace.

Check the following:

If there is no VU meter indication:

VU meter itself or lead wire may be defective. Replace.

Input jack may be defective. Replace.

REC/PLAY slide switch may not function properly. Check record lever which actuates slide switch.

If VU meter indication is normal:

Transistor (TR-101) may be defective. Replace.

Bias head may not move into position. Adjust linkage.

Loose connection of P8 and J8. Adjust.

Components of oscillator circuit or oscillator coil may be defective.

Check the following:

If VU meter functions normally and recording monitor through headphones is also normal:

Faulty recording bias circuit. Check recording bias voltage and components of oscillator circuit.

Faulty recording equalization circuit. Check transistor (TR-101) and L-102 (peaking coil).

Dust adhering to head surface. Clean.

If VU meter functions normally but recording monitor through headphones is abnormal:

Over recording input level. Turn the volume down a little.

VU meter sensitivity lost. Replace VU meter.

Defective input equipment (microphone, etc.).

Check the following:

If it does not erase at all:

Erase head may be defective. Replace.

Disconnected wire of erase head or excessive dust adhering to surface of erase head. Adjust/Clean.

If erasure is incomplete:

Erasing bias voltage may be low.

Check if Transistor (TR-401, 402) is defective.

Check if Oscillator coil is defective.

Check if Erase head coil is defective.

Check the following:

Defective recording tape. Replace.

Transistor (TR-6, likely refers to a specific function/stage not detailed on provided pages) may be defective. Replace.

Head may be magnetized. Demagnetize head.

Bias voltage may be out of adjustment. Re-adjust.

Check the following:

If VU meter functions normally:

Dust adhering to head surface. Clean.

Bias voltage out of adjustment. Re-adjust.

Transistor (TR-101) defective. Replace.

Tape itself defective. Replace.

If VU meter does not indicate properly:

Loose connection of the Input jack. Adjust.

VU meter sensitivity low. Replace.

REC/PLAY slide switch does not function properly. Adjust.

Check the following:

Dust adhering to head surface. Clean.

Tape itself defective. Replace recording tape.

Back tension too weak. Adjust the tension of supply spindle.

Recording bias voltage out of adjustment. Re-adjust.

Check the following:

Difference sensitivity of the line volume itself. Replace volume control if faulty.

Recording level out of adjustment. Adjust VR-101 (2K-B).

Check the following:

Trouble with motor:

Broken field coil. Check field coil with tester, and replace motor if coil is broken.

Defective motor starting capacitor C6. Replace C6.

Rotor shaft dragging due to lack of oil. Overhaul motor. Clean and re-lubricate oilite metal.

Some foreign matter exists between rotor and stator. Check and eliminate foreign matter for free rotation of rotor.

Trouble with power transmission mechanism:

Broken capstan drive belt. Replace belt.

Capstan drive belt off of driving position. Place belt in position.

Motor bushing slipping on motor shaft. Tighten mounting screw.

Oil adhering to motor bushing and/or flywheel. Wipe off oil with cotton swab soaked in alcohol.

Check the following:

Trouble with motor:

Decreased motor torque. Check motor torque and replace motor if necessary.

Defective C7 (likely capacitor). Replace C7.

Motor bushing slipping on motor shaft. Tighten mounting screw.

Trouble with power transmission mechanism:

Capstan drive belt stretched. Replace belt.

Oil adhering to motor bushing and/or flywheel. Wipe off oil.

Capstan bushing slipping on flywheel shaft. Tighten capstan mounting screw.

Excessive tension in Take-up/Supply reel table assembly. Readjust tension.

Oil adhering to capstan and/or pinch wheel. Wipe off oil.

Insufficient pinch wheel pressure. Check and re-adjust pinch wheel pressure.

Check the following:

Reel shaft dragging due to lack of oil. Check take-up reel shaft assembly.

Take-up idler wheel does not rotate properly. Check idler wheel. Replace if necessary.

Oil adhering to idler wheel and roller on take-up reel shaft assembly. Wipe off oil.

Take-up idler wheel does not keep good contact. Check idler tension spring. Replace spring if necessary. Check level “G” (referencing a specific mechanical alignment).

Check the following:

Trouble with motor:

Rotor shaft dragging due to lack of oil. Overhaul motor. Clean and re-lubricate oilite metal.

Defective motor starting capacitor (C6a, C6). Replace (C6a, C6).

Fluctuation in power supply: Check line voltage and cycles. Use voltage regulator if line voltage is lower than standard.

Trouble with power transmission mechanism:

Capstan drive belt stretched and slipping on motor bushing. Replace belt.

Capstan drive belt not in correct driving position. Place belt in position.

Oil adhering to motor bushing and/or flywheel. Wipe off oil.

Check the following:

Trouble with motor:

Decreased motor torque. Check motor torque.

Defective motor starting capacitor (C6). Replace C6.

Trouble with power transmission mechanism:

Take-up, supply reel shaft dragging or excessive tension. Check reel shaft assemblies. Replace reel shaft assembly if tension not adjustable.

Capstan drive belt stretched and slipping. Check belt.

Unbalanced flywheel rotation. Check balance. Replace flywheel.

Rubber on pinch wheel deteriorated. Check rubber on pinch wheel and replace pinch wheel.

Pinch wheel or tape guide does not rotate smoothly. Check and replace defective part. Clean and re-oil if it again provides smooth rotation.

Dust on heads. Clean heads.

Insufficient pinch wheel pressure. Re-adjust pinch wheel pressure.

Capstan bushing slipping on flywheel shaft. Tighten capstan mounting screw.

Worn-out idler wheel or no oil. Replace worn-out idler. Lubricate oilite metal in center idler.

Check the following:

If Take-up reel shaft does not rotate even without tape:

Trouble with power transmission mechanism:

Oil adhering to take-up idler wheel or motor bushing. Wipe off oil.

Loose motor bushing. Tighten motor bushing mounting screw.

Take-up idler wheel does not function properly. Check and readjust idler wheel.

Take-up reel shaft assembly does not function properly. Check, clean and re-oil reel shaft assembly.

Check lever “G” (referencing specific mechanical linkage).

If Take-up reel shaft does not rotate when tape is placed on unit:

Trouble with motor:

Decreased motor torque. Check motor torque. Replace motor if required.

Defective motor starting capacitor (C6). Check and replace C6.

Trouble with power transmission mechanism:

Excessive slippage of clutch material (felt) in take-up reel shaft assembly. Check take-up reel shaft assembly.

Tape guide roller does not rotate smoothly. Check guide roller. Re-Oil or replace.

Defective reel: Take-up warped and sticking to deck top panel. Check and replace reel.

Check the following:

If Supply (rewind) reel shaft does not rotate even without tape:

Trouble with power transmission mechanism:

Oil adhering to rewind idler or motor bushing. Wipe off oil.

Intermediate idler (black bakelite wheel) not working correctly. Check internal idler.

Loose motor bushing. Tighten motor bushing mounting screw.

Rewind idler does not rotate or not in position. Check rewind idler. Clean and re-oil.

Supply reel shaft assembly does not rotate smoothly. Check supply reel shaft assembly. Clean and re-oil.

If Supply (rewind) reel shaft does not rotate when tape is placed on unit:

Trouble with motor:

Decreased motor torque. Check motor torque. Replace motor if not repairable.

Defective motor starting capacitor C6. Replace C6.

Trouble with power transmission mechanism:

Excessive slippage of clutch material (felt) in supply reel shaft assembly. Check supply reel shaft assembly.

Tape guide roller does not rotate. Check guide roller. Re-oil or replace.

Defective reel: Supply (rewind) reel warped and sticking to deck top panel. Check and replace reel.

Decreased back tension of take-up and supply reel shaft assemblies. Disassemble reel shaft assemblies and strengthen back tension (adjust clutch springs).

Check the following:

Excessive slippage of felt clutch material in take-up and rewind reel shaft assemblies. Readjust slippage of felt clutch material. Replace defective reel shaft assembly if this readjustment is difficult.

Reels of different sizes are used (e.g., 5″ on take-up, 7″ on supply). Always use reels of same size on both sides.

Check the following:

Worn-out brake shoes. Check and replace brake shoes.

Oil adhering to surface of brake shoes. Wipe off oil with cotton swab soaked in alcohol.

Loose brake shoes. Tighten brake shoes mounting screw.

Brake lever does not function properly. Check and re-adjust brake lever.

Worn-out and rugged idler wheel. Check idler wheel.

Check the following:

Loose motor mounting screw. Tighten mounting screw.

Defective motor starting capacitor C6. Replace C6.

Loose oil cover mounting screw. Tighten mounting screw.

Check the following:

Deposit of dust on heads. Clean heads.

Recording tape is being charged with static electricity. Replace recording tape.

Excessive heat on head surface after continued operation. Check tape head.

Old and worn-out recording tape. Inspect recording tape.

Inferior recording tape. Use recording tape of good quality.

Check the following:

If Automatic stop lever moves normally:

Micro switch (SW-5) does not work properly. Check SW-5.

If Automatic stop lever does not move or is sticky:

Broken lever spring or lever spring not in position. Check lever spring.

Automatic stop lever sticks to rear deck panel. Check rear side of deck sub-plate.

Check the following:

No lubricant on cycle conversion lever. Relubricate lever.

Eccentric or bent cycle conversion lever. Check cycle conversion lever.

Capstan drive belt not on driving track of flywheel. Check capstan drive belt.

Loose motor bushing. Tighten mounting screw.

Loose motor mount screw. Tighten mounting screw.

Oil on motor bushing or on flywheel. Wipe off oil with cotton swab soaked in alcohol.