No pilot light, no tape motion, and no amplifier hiss
- Defective power supply cords
- Poor power connections
- Defective ac-dc selector switch
- defective auto-boat jack
- Defective cartridge switch
No operation with dc power source
- Defective ac-dc selector
- Open auto-boat jack
- Broken or open dc power cord
- Defective batteries
- Improper seating of batteries
- Reverse-voltage diode
- Diode shorted or open
Power light on but no tape motion
- Broken, loose or worn drive belt
- Loose motor pulley
- Frozen or burned out motor
- Frozen capstan-flywheel assembly
- Open wiring to motor circuits
Wow or flutter
- Poor lubrication
- Defective or oily capstan
- Loose or worn drive belt
- Oil on drive belt
- Belt riding high on motor pulley
- Defective motor
Crosstalk
- Height adjustment off
- Jammed tape head assembly
Excessive noise
- Worn or dry motor bearing
- Seized or frozen capstan
- Defective motor
- Erratic or worn volume control
Will not change channels
- Shorted or open solenoid circuits
- Shorted diode across solenoid
- Open selector switch
- Defective track-shift mechanism
Channel indicator defects
- Open channel lamp circuit
- Defective channel lamp switch
- Burned out lamps
- broken indicator lamps
- Slipping shaft to lamp switch
- Dirty lamp switch contacts
- Broken or defective rubber channel belt
No sound
- Defective transistors
- Defective tape head
- Leaking or open coupling capacitor
- Shorted bypass capacitors
- Open B+ circuit to amplifier
- Defective power cord
Weak or low sound
- Defective or dirty tape head
- Defective transitors
- Open bypass or coupling capacitors
- Shorted bypass or coupling capacitors
- Tape head out of adjustment
Distorted Sound
- Leaky or shorted transistor
- Leaky coupling capacitors
- Burned or changed resistance of bias and emitter resistors
- Heatsink shorted to power transistors
- Very dirty tape head
- Open or erratic bias controls
Amplifier has high-pitched tone
- Improper head azimuth adjustment
- Defective tape head
- Open capacitors in preamp
- Open or poor lead connections
Low treble
- Oxide deposit on head
- Worn head surface
- Head out of alignment
Abnormal oscillations
- Poor head leads
- Filter and decoupling filters
- Resistance change or burned decoupling filters
- Open or poor volume control connections