Troubleshooting

Trouble

Checkpoints and Possible Cause

Reference Waveform

Does not work at all (Pilot lamp does not light)

• Check the voltages VA (+5V), VE (+3.35V), VC (+5V) and VD (+5V).

• Check the reset and APO signals.

• Faulty parts: Transistors T1 ~ T4, Power switch, or CPU

t

Does not work at all (Pilot lamp lights)

• Check the voltages VH (+7.5V), VC (+5V) and VD (+5V).

• Check the clock pulse and key common signals.

• Faulty parts: Transistors T5 ~ T8, Ceramic Trimmer

VCT84K, or ROM (LSI 4).

Waveforms (T), ®

Preset tone does not sound on PLAY mode

• Check the analog signal at base of transistor T11 or Power amp. (IC1).

• Faulty parts: Transistors T7 -T9,T11, CPU (LSI 1) or

Power Amp. (IC1).

Waveform(5)

Chord or Bass tone does not sound on CHORD mode

• Check the analog signal at collector of transistor T18 or T23.

• Check the analog signal at source of FET T10.

• Faulty parts: Transistors T18 ~ T23, T10, or Analog

Switch (IC2).

+1 -1

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