To set the amplitude of the RF signal to the optimum value.
Symptoms when incorrectly adjusted
Drop-outs occurs frequently.
Connect the oscilloscope to TP1-1 (RF). Use the following oscilloscope settings:
Channel 1: Probe x10, 50mV and 2ms/div (if the oscilloscope is faster than 20MHz turn on the bandwidth limiter for the channel).
Put the player in the following condition:
- Normal mode
- Still mode
Play the test disc in normal mode and search for frame 15,000.
Note: The original service manual states that the RF level should be 300mV peak-to-peak and adjustment should be made to VR1 in the PREB assembly. Since there is no PREB assembly in the player and the RF levels cannot be raised to 300mV, this information is likely incorrect (or simply copied from another service manual). Therefore, the following is the author’s recommended procedure.
Adjust VR1 on the FTSB module so that the amplitude of the RF signal becomes 200 mV peak-to-peak +- 20 mV as shown in the following trace: