Pioneer IS-21T Service Manual - Page 21

XC-IS21T 6. ADJUSTMENT For adjustment, use the stereo power amplifier (M-IS21). 6.1 DECK SECTION 6.1.1 Adjustment Condition (1) The ground at the time of adjustment shall be W166. (Refer to Fig. 6-3). (2) Clean the heads and demagnetize them using a head eraser. (3) Set the measurement level to 0 dBV = 1 Vrms. (4) Use the specified tape for adjustment. Use the labeled (A) side of the test tape. NCT-111 : For Tape Speed adjustment STD-331E : For Playback adjustment STD-632 : Normal blank tape * As the reference recording level is 250 nwb/m for STD- 331E, the recording level will be higher by 4 dB for STD- 331B (160nwb/m). When adjusting, pay carefull attention to the type of tape used. (5) Provide yourself with the following measuring devides: ÷ AC millivoltmeter ÷ Low-frequency oscillator ÷ Attenuator ÷ Oscilloscope (6) Adjust both right and left channels unless otherwise specified. (7) Turn the DOLBY NR switch off unless otherwize specified. (8) Warm up the unit for several minutes before adjustment. In particular, be sure to warm up the unit in the REC/PLAY mode for 3 to 5 minutes before starting recording/playback frequency characteristics adjustment. (9) Always follow the indicated adjustment order. Otherwise, a complete adjustment may not be achieved. 7 List of Adjustments ¶ Playback Section (1) Tape Speed Confirmation (2) Head Azimuth Adjustment (3) Playback Level Adjustment ¶ Recording Section (1) Recording Bias Adjustment (2) Recording Level Adjustment PLAY BACK 250 3dB 12.5k 10k 3dB 4dB RECORDING 250 3dB 12.5k 10k 3dB 5dB 0 dB 30s 315 Hz 0 dB: 315 Hz, 250 nwb/m 30 s 30 s 6.3 kHz 10 kHz Fig. 6-1 Frequency Characteristics Dolby noise reduction manufactured under license from Dolby Laboratories Licensing Corporation. "DOLBY" and the double-D symbol are trademarks of Dolby Laboratories Licensing Corporation. 30 s 315 Hz 10s 10s ...10s -20 dB 14 kHz 12.5 kHz 10 kHz 8 kHz 6.3 kHz 4 kHz 2 kHz 1 kHz 500 Hz 250 Hz 125 Hz 63 Hz 40 Hz Fig. 6-2 Test Tape STD- 331E 51