ONKYO HTP-750B
Manual de Servicio

HTP-750 ADJUSTMENT PROCEDURE
SKW-750 : POWERED SUBWOOFER / ADJUSTMENT OF IDLING CURRENT
[When] 1. Exchange transistors (Q505 - Q519). 2. Exchange MAIN PC board ass'y (NAAF-8829). [Procedure] <Note> No speaker load and No input signal. 1. Short test point P631 for amplifier is under active mode. 2. Adjust the trimming resistor R544 so that the reading of multimeter becomes 52 ohm to 53 ohm. 3. Connect the DC voltmeter to test point P531. <Fig-1> 4. Connect the AC power cord into a wall outlet. 5. Press POWER button to turn on the unit. (MPA type only) 6. Confirm the voltage of above point after 6 minutes to 8 minutes. (Heat running) 7. When less than 3.20 mV : Readjust the trimming resistor above so that the voltage becomes 4.5 mV to 5.0 mV. When 3.30 mV to 5.20 mV : Not necessary to adjust. When 5.21 mV to 10.0 mV : Readjust the trimming resistor above so that the voltage becomes 5.0 mV to 5.5 mV. When 10.1 mV to 20.0 mV : Readjust the trimming resistor above so that the voltage becomes 5.6 mV to 6.0 mV. 8. Press POWER button to turn off the unit. (MPA type only) 9. Disconnect the DC voltmeter. 10. Disconnect the AC power cord from a wall outlet.
100 ohm (1/4W) DC voltmeter

<Fig-1>

Trimming resistor

Test point

Test point P531

R544

P531

MAIN PC board ass'y "NAAF-8829"

Test point

P631
Short