Onkyo HTP 780 Service Manual

Page 1

ONKYO SERVICE MANUAL

7.1-CH HOME THEATER SPEAKER PACKAGE

Front Speakers (L / R)
"SKF-780"

MODEL HTP-780(B)

HTP-780

Ref. No. 4229
062010

Powered Subwoofer
® @ "SKW-780"

Surround Speakers (L / R)
"SKR-780"
Center Speaker
"SKC-780"

Surround Back Speakers (L / R)

"SKB-780"

Black model

B MDC 120V AC, 60Hz

SAFETY-RELATED COMPONENT
WA R N I N G ! !

COMPONENTS IDENTIFIED BY MARK A ON THE
SCHEMATIC DIAGRAM AND IN THE PARTS LIST ARE
CRITICAL FOR RISK OF FIRE AND ELECTRIC SHOCK.
REPLACE THESE COMPONENTS WITH ONKYO
PARTS WHOSE PART NUMBERS APPEAR AS SHOWN
IN THIS MANUAL.

MAKE LEAKAGE-CURRENT 0R RESISTANCE
MEASUREMENTS TO DETERMINE THAT EXPOSED
PARTS ARE ACCEPTABLY INSULATED FROM THE
SUPPLY CIRCUIT BEFORE RETURNING THE
APPLIANCE To THE CUSTOMER.

ONKYO®

IMAGINATIVE SIGHT SI SOUND

Page 2

ADJUSTMENT PROCEDURE

SKW-780 : POWERED SUBWOOFER / ADJUSTMENT OF IDLING CURRENT

[When]

1. Exchange transistors (Q505 - Q519).

2. Exchange MAIN PC board ass'y (NAAF-8829).

[Procedure]

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.

4. Connect the power cord into the AC outlet.
5. Confirm the voltage of above point after 6 minutes to 8 minutes. (Heat running)
6. When less than 320 mV : Readjust the trimming resistor above so that the voltage becomes 4.5 mV to 5.0 mV.

When 330 mV to 5.20 mV : Not necessary to adjust.

HTP-780

When 521 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.
7. Disconnect the power cord from the AC outlet.
8. Disconnect the DC voltmeter.

Trimming resistor

R544

Test point
P531

100 ohm
(1/4W)

DC voltmeter

o

Test point 00

P531

O

MAIN PC board ass'y "NAAF-8829"

Test point
P631

Short