Denon AVR-885, AVR-2105, AVR-785, AVR-1905, AVR-685 Service Bulletin

100 Corporate Drive Mahwah, NJ 07430

Service Bulletin

No. : OST-F1034

Date: November 24, 2009

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Model: AVR-885, AVR-2105, AVR-785, AVR-1905, AVR-685, AVR-1705,

AVR-485, AVR-1505

Subject: Countermeasure for preventing the Power Amplifier Circuit from breaking down.

Symptom: The transistor that is used to compensate the temperature rise of the Power Transistor in the Output Stage is incapable of following the rapid temperature rise. Because the temperature rise is not compensated for properly the Power Amplifier Circuit may be damaged

Solution: The circuit has been corrected so that the temperature rise of the Power Transistor is compensated properly.

MODIFICATION: (Upon repair) Replace all Q103 Transistors and all R101 resistors in the unit with the improved parts. (The replacement of the transistor and resistor is applicable to each channel of C, FL, FR, SL, SR, SBL and SBR.)

• Modification Procedure:

1)Remove the Top Cover, and remove the Main P. W. Board from the unit. (Refer to the Service Manual.)

2)Replacement of the Transistors and the Resistors:

(a)Remove the Q103 2SD947F Transistor (Q103FL, Q103FR, Q103C, Q103SL,

Q103SR, Q103SBL and Q103SBR) and replace it with the 2SC3964 Transistor. (There is SB instead of SBL and SBR on the models AVR-1505 and 1705.)

(b)Remove R101 2.7kΩ resistor (R101FL, R101FR, R101C, R101SL, R101SR,

R101SBL and R101SBR) and replace it with the 680Ω resistor. (There is SB instead of SBL and SBR on the models AVR-1505 and 1705.)

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