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:
Power Transistor is compensated properly.
The circuit has been corrected so that the temperature rise of the
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.)
______________________________________________________________________________________
The information contained in this document is intended for the exclusive use by DENON Authorized Service Centers and their
employees. This document may contain information that is privileged, confidential and may be protected from disclosure under
applicable laws and terms of the DENON Service Agreement. Any distribution, disclosure, dissemination or copying of this
document and the information it contains is prohibited. No responsibility will be accepted by DENON for any damage, injury or loss
resulting from the misuse of the information contained in this document.
CONFIDENTIALITY NOTICE:
3) Adjustment of the Idling Voltage: Turn the Power of the unit on. Then, after 10
minutes, adjust the Voltage to 2.0 mV ±0.5 mV. (Refer to the Service Manual for
adjustment procedure.)
4) Re-assemble the Main P.W. Board in the unit and attach the Top Cover.
Parts:
Ref# Description Part Number
Q103C, FL, FR,
Transistor, 2SC3964 00D 963 0280 107
SL, SR, SBL and
SBR
R101C, FL, FR,
SL, SR, SBL and
680Ω Resistor,
RD14B2E681JT
00D 241 2398 913
SBR
There is SB instead of SBL and SBR on the models AVR-1505 and 1705.
Serial Number Range:
______________________________________________________________________________________
The information contained in this document is intended for the exclusive use by DENON Authorized Service Centers and their
employees. This document may contain information that is privileged, confidential and may be protected from disclosure under
applicable laws and terms of the DENON Service Agreement. Any distribution, disclosure, dissemination or copying of this
document and the information it contains is prohibited. No responsibility will be accepted by DENON for any damage, injury or loss
resulting from the misuse of the information contained in this document.
CONFIDENTIALITY NOTICE:
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