Tuesday, December 22, 2015

YAMAHA GX-505 test mode and power amplifier circuit diagram

YAMAHA GX-505

TEST MODE
To facilitate inspection, measurement and location of any faulty point, 6 types of built-in Test Modes are provided, one for each section.
# System Test Mode : Test mode for the system section. It is also used when entering the test mode for each section.
# Receiver Test Mode : Test mode for the receiver section
# Tape Test Mode : Test mode for the deck section
# CD Test Mode : Test mode for the CD section
# MD Test Mode : Test mode for the MD section (unused for this unit)
# All Function Test Mode : Test mode for all functions
SYSTEM TEST MODE
This test mode is used for the system section. Also, this mode must be executed first when entering the test mode for each section.
Starting Procedure
In the STANDBY mode, press the STANDBY/ON button while pressing the RANDOM button and the PLAY/ PAUSE(CD) button simultaneously. Once the SYSTEM TEST MODE is set, causal factors for the previous power off appear on the FL display.
Causal factors for power off at starting
Display
Description
<Key Operate
Power off by button operation
<Off Timer
Power off by Off Timer setting
<Sleep Timer
Power off by Sleep Timer function
<Auto Off
Power off by Auto Power Off function
<I-Protect
Power off by detection of an abnormal current value
<V-Protect
Power off by detection of an abnormal voltage value
<Temp Over
Power off by detection of an abnormal temperature value
<AC Cut
Power off by AC power cut

Operation Procedure (Selection/finalizing of TEST MODE for each section)
1) Select the TEST MODE by the section name, pressing the INPUT (up) or INPUT (down) button.
2) Pressing the MUSIC button will shift the mode to the selected test mode.
RECEIVER TEST MODE
When the RECEIVER TEST MODE is set through the SYSTEM TEST MODE, “01 G.E.TEST” appears on the FL display. (01 is the test program No.) Test programs from 01 to 25 are incorporated in RECEIVER TEST MODE.
Operation Procedure (Selection/execution of Test Program)
1) Select the test program by pressing the TAPE (up) or TAPE (down) button.
2) Pressing the STANDBY/ON button will execute the selected test program.
3) Repeat selection/execution of the test program as necessary.
TAPE TEST MODE
When the TAPE TEST MODE is set through the SYSTEM TEST MODE, “Tape Test XXXX” appears on the FL display. (XXXX is the counter value.)
The operating condition of the deck section will be as follows.
# When the reverse mode is set to “endless”, the number of playback repetition becomes unlimited.
(It is set to “8” times in the normal operating mode.)
# When in the REC mode, AUX/MD is used automatically for the input source.
CD TEST MODE
When the CD TEST MODE is set through the SYSTEM TEST MODE, “00 TM1 00: 00” appears on the FL display.
The CD TEST MODE is enabled. Each button operates as follows for each mode. The MODE No. is increased by pushing "+10" button.
ALL FUNCTION TEST MODE
When ALL FUNCTION TEST MODE is set through SYSTEM TEST MODE, “AUX/MD” appears on the FL display.
The operation condition in this mode will be as follows.
# AUX/MD is used as the input source of the receiver section, which is then set to the Dolby Pro Logic mode (GX-
505VCD only).
# When a CD is loaded, Full Repeat Play is executed automatically for it.
# When a cassette tape is loaded, Endless Rec Play is executed by the cassette deck automatically.
POWER AMPLIFIER CIRCUIT 
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