Master Electronics Repair !

Welcome to Master Electronics Repair! website.Here you will find:Service Modes, Circuit Diagrams,Service manuals, Firmware Update procedure, Disassemble procedure, Universal remote control setup codes, Troubleshooting, Diagnosing, Measuring, and more.... of many of LCD/LED TV/Displays,others various electronic apparates,trough many technical notes and tips/tricks to help repairing/fixing Troubles/ faults,for electrical technicians.This site helps you to save the Earth from electronic waste!

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!

Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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Thursday 7 March 2019

YAMAHA GX-505 TEST MODE AND POWER AMPLIFIER CIRCUIT DIAGRAM

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

CLICK ON THE IMAGE TO ZOOM IN