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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All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Tuesday 5 March 2019

BOSE LIFESTYLE SEREO AMPLIFIER – BOSE SA2 - BOSE SA3 – TEST PROCEDURE – HOW TO DISASSEMBLE – AUDIO SYSTEM REPAIR AND SERVICE

BOSE LIFESTYLE SEREO AMPLIFIER – BOSE SA2 - BOSE SA3 – test procedure – How to disassemble – Audio system repair and service

Category: Audio System Repair and Service

Contents of this article

Test procedure
How to disassemble

BOSE SA2 - SA3

TEST SET-UP

Equipment Needed:
# DC Power Supply
# Audio signal generator
# 2 - 6 Ohm, 100 Watt load resistors
# Audio input cable part number 278128
# Connector plug part number 272953-04

DIP Switch Settings

A Up Stereo/Mono switch (up is stereo mode)

B Down Enable/Disable auto-detect of RCA audio input (up is disabled)
C Down Slave/Master switch (down is master mode)
6 Down Room Address 1st bit (MSB)
7 Down Room Address 2nd bit
8 Down Room Address 3rd bit

9 Up Room Address 4th bit (LSB)

Set up the unit under test as described below.
1. Set the DIP Switches as described above.
2. Connect the DIN connector of cable part number 278128-001 to the amplifier Bose link DIN input connector.
3. Connect the left and right RCA connectors to a signal generator.
4. Load the left and right outputs with a 6 Ohm, 100W resistor by using connector plug part number 272953-04.
5. With the unit unpowered apply a 1.6 VDC to PIN 6 of the bottom DIN connector.
Note: The microcontroller will respond by placing the unit in a special test mode. The unit will power ON (LED will turn to solid green), source channel 2 will be selected, volume level will be set to maximum and the amplifier outputs will unmute.
6. Apply AC Power.
Note: The 2.5 VDC must be applied before AC voltage is applied.
LED Status Indicator
The green LED, located next to the dip switches on the rear of the unit, indicates the operational mode of the amplifier.

LED activity	Mode
Constant slow blinking	Power off (Standby)
Continuously lit	Power on
Lit but rapidly flickering	Slave
Blinking Quickly	Receiving commands

DISASSEMBLY PROCEDURES - Bose SA2

PCB Disassembly and Transformer Removal
1.1 On the rear panel, remove the phillips-head screw identified below that secures the AC power jack to the amplifier housing.

1.2 Remove the six phillips-head screws indicated to remove the amplifier housing bottom panel. Lift off the bottom panel.
Note: The transformer is secured to the amplifier housing by four of these screws.

1.3 Remove the four phillips-head screws that secure the IC pressure bar to the amplifier housing. Lift off the pressure bar.
1.4 Remove the three phillips-head screws that secure the PCB assembly to the amplifier housing.

1.5 Lift the PCB assembly and transformer up and out of the amplifier housing. Make sure that the rear panel connectors clear the housing.
1.6 Make a note of how the transformer is plugged into the PCB assembly and remove the two transformer cables from the PCB assembly jacks at J2 and J3.

DISASSEMBLY PROCEDURES - Bose SA3

PCB Disassembly and Transformer Removal
1.1 On the rear panel, remove the phillips-head screws identified below that secures the AC power jack to the amplifier housing as identified below.

1.2 Remove the four phillips-head screws indicated to remove the bottom panel to the amplifier housing. Lift off the bottom panel.
Note: The transformer is secured to the amplifier housing by two of these screws.

1.3 Remove the four phillips-head screws that secure the plate clamp to the amplifier housing. Lift off the plate clamp.
1.4 Remove the three phillips-head screws that secure the PCB assembly to the amplifier housing.

1.5 Remove the two phillips-head screws identified, these are the remaining two screws that secure the transformer to the amplifier housing.

1.6 Lift the PCB assembly and transformer up and out of the amplifier housing. Make sure that the rear panel connectors clear the housing.

1.7 Remove the two transformer cables from the PCB assembly jacks at J2 and J3.