REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

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 !

Wednesday, 13 March 2019

AV RECEIVER PROTECTION MODE HOW TO FIND THE FAULT

AV RECEIVER PROTECTION MODE

                                                AV RECEIVER PROTECTION MODE

How to find the fault

First of all remove all the speaker connections from the amplifier. After that power the amplifier and check the protect show or not. If not, then any of the speakers is damaged. If then also it shows protect you have to check the amplifiers hardware.
AV receiver shows protect mode, when there is a hardware fault in side it. It’s a warning that some thing is wrong.
Normally AV receiver’s show this when any of the output amplifiers get some problem. There are six amplifiers in this AV receiver. May occur when the output diver transistors of any of the amplifier become shorted. if the output transistor get shorted this will lead to flow of current through the speakers. To prevent this there is a protection circuit for each channel. One combined output of this protection circuit is connected to the system control. When the any of the output amplifier fails, the protection circuit detects it and switch of the speaker and sent data to the system control. When the system control gets this data it will give a warning to the customer through display that PROTECT. 
You have to check the amplifier. 
For that you need Digital Multimeter, Soldering iron screwdrivers etc
open the amplifier, then power it on. Connect the negative terminal of the multimeter any where in the chase (metal body of the amplifier). Then connect the positive terminal to all the output transistors emitter pin one by one. The voltage should be bellow 0.5V. If any of the emitter of the transistor shows voltage more than 0.5V., then that amplifier stage is faulty. Remove the transistors and check it. if it is shot then replace with a new one. 
After replacing the transistors do not power up the amplifier directly from the main. You have to put a bulb of 60 watts in serial. 
You can do this easily remove the mains fuse. put the bulb in a holder. now you have to wire from the holder. Connect one of it to the one end of the fuse holder and the other wire to the other end of the fuse holder. Why using a bulb is, if there is any further problem in the amplifier stage on which the transistors replaced, there is a possibility of the new transistor get damage. if we use a bulb in serial with its mains supply ,when any overload in the amplifier occur the bulb will drop the current, by lighting itself.
After connecting the bulb in serious power on the amplifier. watch the bulb. It should light for one or two second and go dim. If so check the display, is there is protect mode is on or not. If not and come back to normal operation, then remove the power, remove the bulb insert fuse and check
connect the power and check.
If the bulb shows bright light then there is some component also faulty in the same amplifier section . After removing the power you have to check again the amplifier stage of which the transistor is replaced, for any other faulty components.
Posted By: FRANK at 05:47
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