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........ . . . . . .....
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Tuesday 26 February 2019

SONY WEGA - CONTINUOUS TUNING. NO TUNNIG LOCK. [SONY WEGA KV-TG-21L70 _ KV-TG21M80 _ KV-TG21P52]

SONY WEGA - CONTINUOUS TUNING. NO TUNNIG LOCK. [SONY WEGA KV-TG-21L70 _ KV-TG21M80 _ KV-TG21P52]


In auto serch mode, set tunes to  channels, but not lock them in memory.  Tunig process goes on and on.  No end.

This fault is mainly with the main system control section and tuner.  check whether you can see glimps of stations, as set tunes on.  If you can see it, make sure that the tuner to your TV is working fine, and the tuned stations are not stored in memory.
This is a bus type chasis.  That is, all the other ICs are controlled by main system control IC [IC 001 _ CXP85***], by a data stream of two lines,  serial clock and serial data from pins 55 & 53 respectively.  whan a station is tuned in, the data will be transfered to it main system memory IC [IC 003 - M24C08-BN6(A)].
 Check the voltage to this memory IC  There are four pins (1,2,3&4) are connected together to ground. Pin number 8 of this IC gets 5VDC; and pin 5 gets data from main system IC, and pin 6 gets serial clock pulse.  Check the voltages of these pins. Voltages at pins 5&6 should be around 4.3VDC.  If pin number 8 have 5VDC and other two pins stated above gets 4.3VDC, and still the channels can't be memorized, the memory IC should be suspected.
Before mak it sure, chck thefrequency of these data and clock input pins [square wave], with the help of an oscilloscope, if available. If you haven't this testing equipment, try repalce the IC.  This IC is very cheap to buy and available from most of the electronic spare part selling shops at your town.  Make sure to use the exact number as specified, otherwise, the set will even refuse to swtcih ON. In most cases, to my service experience, I've found this IC to be faulty.
This is the image of the said IC.   See, it is a surface mount type device;  special care should be taken while desolder it out from the ciruit board, and to resolder a new one in place