No Display In TV Due To EEprom IC Fault

By on January 16, 2019
No Display In TV Due To EEprom IC Fault

 

 

 

 

 

 

 

 

 

 

 

haeir CRT tv repair

This Haier TV came in with the complaint of no sound but have OSD menu. When the TV antenna was connected the picture appeared for a while then went off (black screen) and could only see the volume once the volume control was pressed.

eeprom ic fault in tv

The below picture was just before it went off after the antenna was connected. Observe that the picture was also not full screen.




It was just half screen and did not fill up the whole screen.

bad eeprom ic in tv

Next, the TV cover was removed and it  was full of dirt and dust and I had to clean it with a brush and a vacuum cleaner.

dirty crt tv board

From my many years of repairing CRT TV, the chances was high either the microprocessor or the TV EEprom data could have been corrupted.




Since getting a new EEPROM IC was easy thus I replaced the EEprom first and see how it goes.

eeprom ic faulty in tv

The new EEPROM IC part number was 24C08 and it was a blank IC.

eeprom ic 24c08

Once the EEprom IC was replaced with a new one, I powered up the TV and saw that the picture appeared half horizontally and need to change the language setting. I was on the right track because if  after changing the EEprom IC with the same exact symptom as the original one then possible I have to replace the microprocessor.

crt tv eeprom ic corrupted

Now, in order to enter into the TV service mode I had to press Volume button and OSD Menu button in the remote control  at the same time for about 15 seconds. After that the TV switched to factory service mode where I can change the RGB setting and the height adjustment of the TV-See the photo below:

remote control setting for tv

eeprom tv setting

Once the adjustment was done, the setting was save in the EEPROM IC and the picture was back to normal again-see the photo below:

crt tv repair

Conclusion- Many times the TV problems was not related to hardware failure. In fact it was due to the corrupted of the programs or data of the EEPROM IC. If you read my previous articles on “No sound symptom in TV” you would surely know the impact of a corrupted EEPROM IC. If you wish to learn about CRT TV repair , you can check out Humphrey’s ebook on CRT TV repair HERE

suranga

This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.




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7 Comments

  1. Parasuraman S

    January 16, 2019 at 4:55 pm

    Good job, Suranga! EEPROM fault is not that easy to find out! You are an expert!

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  2. Albert van Bemmelen

    January 16, 2019 at 6:22 pm

    Understood. The screen was first partly black on the left side and after replacing the eeprom by a new one the screen setting changed by only showing a top partly black screen instead. And you were almost sure that it was not the processor that was at fault, and that reprogramming its eeprom settings would work. Very professional repair!

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  3. Robert Calk Jr.

    January 16, 2019 at 8:32 pm

    Good job, Suranga.

    Likes(0)Dislikes(0)
  4. Christian Robert Adzic

    January 17, 2019 at 7:58 am

    Hi!
    I really appreciate your repairing, good job done and another tool saved.
    I have several questions or I'm maybe a bit confused.
    I would like to dig a bit deeper in this situation.
    So, you was found an eeprom with a corrupted data.
    Ok, that makes sense to have an irregular setup for the unit.
    You solved the problem by changing the old eeprom with a new empty eeprom.
    The cpu should recognize the empty eeprom and fill it with the values of the new setup.
    This is the point where the repairing was successfully done.
    so, you had a corrupted eeprom content but not a bad eeprom ic itself on the hardware level.

    From my point of view, I have several questions:
    Why you not tried to r/w the old eeprom?
    With a r/w you could get the data from the eeprom, even if the eeprom was corrupted, but that is not the main point of the r/w I'm requested.
    You could erase the content of the eeprom and you would have a blank eeprom as the new one and you would also repair the unit, without to use a new eeprom.

    Even if the content was corrupted in the old eeprom, when you make new settings and save them, the cpu should rewrite the eeprom content as it is done when you interchanged that two eeprom.
    Actually, if this is working this way, than the corrupted data in the eeprom would be overwritten with good data and the unit should work again.
    In this case no need to change the eeprom.

    What could cause that kind of data corruption?
    I think the cpu firmware takes care about data corruption and there should
    be some sort of data integrity check in the system like a really often used
    CRC check and the checksum is written inside the eeprom.

    I'm a bit suspicious does the manufacturer used an 8k eeprom to save only lets say 200 byte long parameters.
    There must be much more think in there.
    Do you ever investigated the content of the eeprom?
    I would like to see some of them.

    Are you checked the clock line and data I/O line from the cpu to the eeprom?
    Very often a bad cap or some sort of bad pull up/down resistor can cos a messy data transfer or a bad timing so the data would be not transmitted to the eep
    correctly. Or several other things can also cos a bad content.

    At the end, could it be, does you got a sort of bad solder joint on the old eep legs, and when you changed it with a new one that solved your problem?

    But, however, it is an interesting repair article, nice to hear does here are peoples on the Earth who care and can save electronic devices from the junk and so the surrounding environment too like you.

    Keep up and my best regards.

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  5. beh

    January 17, 2019 at 10:45 am

    WELL DONE SURANGA.

    Likes(0)Dislikes(0)
  6. Hakan

    January 24, 2019 at 3:29 am

    Where did you find unfaulty eeprom content to reprogram?

    Likes(0)Dislikes(0)
  7. Emmanuel

    February 1, 2019 at 6:27 pm

    Hmmm! really educative and impactin, keep it on.

    Likes(0)Dislikes(0)

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