LCD Timing

Discussion in 'General Electronics Chat' started by R!f@@, Mar 17, 2010.

  1. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Ahoy there mates,.... it's me again :)
    Don't think I am trying to increase my post by asking things. :cool:
    But don't mind if I do.

    I got this LCD a 19" HP wide ( beautiful baby ), but problem is, it has a faulty driver chip in the panel flex cable :(. So I stored the things I need and rest ended up in the scrap metal

    Now since I have moved, I gave away my old faithful 19" twin CRT's. Got no choice and now I have a measly 17" LCD.
    Expense has been over the roof and getting a new bigger monitor idea is falling back from time to time.

    And today a friend gave me a 19" LCD. Seems that it also was on it's way to the dump but luckily it found me.
    So checked it and it seems the VGA driver is creating a no signal and interference problem. Due to it being handled by a lot of wannabe repair techs here, the board is really in bad shape.

    But the good news is when I saw the LCD LVDS connector, it was Identical to my HP. BINGO !!!!!!!!!!! back to the works hop.

    So after a little cable and board swapping I managed to use the HP boards with this 19" LCD. It gave a beautiful display.

    One problem.
    HP is wide, where as this LCD is not, both is 19".
    So display is kind a funny, the task bar is a inch above and the top is at the bottom. :confused:.

    My diagnosis is the LCD timing in the EEPROM.
    Thought of copying the memory to HP but the normal LCD has one memory where as the HP has 3 of 'em.

    Does any of you have any idea on this type of thing, I never tried to copy the timing from one EEPROM to another and to make things worse I donno which one to over write.

    Any Ideas....Or is this one of those things that I have to do a research on.
     
  2. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    I see nobody have a clue.....
    Well !! let's see what I can do...again :).

    PS. I would really appreciate if who ever checks the post replies with something. If you donno just say so, then atleast I know how to post ideas in the near future, I am not going to judge any one, no body know's every thing. By this I know to finish working on something like this before hand and post it so others can have an idea who to contact if any thing arises like this.
    I can see the view count but I really donno who is viewing, and there are some members I really look up to make suggestions.
    :) of any sort
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
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    Ok, I have no clue. These are one of those posts I would expect you to reply to, Rifaa.

    There are no positioning variables to change in the menu?
     
  4. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    that's more like it. :cool:
    Na, nothing on the menu, I'm assembling it now, did a bit of metal work since it's mix of two LCD's, I need to change the layout of the inside metal frame work. Will post some pic's soon and then we'll discuss.

    From the pic below you can see the difference between the two panels
    [​IMG]


    From this picture it is clear that HP Display driver has DVI connections and audio inputs

    [​IMG]

    See the two panels connection are almost the same

    [​IMG]
     
    Last edited: Mar 18, 2010
  5. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    This picture shows the damages made by previous repair attempts
    and also note only one memory is used

    [​IMG]

    See the HP board. And the no. of memories used

    [​IMG]

    In order to use the monitor on a desk top I have to integrate the HP boards into the view sonic housing and it should be nice to look at atleast, so I cut the two metal frames from both the monitors and combined into one. Below is a picture of the complete assembly. The board mount frame is from the HP screw onto the view sonic panel frame.

    [​IMG]

    And also changes made to the back cover too

    [​IMG]

    After the assembly I tested the display but due to the long time the view sonic been stored carelessly, fungus had grown in side the panel

    [​IMG]

    [​IMG]

    Had a tough time taking the panel and the filters apart and clean them with glass cleaner but it was worth it.
     
  6. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    [​IMG]

    See the picture.
    That is final assembly, can't tell the difference, and the fungus cleaning gave a very clear display.

    As you can see the task bar is lifted and the top is also at he bottom and I cannot see the clock, which means it is scanning too much.
    The LVDS timing thinks it is driving a wide panel.

    The vertical and horizontal scan timing has to be adjusted.
    But the HP has no buttons. just a power button :confused:, or may be I think I threw away the switch PCB :(. Darn it !!!!!!!

    After a long time I get a good LCD free and I ended up with a bloody tilted image.
    And to think these things happen during the early days when I used to tackle CRT's, I never new LCD would do the same.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    Hang in there, Rifaa.

    Don't have a clue, because I'm here with all of my test equipment, and you are on the other side of the planet. You seem like a pretty determined fellow, so keep at it.

    And congratulations on progress thus far :)
     
  8. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Hola Rifaa,

    You links did not produce any pictures but a blank screen all the time.
     
  9. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Darn it.. :confused: hang on. I think I made a booboo in the UserCP setting

    Edited: Hola....Amigo ... andharey ...andharey .....:p
    I heared this in Mexicans fastest mouse cartoon :D. Am I saying this right?
     
    Last edited: Mar 18, 2010
  10. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Thanks.... do you think your test equipment can correct the timing? :confused:
     
  11. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Andaré is the word. The way you wrote it approaches how most of English speaking people will pronounce it.

    Another detail: Amigo to call someone, is used in the movies only. But when you hear somebody calling you like that, you respond. Why to deceive well-meaning foreigners? :)

    Since I work with foreigners 90% of my time, I know how the marvel of human communication works: sometimes very bad!!
     
  12. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    You might be wondering what I am up to now.

    Guess What?
    My fiddling found another unbelievable thing.
    I am continuing on this thread cause it is still the old HP Signal Driver board.

    A cousin brought an Acer X193W LCD. It had funny on /off no display problem. Luckily it came to me on the first failure.
    Checked and found the μC hiccuping..or it could be the LVDS Driver chip, either way I can't seem to find a replacement chip.

    After few Days

    Since I still have the 22" Acer LCD that I posted on a another thread I thought of checking it's supply for the unknown part no. tht my 22" supply had. Tough luck..the supply was different.

    I really dunno how it hit me to check the 22" HP's Signal board which I took out and assembled it into the view sonic 19" that I am currently using as a second Monitor.
    After opening it I compared the two. The picture below shows the 22" HP and 19 "Acer Signal Assy, both are wide.

    [​IMG]

    All my faults I found from both were correct and the Acer now gives a fine picture.

    But there is a tiny hiccup..the buttons are responding differently. It should since the EEPROM data is and brand is different. Now after power up I get an HP logo in an Acer Monitor.

    Nice no.......good for a laugh...!!!

    Me got another wide inch Monitor...:p

    [​IMG]

    What I really want to tell you guys is that although the chips are different, I see a similarity between the interconnects and the LVDS connector.
    So after checking the supply connection for proper voltage, I plugged in the HP board to the Acer an powered up. You can see it works.

    Seeing the similarity I think HP's like the rest Acer and Dell and all tht.

    And all these days I thought HP was unique, like Sony or Philips, u know.

    All made in china....:confused:
     
    Last edited: Dec 26, 2010
  13. nerdegutta

    Moderator

    Dec 15, 2009
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    Nice work, R!f@@. :)
     
  14. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    From analog point of view, setting up raster size is child's play. Once I reduced the size of 21" Sony PCB to a 14" identical CRT. Just like you said, have to add or reduce caps & inductor values.

    My main point is the vendor for control PCB for these, that is for HP. Acer, Dell or BenQ are the same company. They are not unique like Sony. So for Quality control point of view, it's not good, just business.
     
  15. retched

    AAC Fanatic!

    Dec 5, 2009
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    They are all competitors in the consumer market, Rifaa.

    The only way to keep prices competitive is to do that.

    It would be more expensive, thus shrinking profit margin, or increasing the end price.

    By using the same parts, the end result is JUST AS GOOD or BAD as the competing brands.
     
  16. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    I guess u are right....

    money..money..money..money..!!!
     
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