Question about AOC LM 720 17" Flat Panel LCD Monitor

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AOC LM700 17" LCD Screen switches to black and then comes back to normal. Power light never goes green but monitor works. LED is orange when off and in sleep mode, wakes correctly on getting input. Just flicks on a black screen after a while of being on and them flicks back to normal. Several posts are similar that point to an inverter issue but they all seem to get a green light. I have removed the inverter board and will redo the solder connections as has been suggested for somewhat similar isues. If the inverter board needs replacing is it an expensive part?

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  • markbose Feb 08, 2008

    Is that probably the issue with it? The green led not being displayed throws me off a bit from that conclusion.

  • markbose Feb 11, 2008

    We I took out the inverter and retouched the solder points and it did not help. The one factor that seems different that other posts is that the power LED never goes green when active it is out and when not connected or "sleeping" it is orange. I think that ties to the isue, any other ideas?

  • markbose Feb 27, 2008

    Sorry it took a while to get back to this. The inverter is a

    • Sampo REV.0

    • L0087

    • 79AL17-Z(or 2)-N

    • AD1H37-D/0151


  • markbose Feb 28, 2008

    Not a pc issue its a monitor issue

  • markbose Mar 11, 2008

    Computer or resolution does not matter. Problem exist on any computer including one it worked on for over a year. Still looking for a 90% answer since at $70 for a new inverter it is a marginally worthwhile repair as 17" have becme disposable. The inverter would seem to be the fix with the exception of the orange light. I have not seen that issue on any post.

  • Anonymous Mar 31, 2014

    After the "No Signal" comes up, then the monitor goes out as into a sleep mode.



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There is a known issue with these monitors, which cause symptoms including the display blacking out after warm-up, flickering, and a configuration error displayed on the osd. the cause is the mpu chip, which aoc now has a revised issue- although get it while you can [i've seen it on e-bay, too] because aoc is in the process of obsoleting this part. it's the small square chip WITHOUT the heat sink on it, located toward the top of the main [larger of the two] boards. fyi- the narrower board to the left [both boards have a shield over them] is the inverter board. that can and will cause a black screen if it's defective, but in most cases, the backlight won't come on at all.

Posted on Dec 07, 2008

  • david small
    david small Jan 26, 2009

    regarding the inverter board- it is available from aoc directly [although they are in the process of obsoleting this part] for forty-five dollars, plus shipping [about nine dollars, ups ground]. theire phone number is 888-662-9888. fyi- backlight and display problems [such as flickering, shutting down after warm-up, and error messages] are known to be caused by the mpu chip, which is also still available from aoc [also being obsoleted in the near future], at a cost of either 10 or 20 dollars, i forget which, and the shipping cost- but if you order both items at the same time, there's only the one shipping charge. this chip has been advertised on e-bay from 59 dollars up to like 80 dollars. - so, i would suggest ordering one from the mfg. while you still can! good luck


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According to LCDParts, an inverter for an AOC LM700 would cost $69.99. Specs (with picture) are available here.

Perhaps you can do a Google for lesser priced versions.

Good luck and kind regards.

Posted on Feb 08, 2008

  • 1 more comment 
  • Louie  Role
    Louie Role Feb 08, 2008

    Hi again,

    Based on your description, all points to a cold solder problem. But then again you can't verify till the unit is opened up. In some instances, it could possibly be corroded connectors of the CCF Lamps or blistered capacitors.

  • Louie  Role
    Louie Role Feb 11, 2008


    Copy your last post. That was the easy part. For info only, pls confirm whether the inverter was 79AL17-1-S or the 79A-L17-3-S. The reason for the query is that there are 2 versions of this monitor, either manufactured by CHI-MEI or by Hyundai.

    I am considering the not going to green but stays orange. Will let you know when you post back inverter numbers.


  • Louie  Role
    Louie Role Feb 28, 2008

    Copy your last post.

    A shot in the dark for the orange light: assuming everything in the monitor is connected right (including inverter), have you tried running the PC in a lower resolution (display properties)? and/or lowering the screen refresh rates? or running another monitor to the PC to verify whether it is the video/PC or really the LCD monitor?

    Had me thinking on the orange a week or 2 back.



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