Question about IBM ThinkVision L170 17" LCD Monitor

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Hellop i have exact same problem with the ibm 17", my is also the power invertor power circuit is dead, and the one of the 4 small IC that is @ back of the monitor, do u know what are they? or do u have one that is also borken but at least one of the IC still good? b/c i could use one

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  • allenpan Oct 28, 2008

    it is the power circuit, and is located at back of the power ckt, the ic i belive are either 8 pins or 10 pins, and marking= 4800 (or might be 4600) a03f12. one of the pin it on the ic is torched and i belive that is only problem, i dont have much experiance with DC to AC ckt, so i dont know what to test, can u advice me where is a proper vm test point?

    i will upload some photo next week, too much asg and labs to do

    thx for ur time greatly, fully appreshiated


  • allenpan Oct 28, 2008

    ahhh thx so mcuh, the "A04800 dual MOSFET " that is the one is torched, right now, none of the tube light up, i think is just due to this defected mosfet, do u knwo where can i pruchase those MOSFET...what is funny is we jsut covers MOSFET in class

  • Noel Rusnell
    Noel Rusnell May 11, 2010

    I do not have possession of the unit as the customer retrieved the parts (why...who knows?) without waiting for me to locate a replacement transformer. what are the markings on the four small IC's and on what section of which board are you working on--power supply or video processing? Are there visible indications of failure? what are the symptoms you are dealing with? do you have any voltages present on any of the circuits?



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The only numbers that come up for me are the 4800 as in an A04800 dual MOSFET array whose datasheet can be found here.

Remove the single retaining screw from each of the CCFL tube holders, remove the epoxy from the connectors and then disconnect the tube connectors and remove the 2 CCFL tube holders in plain sight (keeping the tubes themselves contained in the holders) from their places in LCD frame--so you can lay the holders in plain sight, then reconnect the tubes. Observe the tubes during power up...just be careful not to allow metal parts to make contact with other components or anywhere on the trace...if you observe one or more tubes dim or refusing to ingite, swap tube connections to isolate and determine whether the problem is faulty tube or power supply to the tube. If the issue is that no tubes light, check the pins of the BIT3105 Controller on the power supply circuit
hellop - 43c7d24.jpg
whose datasheet can be found here:

you should see similar values to these:

ϑ 7.43V on AVDD and PVDD
6.96V on CMP
1.25V on RTDLY
ϑ 7.4Von NOUT2, NOUT1, POUT1, and POUT2
1.52V on EA
213 Kω on PWMOUT
1.3V on CTPWM
.6V on DIMDC
3.9V on SST
0~.4mVon CLAMP

If you do not have INN voltage, check the the four 25v47µf caps connected to the BIT3105 CCFL controller (top-center of the board) and then the large electrolytic caps 10v1000µf cap (C551), 25v470µf cap (c661). visually check for domed tops or bulged sides. if these all check good, check the rectifier and regulator on the heatsink by the two large caps. then check the rest of teh electrolytic caps as before. continue working back in the circuit until you reach the Main A/C-D/C circuit.

Posted on Oct 28, 2008



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