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hector
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dim lcd problem being caused by the Mobility Readon 7500?

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Hie. I have an IBM thinkpad T42. Its been giving me the following problem for a while;

When I power it up at times it gives me one long beep and two short ones. In this instance the screen will be blank. After 15-20 seconds it turns off. Other times it boots normally but the screen is EXTREMELY dim. Without applying an external light source (a torch or something) you cannot see anything on the screen. According to the manual it appears I have a system board problem. I am not ready to let it go so I took it to a local repair guy who told me that this particular part (Mobility readon 7500 (m7-csp32 216q7cgbga13) needed to be soldered because it was loose. However, he says there is a chance that things could go either way i.e: he solders it and my T42 works as good as new or that will be the end of it and I would have to just buy another one. To show me that he knew what he was doing he applied pressure to the mobility readon part and booted up the t42 several times and indeed it started up without the beeping and dim screen. Is what I am being told really the case? Can I get this particular part replaced Mobility readon 7500??...or should I just get another system board or a new laptop altogether?? Please advise me on the best possible solution to my problem coz I don't know what's what anymore...

Edited by: oldturkey03 ( )

Thanks for all the advice. I think I'll try repair it on my own. Will let you know how it goes...

hector,

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ABCellars
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The IBM T42 with the ATI video chip is known for BGA failure of the video chip. I wouldn't suggest buying another board because of that. I would either attempt to repair it yourself or buy another system. If you fail at the repair then you really aren't out much and you will need a new system. If the Tech you took it too fails at it then you are out the repair cost and still will need a new system. If you decide to give repairing it a try here is a link to the service/hardware manual. It contains the teardown procedures and will show you where the video chip is. Here is a video of a T41 motherboard being reflowed. I did not see the guy put flux around the video chip in this video. But it is mentioned about flux flowing and flux activation. I would suggest using a "no clean flux" and putting it all around the chip on the motherboard, getting it as close as possible. One of the biggest causes of "back yard" reflowing not working and/or lasting is because of people not using flux to remove the contaminates on the BGA under the chip. If you decide to do the repair write down the timings this guy is suggesting as a guide. I would also suggest you get an IR thermometer to be sure your chip hits about 215*C but doesn't exceed 220*C. Good luck!

Edited by: ABCellars ( )

I noticed I did not address on of your questions. It would not be cost effective to replace the chip. You can buy a fully functioning T42 for less than what that would cost when you include it being installed.

ABCellars,

The 1 long and 2 short beeps is video circuit failure. You can verify that here: http://www.computerhope.com/beep.htm Your screen being dim is either the inverter board or backlight. There is no since in dealing with that problem if the issues with the video chip haven't been solved.

ABCellars,

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