Please help in diagnosing TP 390X boot problem

Older ThinkPads.. from the 600, the 7xx, the iSeries, 300, 500, the Transnote and, of course, the 701
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catback
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Location: Dallas TX

Please help in diagnosing TP 390X boot problem

#1 Post by catback » Tue Aug 11, 2009 4:13 pm

Hi,

I'm trying to figure out a booting problem I'm having with a TP 390X. When the laptop is started, the following occurs:

-standard beep
-the display turns on. it looks like only the backlight comes on. there is no image of any kind that is displayed.
-the floppy drive is cycled on
-the hard drive is accessed for about 10 seconds and then it stops

After this, the laptop will remain on with the backlight on but the hard drive is not accessed. Nothing else afterwards.

Any suggestions on where I can start? I've read a few posts about the CMOS battery but I'm not sure if this would be a symptom of a bad battery.

Any help would be appreciated.

Thanks.

SMA
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Re: Please help in diagnosing TP 390X boot problem

#2 Post by SMA » Tue Aug 11, 2009 4:27 pm

Try attaching an external monitor.

catback
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Posts: 64
Joined: Thu Jan 17, 2008 1:06 am
Location: Dallas TX

Re: Please help in diagnosing TP 390X boot problem

#3 Post by catback » Wed Aug 12, 2009 11:35 am

An update to this. The laptop boots up and works fine. The only issue is the LCD. The backlight works and it provides adequate light. Just there is no image on the screen. When connected to an external monitor, the external display show the images properly.

Would this be an inverter problem or motherboard problem?

SMA
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Posts: 274
Joined: Fri Jun 29, 2007 3:48 pm
Location: Copenhagen, Denmark

Re: Please help in diagnosing TP 390X boot problem

#4 Post by SMA » Wed Aug 12, 2009 12:36 pm

About the only thing that the inverter does, is to generate the voltage that drives the backlight. And the backlight does work,
so that rules out the inverter.

It can be the LCD panel, the LCD cable or the motherboard.

Sometimes, with old electronics, it helps to take things apart and then assembling them again. That is, re-seating all the connections.
Also you can look for visible cracks in the LCD panel and check the fuses on the motherboard.

Besides from that, I cannot think of anything else to try, except from starting to replace the mentioned parts, one by one, until it works.

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