Help!! My IBM T42 wont power on.

[mongdu]

Hello everyone,

My IBM T42 one day just won't power on. I was using it, turned it off, after a few hours, I hit the power button and nothing happened. I search this forum and took it apart, did the individual part test and fuse check, etc... I discovered something not mentioned before on this forum (sorry but I haven't read the entire forum word for word). Anyway, The laptop actually would Power ON each and everytime I plug the keyboard back onto the motherboard without pushing the power button, it even show the startup "IBM" screen, but after only for a few seconds the laptop then turned off. Pushing the power button with the keyboard already plugged in and nothing happened. The laptop only seems to power on when I unplug keyboard and then plug it back on again and instantly the laptop would power up but turned off after a few seconds.

I have tested every parts on another IBM laptop. the only thing I have not done is swap out the motherboard (yes I even done the solder reflow on the GPU). So the only conclusion I could think of is the motherboard is bad or that keyboard is bad...So Does anyone knows what the problem might be or have a similar symptoms?

Update -- I did the reflow about 6 months ago, and everything worked good up till now, also, this laptop has been use primarily as a desktop, so there were no moment, it just died...with the AC adapter plug in, it still charging the battery...however, if I remove the battery, and unplug the keyboard and then re-plug it, it does NOT power up. But it will Power up with Battery by unplug and plug back the keyboard.

[billp117]

It's broke and needs to go to the shop!!!

All kidding aside, you are close to resolving the problem. You certainly put a lot of effort into this unit. If it were me I would get another motherboard. But perhaps you could check a few other items. The power jack may be intermittant, you did not say if this works with the battery in or out, and was it the same or worse after the reflow.

Do you have a dock? You can always use the "ON" button on the dock to see if it will turn on. I would not trust the reflow as your solution...that seems to be rather hit or miss.

There have been some good buys on eBay for motherboards. In fact some of us have done the TR451 conversion by installing an R51 Intel motherboard into a T42 series. They work very well and there are new one's for sale on eBay. http://cgi.ebay.com/39t5510-FRU-IBM-R51 ... 2eadf517f4

Hope that helps. I am sure others will give you some input.

[RealBlackStuff]

What about trying another keyboard on your laptop, that seems to be the culprit.

[poshgeordie]

Mmm I've seen this from time to time. I would suspect that the Southbridge chip has become unsoldered.

You've now got three different answers, so I suggest you put them all in a hat and the one you pull out will be the correct one (so long as it's mine!!)