Strange behaviour

[Rex]

Hi there,

I have posted before (many times!) regarding the BoD of my T20. Thought I had solved it but no!

Checking other posts, I see that a common T23 problem is some inductors coming loose; the solution seems to be to resolder them and check for other cold solder joints whilst the computer is in bits.

So I propose to check this part (doubt if it will solve my problem but one never knows) and check for cold joints.

But how do I check for cold solder joints? What exactly am I looking for?

Thanks for the advice.

Rex

[RealBlackStuff]

You'll find it in this thread and the other referred threads in there.
http://forum.thinkpads.com/viewtopic.php?t=39532

[rkawakami]

But how do I check for cold solder joints? What exactly am I looking for?

Cold solder joints are formed when the reflow process is not long enough or hot enough to properly melt the solder or some contamination is present. Generally speaking, you can identify them by their looks. A good joint will be smooth and shiny. A cold joint will appear cloudy and rough. However, due to the packaging techniques used on these laptops, many of the soldered connections will not be visible. The use of BGA (ball grid array) packages puts the connections under the chips where you cannot see or physically get to them.

I am, at this very moment, in the middle of looking at a T21 motherboard which is not completely powering up. It does not display the typical BoD problem as it throws the 1-3-3-1 error code when all of the memory is removed. It does not generate any video (LCD or external), nor does it seem to boot any media. What I'm looking for is any broken or loose connections and burnt parts. I've already removed the CPU and re-installed it thinking that it might have worked loose during shipping (the system was supposed to power up and display an error code). Failing to find anything like that, I'm going to re-assemble the system and hope that it works.

[Rex]

Thanks Ray,

Will have to disassemble now and have a poke around. Am not holding my breath but I really don't want to get rid of the Tp's as I really like them.

It will be some time before I get around to doing anything, but when I do and if the computer(s) come back to life, I will certainly post the good news.

Rex