10-22-2009 05:11 PM
OK, so first let me tell you what is not causing this problem, charger, pcmcia, diskdrive, display, power port, ram, processor, battery
so here is my problem, my ibm thinkpad t42p will not power on. i have repaired over 100 ibm thinkpad computers ranging from the i series to the T61, my current laptop (my t42p) is seeming to be experinceing a power problem, i have probed the motherboard for damage and there is no damage, i am 15, pretty young to know a lot about computers, but i was taught at a young age, i have checked the motherboard at a couple of different spots and voltage is getting there, there is no voltage, however, coming from the keyboard port on the motherboard, there should be a little voltage coming from it because there is the power button on the keyboard, the problem happened today about 3 hours ago, i had it in my laptop bag, it was on and i had it plugged in to charge. i also had my cellphone connected to it through usb, i noticed there was a problem when my phone beeped indicating the charger had been dissconnected. i had thought that it had gone into sleep mode, then i reliazed i had it set not to go into sleep mode. i took the ibm thinkpad out of my bag to find that the power indicater light was off, the computer was hot and the charge light wasnt on. i didnt have the bag completly closed and i had the back side of the laptop faceing the opening to keep airflow. i wasnt blocking the vents and it stays relativly cool. i have noticed that it had started making a high pitched noise near the power port. i thought it may have been the modem, i removed it, the noise still remained, the noise only occurs when the charger is plugged in, right now i have the laptop sitting on my desk, it is my only laptop at the moment and i have resorted to using my phone to post this problem, i have a lot of school work on it and i dont want to have to get a new laptop, have a extra motherboard. but the lcd inverter circuitry on the motherboard itself was dead. could someone tell me what the problem could be, how to fix it, and how to prevent it, i have a soldering iron, heat gun, solder, wire, a spare motherboard to use for parts . please, someone, i need THIS laptop to work
10-22-2009 05:30 PM
You could try to reflow your GPU, Northbridge and Southbridge, but i think there is more than one point of failure. You most likely would need a new motherboard.
10-22-2009 06:19 PM
well... i used my heatgun and reflowed the solder on the gpu, southbridge or northbridge, still wont work, and there is only 0.02 volts going to the battery, i am thinking that something that has died in the region shown in red on the image here http://supernerdyking.com/laptop.aspx. i am thinking the high pitched noise was a sign of a part in that area failing, the high pitched noise was coming from that area, what i need is someone to tell me which of the parts could of died, because like i said, i have a motherboard to use parts from, and i am only 15, and i dont have a job, so i couldnt buy a new motherboard,. maybe some schematics or something, any help is appreicated
10-22-2009 06:45 PM
You can only guess what parts are in those area, as IBM never released a blueprint of their motherboard design.
10-22-2009 07:23 PM
There is no such thing as "the main transistor"...not on an IBM/Lenovo planar.
Chances are, after your quick reflow, that board has to be discarded.
10-23-2009 09:01 AM
OK...well I took it up to a local shop and they took a look at it, they said that something on the board that has blown, they said that is why no power is being sent to the keyboard port, they said that the blown part IS somewhere in this diagram http://supernerdyking.com/laptop.aspx , they said that its easily fixed and its pretty common from power surges, they said it would cost $100 (us), I have a spare motherboard I could use for components to fix the IBM thinkpad t42p, they also tried reflowing it and letting it cool overnight. It still has the same problem, they wouldn't, however, tell me where the blown component is, that's where I need help, someone must know what could be wrong
10-23-2009 05:24 PM
only the IBM electrical engineers know, but they are bounded by whatever clause about design secrecy.
10-24-2009 04:54 PM
my school has a ton of ibm thinkpads, would it be wise on asking them if they have one i could use the motherboard out of or should i just get a new laptop