Ibm Thinkpad t42p will not turn on

[aouate3]

oh and when the owner of this laptop was using it before it died, he was on youtube, charger connecter, then it just died, shut completely off, the laptop was on a table, the room temperature was at 80 degrees ferenhiet, and the computers cpu temp was 157 degrees ferenheit, he has a temp mointer applet in the xp toolbar.. he likes to keep his computer mointered, the owner of this laptop is a close fried of mine so i know him pretty well

[aouate3]

[quote="poshgeordie"]Get up off yer knees and start fault finding!!!


In my case the board is dead until you press on the board behind the audio connectors (the two big inductors), when it springs into life.
I then narrowed it down to not being a major chip (eg Southbridge) by having the board supported vertically with no stresses on it and gently squeezing both sides. Again the fault narrowed to something to do with the components in the same area you mention.




Hey Poshgeordie, have u tried replaceing the inductors, if u have to press them, it may mean some of the insulating wax has came off and there shorting, they do viberate at very high speeds i believe, too high to notice, hince where coil whine comes from....

[poshgeordie]

sounds like you had a similar upbringing to myself! it's a great way to learn about the workings of PC & laptops etc by reworking them as you have done to make "new" good ones.

I've not heard of inductors breaking down as you indicate, but I do know what you mean by the "singing" noise from them. I think they use enamelled wire and that enamelling is quite difficult to rub off, but it's possible I guess to have the turns vibrating slightly.
But I would certainly check the solder joints onto the pads and the ones on the component body are good too. Are you aware of the problems T2x's have with badly soldered inductors which actually fell off the board!

Try to use a logical approach when tracing faults - yeah I know that it's a lot easier with circuit diags which aren't available to us lesser mortals - but you can do quite a lot of tracing and it'll help build up your knowledge of these things, and you'll be able to start tracing bits of it out.

Re the battery charging, I'm fairly certain a forum member traced that part out and it's published somewhere within the T4x section - maybe try a search on "battery charging" or similar.

[aouate3]

ok, i will do some more fault finding a little later, dealing with my sisters bmw 330xi which she drove into a curb accidentally. and also a tree that fell on our roof, so i will try to get to it as soon as possible, also i wonder if there is a way to supply power to the board through the dock connector, maybe that would possibly get some change in its actions...

And yes the enamel is hard to wear off, but they can, rubbing causes a little abrasion in the enamel which rubbs against the enamel on the other wrap of coil, when the coil 's enamel is rubbed off enough to have the coil wraps un-insulated coil, the coil then shorts causing a different effect then what is normally produces, i have actually seen this on a lot of older desktop power supplys so i know it happens, it takes a while. but with them being so close to the heatsink, it aides in the problem

the inductors i may be able to replace, idk tho, if i can at least get them removed i can solder a wire to each of its solder pads on the board then solder the other end of that wire to its corresponding pad on the inductors...

[aouate3]

I'm going to look up a pinout for the dock connector... hey anyone with a thinkpad dock, can you charge your thinkpad through it or do you also need to have your thinkpad connected to the charger? i think you can charge it through the dock , im not sure, and the only one i know with a thinkpad dock is currently on vacation...


anyone know the pinout, i cant find one, there have been other people who asked about it on this forum but no replys were given, if someone has a dock and a multimeter, can you figure out which pins are for power, i think its the four pins that are by their self, but i dont know what there input requirements are, im thinking since the laptops charger is 16 volt, one of the pins should be 16 volts, im gonna use my multimeter and do a continuity test to find the ground or GND pins...

[aouate3]

This is what i have figured out so far from a continuity test

http://i754.photobucket.com/albums/xx18 ... ockpwr.jpg

the dc jack on the laptop, the positive lead does not directly go to the dock port, i know it passes through some fuses, but it also passes through something else, which i will try to find out right now...

[aouate3]

the two pins with the "?" are together, they are both basically just two pins with the trace connected to both of them, so that means it takes only one voltage... i will update my findings as i find

[aouate3]

ok, the positive from the dock connector leads to what looks like a MOSFET, with the numbering IOR434m...

now to make a quick connector for the dock, then to wait for the resposnse to one question, WHAT VOLTAGE DO I NEED? i dont want to fry this by pumping `16 volts into it if its not made for 16 volts, it doesnt seem like its fused, the ceramic white fuse is good, but my multimeter didnt pass the continuity test between the fuse and the positive pin, it seems to lead through some passive components and lead to something dealing with battery...not sure tho. maybe that fuse pdf of yours has some insight to it... going to it now

[aouate3]

fuse is for battery, fuse guide was very helpful. so the positive pin on the dock is not fused, that means on the dock is fused, odd place, not helpful if your laptop gets something conductive stuck there, ok, so that dock port looks like it has 3 MOSFETs, just like the front of the board, so that could mean it has its own "power delivery system",

Front MOSFETs

IOR436H
IOR433M
10R436H


Back MOSFETs

IOR434M
IOR436H
and a 8 legged chip labeled TPC8111 which google came back with
Field Effect Transistor Silicon P Channel MOS Type (U-MOS IV) Lithium Ion Battery Applications Notebook PC Applications Portable Equipment Applications

ok, so thats for battery, and after looking at the boards ultrabay, there is a IOR436H MOSFET

so those two are for battery

and the IOR434M is DEFINETLY for the dock's positive pin, since thats the only mosfet that seems to be for the dock, i am unsure if supplying power to the dockport would have any change on the laptops behavior, it would be a good test though, what voltage though?

after a little research, i found out that the docks power cable is 16 volts which is the same as the laptops charger, that 16 volts is probably used to power the port replicator on the dock and then 16 volts is passed to the laptop through the positive pin which leads to the IOR434m MOSFET which then leads to the parts requiring the power.... i will connect up the 16 volts as soon as poshgeordie can confirm my findings and thinks its ok to put 16 volts dc into the dockport positive pin... well i need to go fix a broken pipe caused by the fallen tree on our garage and pool pump, D.E. filter, timer, residental air pump, etc, this shall be fun -_-.....

[aouate3]

bump, anyone got any ideas? i am going to put 16 volts through the dock power pins, no one has replied, and i am anixious to find out if it will make a change in its behavior or maybe get the battery to charge.... if 16 volts is too high, i sure will find out and tell you guys for future reference, if it is too high of voltage, then i have a dead mosfet, but wait, arnt some mosfets auto reset? i read on some random russian site (had to use google translate to read it so it may have translated it wrong) and it said that a lot of MOSFETs are auto resetable, if i remembered the url for the site i would post it, but i dont remember


oh wow i just relaised i have posted a lot, i should of combined them into one post,

IF A ADMIN COULD COMBINE ALL OF MY LAST POSTS INTO ONE POST SEPERATED BY A "update" HEADER it would be very appreicated

[aouate3]

sounds like you had a similar upbringing to myself! it's a great way to learn about the workings of PC & laptops etc by reworking them as you have done to make "new" good ones.

I've not heard of inductors breaking down as you indicate, but I do know what you mean by the "singing" noise from them. I think they use enamelled wire and that enamelling is quite difficult to rub off, but it's possible I guess to have the turns vibrating slightly.
But I would certainly check the solder joints onto the pads and the ones on the component body are good too. Are you aware of the problems T2x's have with badly soldered inductors which actually fell off the board!

Try to use a logical approach when tracing faults - yeah I know that it's a lot easier with circuit diags which aren't available to us lesser mortals - but you can do quite a lot of tracing and it'll help build up your knowledge of these things, and you'll be able to start tracing bits of it out.

Re the battery charging, I'm fairly certain a forum member traced that part out and it's published somewhere within the T4x section - maybe try a search on "battery charging" or similar.

on that link there, it said a possible ticking noise near the cpu can be a symptom of a mis soldered inductor, before i connect up a adapter to the dock connector, im gonna check the inductors first... i will update you as soon as i find out the condition of the inductors

[aouate3]

inductors are fine, i think its that first MOSFET on the mains power jack

it goes, Power Jack - Fuse - Mosfet - Mosfet- Mosfet - smd part probably resistor - other side of motherboard

i think its the first MOSFET, it gets the hottest, its the first to get hot, and it seems logical...


ok, thats it, im gonna go connect up a 16 volt adapter to the dock connector and see if anything happens

[aouate3]

well it didnt work, 16 volts was the right voltage, all the mosfets on the front heated up, even the first one, also the one on the back heated up, i still think that there is a short somewhere, can someone get a multimeter and check there computer, tell me the resistance of there power jack, set your multimeter to the 20 setting, in theroy that may help tell if there is a short if there resistance is way different then mine, although other variable can account for different readings, including accuracy of the meter itself

[ajkula66]

You might find this thread (as well as some of the references in Ray's post) useful:

http://forum.thinkpads.com/viewtopic.ph ... 41+battery

Good luck.

[aouate3]

Hey Poshgeordie, how much would you charge to reball a northbride chip on a toshiba satellite laptop? just curious because i have a toshiba computer which is stone dead and i think its the north bridge chip, well its gonna take a trip into the oven, the normal "lazy" fixes, it fixed my mac, fixed my desktop mobo, fixed my ati graphics card and my nvidia, not to mention it fixed the controller board in my 19 inch lcd mointer.. so the oven is my friend just need to be EXTRA CAREFUL, not to move the board after its bake is complete, let it cool in the oven for a while

[poshgeordie]

Thanks for all that information - still digesting it!

We don't do work from the US coz the carriage costs make it prohibitively expensive.

It seems you've got yourself a nice little oven going there!

[aouate3]

YEP, the oven has proven to be a very useful tool if you know how to use it, its like a heat gun, just it covers more surface area...

[aouate3]

still working on it, freakin thinkpad, why wont you turn on -_-

[aouate3]

hey, one question, my friend is dealing with a alienware computer that the graphics card was lose, he had it in sleep mode and he didnt know, he pulled out the card then reinstalled it, the card is accessable from the bottom service panel, when he put it back in, he heard a crackle sound, like a spark, the computer wont boot, wont post, when he puts in a different graphics card, it boots fine, what happened to his card, all fuses check out good... what should he check next, he needs this working ASAP

THANK YOU O-MIGHTY KNOWLEDGEABLE COMMUNITY OF PEOPLE

[poshgeordie]

I'm not sure people here will be able to help since it's a forum for IBM laptops - maybe best to find another better forum?

Sounds like a short circuit somewhere to me - very hard to give any advise without actually looking at it....I'll get my crystal ball out!

[aouate3]

XD, Sorry, thought someone could give me some insight... a circuit short could be it, but what could if have blown, resistor, capicator, etc, which would have the highest likelyhood of blowing out?

[poshgeordie]

XD, Sorry, thought someone could give me some insight... a circuit short could be it, but what could if have blown, resistor, capicator, etc, which would have the highest likelyhood of blowing out?

Depending on the fault and its location it could be any type of component or even a track.

[aouate3]

Ok, Any Ideas about the thinkpad?

[ajkula66]

Well...

After you had yelled at me for pointing out the obvious, I decided to let this contemporary version of "Waiting For Godot" play for some time, but now I guess it's time for the final eye-opener...

At least three members with huge ThinkPad-related experience (Nick, RBS and myself) have pointed out that your patient is in need of a new planar. You've kept your course and have pretty much painted yourself in the corner. With that being said, here are the next steps for getting out of there:

a) For the sickly T42p: buy a motherboard and swap it. Sometimes the simplest solutions are the very best ones.

b) For your own exploration/education (which honestly shouldn't be pursued using other people's machines) : PM me your address and I'll send you a few T4x motherboards (for free) with various issues that you can play with and learn something in the process. All of them have a far higher likelihood of getting fixed than the one you're trying to repair now.

Good luck.

[aouate3]

Yea i was pretty determined to fix this motherboard, but i guess there really isnt a chance unless you were to strip the whole entire board of all of its smt components and solder new components on, which would be time consuming and not worth it...