T40 Will Not Turn On At All

Message

daveycmc · #1 Post by **daveycmc** » Tue Mar 22, 2011 5:47 am

Hi there,

I have had problems with my T40 before, but as it has served me well for 6 years now, so I can't complain too much.

Recently, I had noticed that when unplugged from the AC mains, the battery would last less than 60 seconds before I started getting the low battery beeping noise. I made a note to order a new battery.

Before I got round to doing that, the unit just died. Turned it off at night a few weeks ago, and it has refused to turn on since.

When I say it wont turn on, it wont even start up at all (no motherboard activity, no fan noise, completely dead).

When the AC is plugged in, the little green status indicator on top of the laptop lights up to say it is getting juice.

However, when I then press the 'on' button, the green indicator goes out, and nothing (I mean nothing) happens. I have to then unplug the AC, take out the battery, and then re-house it and plug the AC back in to get the green light on again. It wont come back on otherwise.

'Battery' I thought, so ordered a new one. Same problem even with new battery.

I started reading over the net about similar problems, but they all seem to be where the laptop actually hums into life (flashing lights, fan noise etc) but wont 'boot'. My problem doesnt even get that far, and I have had no luck searching for symptoms exactly like mine.

FTR, I have tried the 'hold the power button in for two minutes/press the power button in and out for two minutes/etc' type fixes which seem to have worked for others, but alas it does not work for me.

Can anyone shed any light on what the fault may be?

Thanks in anticipation.

lukee · #2 Post by **lukee** » Tue Mar 22, 2011 5:58 am

Look for fuse locations on motherboard. This could be a one of the possible causes. Search forum for T4x fuse locations.

daveycmc · #3 Post by **daveycmc** » Tue Mar 22, 2011 7:19 am

I have printed off the fuse guide from here, and will have a look tonight.

I have also seen reference to the CMOS (or is it BIOS?) needing to be removed and the power button depressed for a couple of minutes to repair this fault.

Is it easy enough to remove the CMOS?

Ta.

#4 Post by **RealBlackStuff** » Tue Mar 22, 2011 8:47 am

Remove the keyboard and palm rest, then use small pliers/tweezers/your fingers to pull out/up the CMOS connector.

daveycmc · #5 Post by **daveycmc** » Tue Mar 22, 2011 9:02 am

RealBlackStuff wrote:Remove the keyboard and palm rest, then use small pliers/tweezers/your fingers to pull out/up the CMOS connector.

Thanks for the info.

Is there a diagram handy that shows me where the CMOS connector is?

#6 Post by **RealBlackStuff** » Tue Mar 22, 2011 9:28 am

When you remove the palmrest, you can't miss the CMOS battery (big round yellow thingie left of the hard disk cage).
Follow the wires.

daveycmc · #7 Post by **daveycmc** » Tue Mar 22, 2011 9:39 am

RealBlackStuff wrote:When you remove the palmrest, you can't miss the CMOS battery (big round yellow thingie left of the hard disk cage).
Follow the wires.

Just watched the video on Lenovo website.

Pretty straight forward to remove.

So, remove it, leave out for a while (?), then replace and see if laptop will run?

sarbin · #8 Post by **sarbin** » Tue Mar 22, 2011 10:45 am

welcome to the thinkpad forums.

the downloadable hardware maintenance manual located here:
http://www-307.ibm.com/pc/support/site. ... MIGR-46464
may also serve you well in your troubleshooting and repair efforts.

hth.

kaede · #9 Post by **kaede** » Tue Mar 22, 2011 9:18 pm

cmos is the one located near the internal speaker. the only yellow colour i guess?

poshgeordie · #10 Post by **poshgeordie** » Wed Mar 23, 2011 2:53 am

Yes it's the yellow disc.

For fuses and stripping & builiding up etc download the How To's doc in my sig, and you'll find a list of downloadable docs.

daveycmc · #11 Post by **daveycmc** » Wed Mar 23, 2011 8:55 am

Removed the CMOS battery last night, then held the power button in for a couple of minutes to degauss (?).

Replaced it, put the laptop back together again, put the main battery and AC feed in as well.

Same problem.

I take it the next step is to check the fuses as detailed in poshgeordie's how-to documents?

What are the likelihoods that it is one of these fuses that is the cause of the problem? Is it a common thing for these to go? How hard is it to purchase and physically replace these fuses? Are they soldered into position?

Thanks.

poshgeordie · #12 Post by **poshgeordie** » Wed Mar 23, 2011 9:48 am

Fuses do blow so it's a possibility. Before checking remove the AC Adapter and battery - remove the CMOS battery as well if you want.

Use a multimeter set to ohms to check the the continuity (conduction) through each fuse. If you don't know what this means or how to do it then I suggest you don't.

Most people solder the fuse on top of the existing one as the easiest way. Fuses can be bought in the UK via the shops listed in the Fuses doc.

Alternatively we do Thinkpad repairs in UK. If I can help please send me an email to nick@reflowrepairs.com or via PM with your email address, and I'll send you our details.

daveycmc · #13 Post by **daveycmc** » Wed Mar 23, 2011 10:25 am

poshgeordie wrote:Fuses do blow so it's a possibility. Before checking remove the AC Adapter and battery - remove the CMOS battery as well if you want.

Use a multimeter set to ohms to check the the continuity (conduction) through each fuse. If you don't know what this means or how to do it then I suggest you don't.

Most people solder the fuse on top of the existing one as the easiest way. Fuses can be bought in the UK via the shops listed in the Fuses doc.

Alternatively we do Thinkpad repairs in UK. If I can help please send me an email to nick@reflowrepairs.com or via PM with your email address, and I'll send you our details.

Thanks mate.

I am an electrical engineer to trade, so weilding a multimeter is no problem.

Soldering is another story. I can do it, but it haven't done so since college.

daveycmc · #14 Post by **daveycmc** » Fri Mar 25, 2011 11:26 am

Right.

Checked ALL of the fuses with my multimeter; they are all in tact.

I know the board is getting power, as I checked across the DC power block with my multimeter.

Given all of this (coupled with the above) is there anything else I can try, or is my laptop beyond repair? (i.e. new MB, which is pretty much cost-prohibitive).

Thanks.

#15 Post by **RealBlackStuff** » Fri Mar 25, 2011 12:30 pm

Have you tried another AC adapter? Those are not infallible...

poshgeordie · #16 Post by **poshgeordie** » Fri Mar 25, 2011 1:33 pm

You've checked everything you can so the problem is elsewhere.

It's not unknown for this to be caused by an unsoldered GPU or Southbridge but it could just as easily be something else.

For more info on repairing these chip in UK, see my sig / read this thread.

I would normally offer you a refurb'd board but I don't have any at the moment - but should in the near future.