I have two identical X31s that both had a very interesting problem- they would work fine until shutdown or put in sleep mode. After that wakeup would require complete removal of battery/AC adapters and then restart. Finally both are now refusing to boot at all. On power button press I see no LEDs/Fans etc.
I took both apart and measured voltages around MAX1631- both have Vl at5V, Vref at 0.
Shutdown is at 3.3 and both 5 and 3.3V enables are at 1.7V
I've swapped the chip on one, thinking it has internal damage and is loading the enable pins- same measurements.
I've also tried applying current limited 3.3V to enable pins- nothing changes
I see 5V VL and VCC3SW, but not much else. Any pointers what to look at? It appears that U3 is responsible for generating these control signals, and it does drive them to 3.3V, but by the time they get to the dc-dc chips, there is enough drop in series resistors to be as low as 1.7V.

All that info is way over my head ... have you tried the age-old attempt of flushing the capacitors? With AC and battery both disconnected, push in the power button and hold it down for a couple of seconds before releasing. Do this about 10 times. Then plug in the AC and attempt to power on.

-J

Well, it was the caps, indeed, but no type of flushing would've helped them. This one needed some more detective work with oscilloscope followed by some soldering iron magic
Tantalum output cap (330uF 6.3V) on the 3.3V line was old enough that it allowed a much higher ripple on that bus, triggering MAX1631 overvoltage protection. Swapped the cap for a brand new low ESR one and all is well now.

Well, I'm glad to hear you're back up and running. And still talking way over my head.

-J

How much AC ripple was present and do you know what capacitor (Cnn number) you swapped out?

I have exactly the same problem with my X31.

I would too be interested to know which capacitor you swapped out. A picture would be fantastic.

I'd love to know which cap was the culprit also as I'm learning to love my X31 and want to know all that I need to so that I can keep it running.

OK, here is the scoop:
I looked with the scope at the two outputs from MAX1631 (VR2) , at the output caps at the moment right after power is plugged in. I would see 5V come up nicely for about a few ms, then go off. The 3.3V rail would have a "beard" looking amount of ripple on it, so once I finally paid attention to that, I measured it reach as high as 3.6-3.7V, way over the 6% safety margin MAX1631 imposes. This was on both X31s I had.
I added a giant electrolytic cap across C646 (6.3V 330uF tantalum) and the system started. Then I went ahead and ordered low ESR caps from Digikey as a proper replacement. Both boards are up and running


3.3V line (C646): 399-4052-1-ND (Kemet T520D337M006ATE015)
While at it, I also swapped the 5V one as well, as they both are on whenever the laptop is plugged in:
C659 for 399-4045-1-ND (Kemet T520D227M010ATE018)

Pictures are at:
http://kuzyatech.com/fixing-an-ibm-thinkpad-x31
I marked the two caps in question. Note that the caps on the pictures are the replacement Kemet ones. The originals were dark colored. If anybody needs help with this repair- let me know, as I may be able to assist

Brilliant, thanks Reagle. I don't have a 'scope (or even a high-quality DMM) so you taking the time to trouble-shoot that and edify those of us who aren't able to is much appreciated. I've soldered in (Kemet) SM tants before, usually as replacements for small ali cans that have died. I was told that tants essentially last forever but obviously not quite.

With luck, and your information, my X31s will be running for many years yet. This sort of info is invaluable and represents the best of what a site like this can offer.

Thanks again.

P.S. If you come up with any more gems like this it'd be great if you can post them to this thread (I get notified) or ping me a PM. I fully intend my ThinkPads to last forever, or as close to it as practicable. Cheers,

I figured this might come handy for others. I myself almost gave up on this a few times, but eventually a bulb went up in my head after staring at the signals for a while

The only other known issues I've picked up on these is memory socket solder tends to get brittle with age, causing errors. Usually repaired by re-soldering the socket.

I'm pleased that it did. I have a mate who's an engineer by trade and a hobby electrical engineer. He's got a scope and is good with this stuff but problems like this usually take up so much time that he's not keen on isolating them on 'jobs' that are worth less than his hourly rate.

He's not a ThinkPad-head like me. He doesn't care about computers as long as they do the job.


Wicked! More good info, I can do re-flowing. I'm keeping all of this (and your pics, I hope that's OK?) in a folder in case it's needed in the future.

Cheers,

Reagle, thank you very very much for the information. Kudos to you. You are truly an invaluable asset to this community.

Hi Reagle,

I've not had any luck finding the capacitors that you mention locally (or anywhere that will ship to New Zealand). Will the following two Kemet part numbers do?

T495X337K006ATE100
(http://newzealand.rs-online.com/web/sea ... &R=2624743)

T491X227K010AT
(http://newzealand.rs-online.com/web/sea ... &R=5382717)

Thanks, they are available, in stock in NZ, in lots of ten. There are some that are lower ESR but they're either lots of one hundred and/or need to be imported.

Thanks,

Interesting info here. As you can see from this thread, I am currently battling a non-working X32, and the symptoms seem to be memory-related. How would I go about checking if it's a memory socket thing? The sockets do not seem to be physically broken, but the problems are present regardless which socket is used.

I'd be careful with the caps- the ones you list are all in a 100mOhm ESR range, the original ones were in 15-20mOhms if I recall correctly. Higher ESR means higher ripple on the output and possibly tripping the same overvoltage protection as the original old caps are doing now. I'd stick with T520 or T597 caps (or their equivalents from other vendors)
As far as memory sockets- I had to resolder their connections to the motherboard as that was cracking and not making good contacts

Thanks Reagle. I shall look again at the catalogue. I don't have much knowledge of these things, just an ever-growing pile of X31s that won't boot.

Cheers,

Ok, thanks again for the info and help. I've found a source and, for now, ordered three of each of the same ones you used. (NZ$35 delivered.) Hopefully they'll be here in about a week and, with luck I'll get to replacing the original ones.

Since I read of your successful fix I've invested quite a few dollars (at least relative to my income / the fine line I'm teetering along between paying the bills and bankruptcy) on buying a few second-hand X31s that were sold as being dead, no boot. I do hope that it turns out well, I really can't afford the alternative. I'm having to thin down my TP collection as it is. A very sad thing when most of them were bought in various states of decay and lovingly 'refurbished' and upgraded, not to sell on, more as a hobby / collection.

Best regards,

Last week I had a spare couple of hours so thought I would take a look at the motherboard. But try as I may I couldn't take the thing apart. I released all visible screws but the keyboard just won't come away. It seems to be held down at the middle and top edge of the keyboard but I can't see any screws. I also can't pull the cmos battery out either. Am I too old for this?

Heh! I doubt that you're too old.

The keyboard's not that hard but there's a trick to it. Remove the four screws underneath that have the little representation of a keyboard next to them. Then, with the battery removed you can reach into the battery recess and gently push the bottom middle of the keyboard with a finger-tip to get it started coming out.

I take it you've downloaded the HMM for the X3 series? If not you can get it here:

http://www.retrevo.com/support/Lenovo-X ... bh151/t/2/

Best of luck!

Thanks I managed to remove the keyboard and followed the maintenance manual to remove everything else. The motherboard is very compact and I am now lost as to which rectangular chips are the capacitors to replace. I've posted a picture of the board here http://www.flickr.com/photos/7300917@N0 ... hotostream and would appreciate a pointer when you have time.

Hi,
Check out the eighth post in this thread, by Reagle. It has links to pictures of both of the capacitors in question.

Cheers,

Hey all.

I've acquired an X31 myself in need of some attention. Completely dead, not a single light or sound when attempting to charge or power on.

Tried draining caps, removing stuff to no effect. Does it sound like the 3.3V cap has gone?

How easy is it to replace using a flat-tipped 40W iron?

Such a shame, it's a great little netbook and in really good cosmetic condition.

Cheers

EDIT: I also don't have an oscilloscope, would I be able to check the cap using a DMM?

That would be my bet based on experience. Try the two caps mentioned earlier, they're cheap enough.


How long is a piece of string? Sorry, that depends on your skills and the gods of luck. I've done it twice using similar equipment.


Eeeek!! It's not a netbook! It's a fully-fledged ultraportable notebook. "Netbooks" describe cheap little plasticy things that were made several years after the X31 that only had half the CPU power and were 'disposable'. Thank the gods that they're no longer 'en vogue'. They were an abomination with (generally) terrible screens and worse keyboards designed to fail just out of warranty.



No, at least not in place - and then if you removed it to test you need an expensive DMM to reliably measure a capacitor. Much cheaper to just replace. They're probably less than a dollar each, in my opinion the best bet is to just go ahead and replace them. After all, as long as you don't damage anything else you've got nothing to lose.

Best of luck.

My nearest component supplier doesn't stock the Kemet part nos you quoted but going by the capacitance, voltage and type I have found what seem to be equivalents. Would you be able to tell me if they are suitable:
http://australia.rs-online.com/web/p/products/6925810/
http://australia.rs-online.com/web/p/products/6925813/

I've been cleaning up my picasa account, so the pictures of the repair now live on my blog, together with the writeup.
http://kuzyatech.com/fixing-an-ibm-thinkpad-x31 I've updated the links in the original post as well.
If anybody needs more details on the repair, let me know and I'll add that.

Hi misfit,
I'm in WA and can order from RS Components too. Did you order and use those two part nos as I'd like to order the same and fix my X31 too?

Hi moviedude,
Yeah mate, they did the job.

Best of luck,

Oh I see that I have to order in lots of 10!

LOL, yeah, if you re-read my post you'll see that I said that.