Dead X41 Tablet, mobo removed, bake? *PICS*

[ThinkBrad]

Hi guys, huge fan of the X41 tablet here. I've long maintained among my techie friends that it's the most underrated device of the mobile computing era, but that's a separate editorial.

I've been running mine fine on AC power for some time now, but recently delivered a gentle bump to its left side while it was sitting on my desk and the power cut off immediately. After testing the power cable to be fine, trying another 16V power supply, and discharging the capacitors according to the several sets of posted instructions, I'm still unable to get any signs of life - no lights, no beeps, nothing. I've made several similar attempts while sequentially removing components with no success.

I currently have the motherboard completely removed from the housing and tray and all components have been pulled as well. A new mobo is not very expensive but as I already have Windows XP and Microsoft Office authorized (and doubtful I can find their 7 year old documentation) I would prefer to rehab my unit because I'm not sure to what extent their authorizations are tied to the specific hardware ID. I have not been able to find a schematic for the motherboard but am otherwise able to diagnose any potential electrical faults. My tool kit stands at the ready if anyone can provide further guidance.

As an alternative, while I know its typically used to resolve graphics card issues, has anyone attempted to 'bake' an X41 motherboard? If all else fails, I may be willing to try ~7 minutes at 375* to see if the reseating of solder joints provides any improvement.

Does anyone have any advice for next steps or links to instructions for motherboard testing? I appreciate any guidance the community can provide. Thanks!

http://s14.postimage.org/tp1m7epbl/IMG_ ... 171345.jpg

Admin edit: Removed huge (220KB+) and blurry inline image

[twistero]

That picture is really small, can't see much from it.
Do you have a multimeter? You should first check whether the motherboard is getting any power at all. Locate the capacitor near the power jack (the largest of those tiny surface-mount components around the jack). When the AC adapter is plugged in, the voltage across that capacitor should be 16V or so. If it's not, then the power jack is broken, which is relatively easy to fix.

I had to repair the power jack on my own X41 tablet once. When I got it, the jack wasn't making proper contact, so it would lose power if I move it around too much, and sometimes it even made electrical arcs. Resoldering the center pin solved that issue.

[ThinkBrad]

Hey thanks so much twistero. I do have a multimeter, but looking at the board I realize I'm not sure what a capacitor looks like if it's not the cylindrical electrolytic type. Several hours now on Google and I still can't find a picture of a capacitor on a laptop mobo.

I did check the voltage at the rear pin of the DC jack, indicated by the red arrow below, and at the metal contacts on the component indicated by the yellow arrow, which might be the capacitor you're referring to. Both points gave a voltage that constantly jumped around between .5 and 1.0v (I held the black multimeter terminal to the VGA shield for ground, if that's ok). It seems like this indicates a faulty DC jack, correct?

I can see that the DC jack is connected by four through-board mounting legs, two on each side. The only other contact point I see is one pin going through the board on the rear of the jack. Everything seems tightly in place and wiggling the jack during the test process did not produce any change in behavior. I'm interested to know how the jack could be repaired, or the best place to source a new one. Thanks again for your help.

I apologize for the blurry photo - if any more are needed I'll dig out the digi cam and tripod next time.

Large size:
http://www.freeimagehosting.net/newuploads/jpsmj.jpg

Smaller:


Admin note: Allowing this image even though it's still over-sized (~120KB, when it should be <50KB). You might want to consider using macro or close-up setting on your camera. My opinion is that the yellow arrow is pointing to a 10A fuse, but then again, it's pretty blurry.

^^Admin, thanks. I resized it down to 640x480, 47kb. My apologies, the error was out of ignorance. Future image links will adhere to this standard. Thanks again for your consideration.

[RealBlackStuff]

Please be so kind and change that picture to a LINK (remove the [img]and[/img] tags before and after, it is WAY too big!
Thank you.
(go to that post and click the edit button at the right bottom of it)

[twistero]

The component at the yellow arrow should be the capacitor. If the voltage across the capacitor is only ~1V, the it indeed looks like a broken DC-in jack -- or possibly a broken AC adapter. Check the voltage across the adapter just in case.

All 4 side contacts on the DC-in jack should be ground, and only the center pin is the input voltage. Replacement power jacks can be bought on eBay.

[ThinkBrad]

Realblackstuff - thanks for the heads up, I linked to the full size and resized to 800x600 for inline presentation.

Twistero - I checked the AC adapter, steady 16.2v at the tip, and tried another from an R51 which showed 16.6v at the tip, so it looks like the problem is at the DC jack. Are the replacement jacks for the X41 compatible with the X41 tablet? The connections look identical. The only one specified for the X41 tablet on eBay is listed at $34 ($26+8), more than half the cost of a complete motherboard. Jacks listed for the X41 are ~$3.

X41 DC jack on eBay

X41 Tablet DC jack on eBay

I'll probably take it to a shop to do the labor, else I'd need to buy a desoldering pump, a new tip for my crusty iron, and thermal glue for replacing the cpu/gpu heat dissipators. It'll be quicker and easier to just pay the $20 for the job. Last question: is there anything else I should do to promote longevity while I've got everything taken apart? I wrote my PhD dissertation on this computer and plan to keep it in the closet forever for the occasional trip down memory lane. Is there anything you'd recommend I do to support that goal? Clean the thin layer of dust off the board? Larger heat spreader on cpu/gpu? I may choose to replace the 1GB RAM stick with a 2GB since I've learned of that trick on this forum, but can always do that later with relative ease. I appreciate any further advice, and I can't believe you haven't sold your X41 tablet yet, that's a great price on a fine piece of computing history! I'll try to spread the word. Thanks again!

[twistero]

The DC-in jack for X41 tablets and non-tablets are the same.
As for the preservation of historically-significant equipment, I don't really have any specific suggestions. ThinkPads are robust machines and should keep pretty well. Like all electronics, stay away from humidity, heat and sunlight, remove the rechargeable battery and store them about half-charged, etc etc.

[ThinkBrad]

Hey thanks so much for the help guys. I apologize for the sloppy pic links, I wasn't aware of the local conventions. I see to keep it under 50kb in the 'Rules of the Road'...is 640x480 the preferred resolution?

Regarding the DC jack, I received the replacement but I'm still waiting on a desoldering pump to do the job. Local shops wanted $45 and up for the solder work so I paid $5 for a desoldering pump and will be doing it myself.

A few other questions, though. I'll attempt to improve the cooling capacity by gluing the integrated heat spreader (IHS) from a spare pentium 4 between the CPU die and the heat sink assembly, according to this thread.

1) I've already tried cleaning the die with 91% isopropyl alcohol and a coffee filter. While I could see some grayish material coming off onto the filter, after several passes (not very aggressive) it looks like a good amount of old TIM remains on the die. Do I need to use Arcticlean or some other xylene-based cleaner to remove this? I'm not sure how hard I can rub the die to get it off but so far have erred on the side of too weak. Any advice? Here's a macro pic:



2) Same question regarding the contact side of the heat sink assembly. I removed the black-vinyl-and-aluminum sheet glued to the die-contact-side of the heat sink and tried cleaning the residue with the same 91% isopropyl alcohol but it looks like a good deal remains. Am I safe to sand this away with fine grit sandpaper, or would the resulting scuffs be even worse by reducing the contact surface area between the heat sink and IHS? Pic:



3) In reattaching the heat sink to the CPU and GPU, I've read that Arctic MX-4 is a preferred thermal glue for this application, and for the Pentium M processor specifically the glue manufacturer recommends the 'surface spread' method in which the small dot of thermal glue is spread across the die in an even layer using the edge of a clean credit card. Is this an advisable strategy among those of you in-the-know?

4) Finally, in reattaching the heat sink to the GPU, I notice that the GPU die mates to the heatsink via a small thermal pad, presumably due to a gap that would otherwise exist between the die and heatsink. It looks like the pad came off cleanly in one piece, and may not have been glued to the die at all. Should I put some thermal glue on the GPU die as well, to adhere to the thermal pad? Can I even reuse the existing thermal pad that's still attached to the heatsink or does it need to be replaced? Considering that the additional IHS between the CPU die and heatsink may increase the tolerance between the GPU die and thermal pad, should I also introduce an IHS between the GPU and heatsink, which would probably allow me to ditch the thermal pad altogether? I never noticed heat issues with the GPU so it would be more about consistency in the heatsink-processor die gap than actual cooling performance, but I wouldn't mind the preventative maintenance for the cost of a $5 scrap CPU. Basically I'm just not sure about the reattachment of the thermal pad - whether it can be reused, whether it needs to be glued to the die, and whether any additional gap will develop due to the IHS on the CPU. The OP of that linked cooling mod thread was nonchalant in his response to these questions, too dismissive to stake the fate of such a prized device on. Here are pics of the GPU die, heat sink, and thermal pad:







Ok one more quickie: 5) Should I leave those black vinyl coverings on the motherboard when reassembling? I found all kinds of mess stuck to the undersides of those - dust, lint, tobacco crumbs, there was even a small, dead fly stuck to the big section on the underside. I'm not sure if they are more protection or more of a liability.



I've done tons of research on these issues in general this week and have already learned a lot, but I'd really like to get device-specific confirmation this is ok before I start sanding into the heat sink or putting elbow grease into cleaning the CPU die. I really value my ThinkPad and therefore appreciate any helpful comments.

[RealBlackStuff]

If possible, replace the thermal pads with the same or just slightly thicker ones, to allow for compression of the old pads over time. Don't start sanding away, you'd make things only worse. Thermal paste should literally "fill the gaps".
I wouldn't use thermal glue, in case you may want to remove it later on.
To get the gunk of the CPU, you can use a razor blade or similar sharp (Xacto) knife, holding it almost flat, while 'scraping' the gunk off. Just don't scratch the surface, and don't use anything that does not have a straight edge.
Finish cleaning again with isopropyl alcohol.

[rkawakami]

The only thing I've ever used to clean off old thermal grease is a Q-tip dipped in isopropyl alcohol and a little bit of firm pressure during the back-and-forth rubbing. If you can find the 99% solution use that, otherwise stick to 91% (or better). The other 'missing' percentage is water so you probably shouldn't be using the diluted formulation; it will leave some residue when the alcohol evaporates. I'd also advise against scraping the top of the CPU with anything sharp as it's actually the bottom surface of the integrated circuit (silicon wafer). It could probably stand up to some small scratches inflicted upon it but why take a chance.

[ThinkBrad]

Thanks RealBlackStuff and rkawakami, it's an honor to be helped personally by the heavy hitters of the community. A few details remain, I've underlined the specific questions for clarity.

Rkawakami, thanks! The Q-tip gave me the leverage needed to remove the dried compound completely, which is good because I was hesitant to use a razorblade given my lack of a steady hand, and it saved me $10 on Arcticlean solvent too. Cleaning the black sticker residue off of the heatsink's mating surface has been less successful. I've gotten pretty much all of the sticker residue by scrubbing aggressively with alcohol and coffee filters, but the result doesn't seem like a very smooth finish, here's a pic:



…do you think that's ok, or should I give it a pass with a felt polishing wheel on the Dremel? It might help smooth it out with minimal abrasiveness, using one like this:





RealBlackStuff - my mistake in using the term "thermal glue", I'm leaning toward Arctic Cooling MX-4 (manufacturer's site), self-classified as a 'thermal compound', non-conductive, non-capacitive, and ranked in the top echelon in most of the rankings I've found…this is a good choice, right?


Regarding the GPU - the thermal pad measures approximately 12mm x 12mm but it's difficult to gauge the thickness…it's thin, like .5mm to .8mm. It's a bit frayed around the edges and soiled by my handling, so I'd like to replace it. After much searching, it seems like copper shims are a pretty highly recommended replacement in the overclocker community. For general reference, here are the sizes of several components, per my own measurements:

CPU die: 13mm x 6.5mm
Underside of square heatsink area for CPU contact: 25cm x 25cm
GPU die: 9.5mm x 9.5mm
Thermal pad between GPU and heatsink: 12mm x 12mm x .5mm - .8mm

I've ordered copper shims in several different sizes and plan to replace the GPU thermal pad with a (15mm x 15mm) or (20mm x 20mm) shim in .6mm thickness, which size will depend on how well I can work around the ridge in the heatsink opposite the monitor-side of the thermal pad. I also plan to bend the GPU side of the heatsink downward ever so slightly to compensate for any additional elevation of the heatsink above the CPU, as I've seen done on the German thinkpad forums. I believe the screws should hold everything snugly in place once reassembled. I'll try to snap some pics for future generations' reference. Please let me know if there's anything I'm neglecting to consider.

The final uncertainty is whether or not I should replace the black vinyl coverings on the motherboard. I assume they're necessary since the OEM engineers wouldn't include additional components at a cost if they didn't provide some benefit, but I can't help but think that they've done as much to keep junk trapped inside as they have to keep debris out, namely because of the small fly I found stuck to the tape on the inside. What do others think about this?


Sorry to require so much hand-holding, I've been researching the tar out of this for days on end now but it's still great reassurance to hear confirmation from the ThinkPad experts. Thanks again.

[RealBlackStuff]

That's a different product AND company from Arctic Silver 5 (AS5): http://www.arcticsilver.com/as5.htm
I am currently in the process of switching over from AS5 to AS CMQ2 (Céramique 2 Tri-Linear Ceramic Thermal Compound).
This comes in a 25g (!) tube for less than $8.- and seems to be 2-3 degrees better than AS5.
No idea why it is so cheap.

Do NOT use a Dremel, you WILL cause grooves in that surface, no matter how careful you work!

And do put the black stuff (!) back where it came from.
Or put Kapton tape in its place. Basically it's there to prevent accidental shorts.