T23 won't start - steady fan, can hear CD spin up

[kevinjatkins]

Hi,

I've searched these forums and others have had similar problems but the fixes (eg, resoldering inductors) haven't worked.

The problem specific to this machine also varies according to whether the battery is installed or not.

With no battery installed, when the power button is pressed, the lights come on then all except the 'power' LED extinguish and nothing else happens. The CPU fan runs, and if a CD drive is fitted, I can hear the disc briefly spin up, but nothing appears on the screen, nor from the VGA out connector (even if I toggle the display via the keyboard). Also, there's no backlight, and the 'Thinklight' doesn't toggle on or off. The chipset, including processor, becomes warm which would indicate good power and the video chip also warms up. I've measured a few voltages - the 5V rail seems OK, as does 3V (haven't measured CPU core voltage though)....

If a battery is installed, the symptoms are similar, except that when the power button is pressed, all the lights come on and stay on, with the exception of the battery charge light, which remains off. It's then not possible to power down by pressing / holding the power button - I have to remove the battery to turn off. This would suggest a problem with the charging circuit, but I don't know if this would have anything to do with the other issue.

Anyway, if anybody has any suggestions, I'd be very grateful - I'm currently using a T30, but I really prefer the T23 because it's slightly slimmer and lighter, somehow 'feels' more robust, and the performance penalty is negligable IMHO.

Thanks,

Kevin.

[rkawakami]

Welcome to thinkpads.com!

I've had some experience with T23 problems but not quite like the differences you describe about running with or without the battery installed. If you haven't already tried this, remove all hardware (memory, hard drive, MiniPCI card, ethernet card, Ultrabay, PCMCIA card(s), battery, etc.) and then boot the system with only the AC adapter. You should at least get the 1-3-3-1 "memory failure" beep code. If the system is not even doing that, then some investigation into the motherboard is in order. Could have a problem with the CPU, or there might be a power supply issue, or there could simply be a broken connection somewhere (typically a badly formed solder joint when talking about T23s). You may even have a "missing" component; such as an inductor which has completely fallen off the board and then exited the system, assuming that it came to you in its current condition. If, however, the system has been working for you and then suddenly developed this issue, then all of the parts are probably still there.

I've found that one of the techniques that you can use to troubleshoot T23 systems is to apply some torque to the front left corner of the base. Flexing that corner up and down with respect to the rest of the base can sometimes temporarily "fix" a problem. If this works, that points to a bad solder joint somewhere (good luck finding it ). I was lucky once and got a dead T23 system to boot while holding on to front left corner. It turned out that there was a crystal that had tiny cracks in the solder on two legs.

Battery charging issues with the T23 can also be affected/caused by a loose inductor. That one is on top of the motherboard, just below the S3 video chip. This thread:

http://forum.thinkpads.com/viewtopic.php?t=37956

has a link to some scans I took. If you look at the "top side w/legend" link, that battery inductor is located at G6. The other three inductors which usually cause problems are at A1/A2 on top (in my scan it's missing since I needed it to fix another board), and at C9 and E8 on the bottom. The crystal that was detached is on top at J6/J7 and is labeled "Y6" on the motherboard.

Besides these components, look carefully at each IC both on top and bottom of the motherboard. You might find one which has definite burn marks (or holes!) which is a good indication that it's no longer functional.

[kevinjatkins]

Hi,

Many thanks for the quick reply and kind welcome.

Yes it's proving to be a stubborn one this is... With everything removed, including memory, I'm not even getting the beep code, so something is definitely amiss.. I've had a look at your excellent topic and scans of the top and bottom sides of the board and all the inductors are present. I've resoldered all of them, still no joy, and I've just had a go at flexing the board and it's still dead.

I'm wondering if the CPU might be faulty - I've tried reseating it. But do CPU's really die? And would a dead CPU get warm, like the one on this board does - that tends to suggest that it's running to me. Well, I should be able to lay my hands on a known-good CPU in the next couple of days, so I'm going to try a substitution. I'll keep you posted with progress.

Many thanks,

Kevin.

[rkawakami]

Yes it can be possible that the CPU is faulty and yet still get warm. Warmth equates to drawing power but doesn't necessarily mean that it's working 100%. There still could be a power-related issue from one or more of the components on the motherboard, but the CPU is the last easily changeable piece of hardware you can swap out. A word of warning however: there is a very slight chance that whatever went wrong with the motherboard, it caused damage to your existing CPU. A replacement could theoretically be damaged in the same way.

[kevinjatkins]

OK, so the CPU could be faulty - at least it might be worth eliminating before digging deeper. I take your point about possible damage... I think I might pop the existing CPU out and measure core voltage supplies etc before I try installing the good processor..

And once (if!) I get this one fixed, I've got a pile of four T20's to work through - I bought the lot for £21 off Fleabay, so I can't really complain! Be nice to get at least one working though....

[kevinjatkins]

OK, I've ruled out the CPU. I put the suspect CPU into a known-working T23 and it booted fine; I then put the known-good CPU from the working machine into the suspect motherboard... same problem.

I believe there is a power management IC on these that can sometimes go wrong. Is that correct? I'm beginning to think that might be the issue...

[rkawakami]

There's several power management ICs on the T23 motherboard. If you look back at the post I linked to earlier, I have listed a few of the power controller ICs that I've found. Most are made by Maxim, but there's one by Toshiba. Note also that the problem could be in any one of the other components that are on the board. I had one MOSFET turn into an LED just before a plume of smoke arose out of it, but that took out the whole board.

[lmiklosy]

I too have a T23 type 2647-RU3 with a blank video screen and no external video. Here is a list of remedies I tried on the system board with no improvement to the symptoms:

1. re-solder on all inductors top and bottom
2. re- solder on crystals at Y1, Y4, Y6
3. A-B swap-outs of processor, cmos battery, memory
4. boot with minimal peripherals no ethernet, drives
5. finger pressure on graphic chip and other locations to ground backplane

Lifting the left bottom corner and pressing F1 will sometimes give me a splash screen on an external monitor and POST will run till the CRC check (error code 175), the machine will not enter the BIOS setup screen.

Lifting a corner of this laptop was successful months earlier, but since then the system seemed to degrade further. Can anybody (rkawakami, realblackstuff, zyzx) offer more components I can try re-solder (fuses, crystals)

One last clue, the inductor at G6 Top in Ray's diagram seems to run pretty hot as does the Savage graphics chip, does that seem normal?

Thanks for your suggestions.

[rkawakami]

Last one, first.. The G6 inductor controls the battery charging. I would guess that it will run a little warm (never tried feeling one when powered up and a battery installed).

Double-check that you have removed the MiniPCI (modem/wireless) card as that can also induce a power problem if defective.

Your observation that twisting the corner of the system seemed to allow the system to proceed (slightly) further along the boot process seems to say that there's a loose component somewhere on the motherboard. However the 0175 error code might indicate a more severe problem. So far the only T23 that I had which exhibited that type of problem was because of a badly soldered crystal (the long one at the J5/J6 map location).

Also, if you haven't tried this already, remove all memory modules and see if you at least get the 1-3-3-1 beep code. If you do and it doesn't seem like you have to do anything special to the laptop (like lift or twist the corner), then try a single PC133 module that's known to be good (tested in another laptop if possible). Install only ONE module and see if the system boots. If it doesn't, move the module to the opposite memory slot and boot again. You may have a problem with a bad memory slot or defective memory. Although getting video out the external port (at times), probably means that the memory is okay but it's a worthwhile diagnostic to run.

[lmiklosy]

Thanks Ray,

Removed all memory, the MiniPci (previously removed) even the keyboard and tried to boot. Still no video signal and no beep code from either the missing memory or missing keyboard. Replaced the keyboard and repeated with same result. Replaced one stick memory with same result.

Yes lifting the corner would suggest a loose component on the board or even the memory slots. I'm typing on a T30 with a broken memory slot that I repaired with a soldering iron, so I'm familiar with the memory slot failures on these T30's. But looking at the T23 slots I don't find any cracks or oxidation. The T23 has much better solder joints than the T30 and I don't suspect them like I do on the T30.

General comment: all these repairs are handyman variety that could be done by a good technician with lots of patience and good visual inspection skills. What this forum needs is some good diagnostic procedures for a semi-dead motherboard like mine. We need a way to probe a system board from the serial interface or better a USB. Anyone working on this outside Lenovo? <removed comment about password hacking tool per forum rules> We need tools like his!

Another comment: Can anyone on this forum offer the failure rate data of components on these boards? How many inductors fail, how many clocks, how many controllers and how many fuses? If we had statistical data, we would know where to direct suspicion first and where to look last. Would IBM/Lenovo offer this data to the forum?

Cheers,
Les

Admin edit: Removed a sentence pertaining to a password hack. See forum Compulsory Rules #5: http://forum.thinkpads.com/viewtopic.php?f=16&t=14339

[rkawakami]

I'm sure it would be next to impossible to get any reliability data out of IBM/Lenovo concerning systemboard related failures. Trying to mine the data here in the forums would also tend to skew the results towards the high side since people usually don't search out and post in these types of forums when there's nothing wrong with their system.

That said, I'd say that the most typical problem for the T23 (based upon the 60 or so systems that have passed through my work bench) would be the loose inductors, followed by seemingly random component disconnects from the motherboard; assumed cause of failure would be flexing of the system, combined with the use of brittle lead-free solder or poor application of said solder during manufacturing. Yes, I've seen blown fuses, melted MOSFETs, defective MiniPCI cards and bad memory slots on T23s so those contribute to the failures as well. However, since my main eBay prowling has to do with parts and repair systems, my own data is hopelessly flawed .

[lmiklosy]

If the board failures you saw are mostly surface mounted parts, I find that very encouraging since those are the board failures we can repair with basic tools. My anguish is with boards where the ball-grid array or the IC is suspect and I have no way of testing them. That is when I have to make a decision to scrap the board. Since your experience shows more conventional parts are suspect, that suggests I keep looking for the right one.

Maybe I have an oxidation problem? Think I'll try pulling out the system board again and tracing the inductor leads to a junction where I can take impedance measurements. I'll let you know what I find.

TX, Les

[rkawakami]

Well, basically all of the components on the T23 motherboard are surface mounted. There's very few through-hole parts. But you are correct in saying that it's hard, if not impossible with limited tools, to test individual ICs or see if one of the BGA solder bonds under the S3 video chip is broken. There have been some other power-related problems with T23 systems reported here that did not resolve to loose inductors. Those could very well be caused by one of the Analog Devices, Maxim or Toshiba power controller chips going south, as well as any of the passive components being disconnected from them. The infamous "Blink of Death" that affects T20, T21, T22 and A2x systems may be due to a bad current sensing circuit. I'm not convinced that it's caused by "overcharged capacitors" and that by pushing the power button numerous times and/or holding it down for a period of time with power removed from the system, that is going to make it work again 100% of the time. I've tried the pushing/holding thing on a BoD system I have and it has never made the system come alive again. It sometimes does start working if I leave it alone for several weeks, but again, that's not a guaranteed way either.

The T23 inductors that I fix get a through scraping to remove all of the "black pad" before I re-attach them to the motherboard. That oxidation could be causing your problem (incomplete power up so that you don't even get a 1-3-3-1 memory error beep code). So far, the only inductors which have appeared to cause a general system power issue are the ones at A1/A2 on the top (just above the CPU) and the two opposite the PCMCIA slots (D9 and E8 on the bottom). If those three look good and you've stripped down the system and it still won't beep at you with no memory, then that's one I'd take apart and throw away the motherboard .

[lmiklosy]

No go! After removing the three inductors at L7, L8, L11 cleaning them and re-soldering, the board will still not drive video and no beeps. These are the inductors you referred to previously. Pity because the board powers up, drives the correct LED's, charges the battery and seems to operate normally in all other respects.

I took measurements at the inductor locations and got 500, 22, and 0.5 ohms respectively at these locations, all the inductors measure zero (hope the coils are not fused together). Do we know what the impedence at L7 should be? I took a 30x21 magnifying glass and looked over the board top and bottom again and found no bad joints, in fact this board is the best soldered board I have ever seen so I don't suspect any more broken terminals. Now I suspect the traces on the board or an IC, there could be a separation somewhere which would explain the intermittent behavior.

So it looks like this board is ready for the scrap bin. I'll hang on to it until a diagnostic solution presents itself on this forum and I can run those tests.

BTW I discovered if you mount the system board directly to the port replicator and add a battery and fan, you can power up the board enough to drive an external monitor, although the common ground back-plane is missing. Missing the ground plane is bad practice and not recommended but is sure saves some time doing these tests.

Regards, Les

[rkawakami]

Do we know what the impedence at L7 should be?

That one should be a 15uH; "150" should be printed on top. L8 is 5.2uH (5R2), L11 is 2.5uH (2R5) and L9 is 0.6uH (0R6).

Now I suspect the traces on the board or an IC, there could be a separation somewhere which would explain the intermittent behavior.

That sounds like a good guess.

BTW I discovered if you mount the system board directly to the port replicator and add a battery and fan, you can power up the board enough to drive an external monitor... <snip>

I've done this a few times, minus the battery but mounted inside the T23 base. That way I could screw down the fan/heatsink assembly. Keyboard is not even needed in most cases since you can use the dock/port replicator's power button to get things going.

[lmiklosy]

In order to repair this laptop I have two choices left, buy a tested board or buy a Lot of machines and salvage the working boards. I won't mention the IBM repair options since they are very expensive. The going rate for a tested T23 system board on eBay is $89 or $129 installed. Do I have to buy another Lot of 3-10 to find a working board with matching FRU part (FRU 12P3770) number?

Any other tinkerers out there who need a T23 system board? I could dismember a Lot and distribute the working ones to this forum. Or maybe somebody else is doing this already? -Les

[Harryc]

I have the same problem. T23, steady fan, lights sequence normally, no LCD display, no beeps with RAM removed. I've removed the ethernet card, battery, changed the CPU, all with no progress. I received the machine in this condition, and I reseated the keyboard, LCD cable, and tightened down the CPU fan and it worked for a day. Then while it was running the screen froze. This was repeatable on every boot. So I decided to replace the CPU with a known working one. Since then nothing....oh and I also replaced the LCD assembly with a known good working one as well. If I flex the left front of the palm rest there is no change in symptoms. I suppose the next step is to tear it down and start looking at inductors and surface mount components for loose or cracked solder joints, unless someone can point to something obvious that I've missed?

[RealBlackStuff]

Search for one of Ray's T23 posts about loose crystals (there are three), your symptoms sound very similar.
They need to be resoldered (like the infamous inductors). I had one of those, and that fixed it for me.
See also this pic: http://www.kawakami-ca.com/images/t23_crystals.jpg

[Harryc]

Thanks RBS. I pulled the board out today, and the inductor on the top of the board labeled OR6NH popped right off. It has corrosion on the pads on the board and on the inductor. This makes sense, because when I first got the machine I tightened down the CPU fan screws and it started posting. Since OR6NH is right next to the CPU, the board must have flexed enough to produce contact at the inductor leg/s. Looking for tips on resoldering and cleaning up things. All other inductors and crystals are tight. Still could be a solder micro-crack somewhere, but I think this is it.

[Harryc]

Well, I soldered the inductor back on (ala Rays procedure) and put the T23 back together. It fired right up and I'm typing this post from it. Another happy ending. Thanks all.