T23 System Board smoked (but looks great)

[prhowe]

Ok, so this was a stupid thing I did. I brought my T23 to work and left the charger at home. These T21-23 models have been tanks - nothing has beat them (yet) .. I have done this dozens of times before... I find a clean DC supply between 15 - 17 VDC that fits the charge port and it has always worked (even 13.6 from a running car works. I have done this since I got this laptop ~2003? with no problems.

Well, yesterday - I plugged in one that by label was good. The instant I plugged it in - the whole machine went black. And I smelled that ever so familiar smell of resistor smoke.

I disassembled the laptop down to the motherboard and looked ...and looked ... but couldn't find anything obvious ( I hate working without schematics) - I did find enough fuses to open a fuse store, but they were all ok. With a good (IBM) power supply plugged in, I get 16v through the fuses, into the IC's and the bank of 3 resistors . At the battery I see a rise from 12.28V to 12.29V when power supply is attached..

Anyway - I can't find the problem and this looked like a good place to ask Has anyone else smoked their input?

Or... are schematics available anywhere for these old beasts? And, if all else fails, there are plenty of good MBs on eBay.. I will pay for being stupid ..

Thanks in advance...

[craigmontHunter]

I had a toshiba that did that 3 or 4 times on me. It worked the whole time, and it was another external incident that killed it. Try plugging it in (with a fire extinguisher nearby), and see if it works.

Good luck

[rkawakami]

Welcome to thinkpads.com!

I've mentioned this incident several times before: http://forum.thinkpads.com/viewtopic.ph ... 35#p206635 That particular transistor is located between the LCD and keyboard connectors on the top side of the motherboard. Not sure if today's surface mounted resistors smell the same as their axial-lead ancestors when they burn up but if there was a "plasticy" odor, then that's a good indication that one (or more) of the ICs or transistors on the board is toast.

Thinkpad schematics have never been officially released to the public by IBM (or Lenovo).

[emeraldgirl08]

I had a toshiba that did that 3 or 4 times on me. It worked the whole time, and it was another external incident that killed it. Try plugging it in (with a fire extinguisher nearby), and see if it works.

Good luck

What happened with the fire extinguisher???

[craigmontHunter]

We did not need it, but the second time it happened, it was extremely spectacular, with sparks flying out everywhere (right by my hands). A couple of months later, We plugged it in on the stage, and had the fire extinguisher just in case. I later took it apart and could see where a couple of componets had blown up. I don't know what they were for, because everything worked after that .

[prhowe]

Thank you rkawakami , and everyone.

I think this is the general area of the trouble. With the small surface mount components, part numbers are abbreviated and I can't even find what the parts are that seem to be regulators or switches.

Does anyone know the part (or IC) numbers for Q5, 16, 17, 33 ?

Thanks again for the help,

Paul

Welcome to thinkpads.com!

I've mentioned this incident several times before: http://forum.thinkpads.com/viewtopic.ph ... 35#p206635 That particular transistor is located between the LCD and keyboard connectors on the top side of the motherboard. Not sure if today's surface mounted resistors smell the same as their axial-lead ancestors when they burn up but if there was a "plasticy" odor, then that's a good indication that one (or more) of the ICs or transistors on the board is toast.

Thinkpad schematics have never been officially released to the public by IBM (or Lenovo).

[rkawakami]

I don't have a T23 motherboard with me here at work, but if you use the information and "maps" (see the two links, "Top side" and "Bottom side") that I've provided in this post: http://forum.thinkpads.com/viewtopic.php?t=37956 you'll see that Q16 is a SI4802DY MOSFET. Let me know where the other transistors are by map coordinates and I'll take a look tonight. Unless somebody else beat me to it .

[RealBlackStuff]

Q5 = IRF7413
Q16 = TPC8005_H
Q17 = IRF7807D1
Q33 = SI4435ADY

[prhowe]

WOW! Thanks - I may be able to go forward in the troubleshooting with these numbers !!

I'll let you all know.. Thanks again !!!

[rkawakami]

Looking at two of my dead T23 motherboards, here's what I see on them:

Code: Select all

     30L2362    30L2484      RBS
Q5   TPC8002    TPC8002    IRF7413
Q16  TPC8005    SI4802     TPC8005
Q17  IRF7807D1  IRF7807D1  IRF7807D1
Q33  SI4435     IRF7416    SI4435ADY

SI parts are Vishay/Siliconix
IRF parts are International Rectifier
TPC parts are Toshiba

International Rectifier pages
https://ec.irf.com/v6/en/US/adirect/ir?cmd=NewCrossRef (Cross Reference)
https://ec.irf.com/v6/en/US/adirect/ir? ... igateFrame (Part search)

Vishay/Siliconix
http://www.vishay.com/mosfets/

Toshiba MOSFET
http://www.semicon.toshiba.co.jp/eng/pr ... index.html
http://www.semicon.toshiba.co.jp/eng/pr ... index.html (Cross Reference)

edit: T23 motherboard documentation post updated