Dead MB or just a fuse?

[ohthinker]

I cringe as I type this, because it's the sort of head-smackingly stupid thing I'm always warning other people about. But all it takes is a little distraction and carelessness (and a massive dose of idiocy) to plug the wrong power adapter into your computer. Which is what I did. Blasted my poor T23 with a 30 volt power adapter from a printer.

At least it didn't seem to experience much pain. It made a bit of a thumping sound, which might have come from the speakers - I'm not sure. No flames, and none of the magic smoke escaped from the case, but it, uh, does smell a bit smoky now.

Of course it won't power up at all. With the proper adapter, I mean.

Is it worth opening up and checking the fuses, or is it likely that a couple (or a bunch) of semiconductors have blown to protect the fuse? Is it apt to be salvageable, or should I now just consider this guy a transplant donor for my other T2x machines and chuck him in the parts box?

Thanks to anyone who might have experience with this (and admits to it).

A Chagrined Not-thinking-pad Owner

[rkawakami]

I haven't (yet) applied the wrong AC adapter to a Thinkpad. I did plug in a Sun Ultra 5 that was set up for 110VAC into a 220VAC outlet SNAP!, followed by the unmistakeable smell of burning/burnt electronics (Hello power supply and motherboard swap!). I've smelled the same from some T23s when a part blows out; typically a MOSFET will go before any of the fuses. My guess would be that your T23 has taken its leave to Silicon Heaven. You may be able to spot one (or more) ICs that have a hole in the top of the package, where there was once a smooth surface. Then, assuming you can figure out exactly what was there, source a replacement and solder it to the board, you just might be able to revive it. Then again, there could be other damaged components which don't show any outward signs of being distressed. It probably is worth it to open it up just to see if you can find any parts that are now visibly damaged. For reference, here's a photo showing some of the fuses on the T23 motherboard:

http://www.kawakami-ca.com/ibm_t2x/let.jpg

F2 (top edge of photo, just left of center) is the one which protects the DC input. That one may have blown, but if you smell what I think you're smelling, then look for something like what I've circled in black. That's a MOSFET which I saw develop an orange glow for about a second, followed by a crater and a then pillar of magic smoke.

[ohthinker]

Thanks for the assessment. Bummer, but not too surprising.

Shame the manufacturers don't standardize on power plugs, with each voltage a different size, to protect equipment from dumb screwups like me.

But on the positive side of the aisle, now I may have a nice functional LCD for that T20 with the dead backlight. Eh, does T23 memory work in earlier T-series machines? I could use some more for one of my T22s.

[rkawakami]

There is a very small chance that the memory in your T23 will work in the earlier T2x series. It would have to be a 256MB (or smaller) low density module. Those can be identified by simply counting the number of memory chips that are installed on the module. If there are a total of 16 (8 per side) chips on the 256MB module, then that's low density and it should work in the T20-T22 systems. If there are only 8 chips, then it won't work (those are known as "high density"). Smaller modules have a similar relationship; a 128MB module with 8 chips is low-density, while the same sized module with only 4 chips is high-density.

[automobus]

Shame the manufacturers don't standardize on power plugs, with each voltage a different size, to protect equipment from dumb screwups like me.

Sony and other manufacturers have done just that. I had a VAIO laptop from 1999 and one from 2004, they both used 16 Volts through EIAJ-05 plugs (although the AC adapter can put out 4 Amps, which is double what EIAJ plugs are supposedly designed for). I am not sure about their current lineup.
The PSP uses 5V through EIAJ-02 (and so do some CardBus USB adapters).

[cadillacmike68]

T23 memory WILL NOT work in earlier T2x series. That's a bummer, but it's also a fact.

[Unknown_K]

Higher voltage probably blew something up before a fuse would react (look in the power section). Probably not worth fixing unless you can do that work yourself.

Where in NE Ohio are you?

[Majestic]

T23 memory WILL NOT work in earlier T2x series. That's a bummer, but it's also a fact.

I've had no problem swapping modules between the T23 and the earlier T2x series. You just have to make sure they are low density and 256mb or smaller as Ray had previously mentioned. The T23 can use both high and low density modules where as the earlier T2x series can only use low.