T20 - strange power on/mini-pci problem

[madrigal]

Hi, everyone!
A few months ago I obtained a T20 laptop in not so good condition - missing HDD and caddy, AC adaptor, bad battery. I bought 40 GB HDD, an AC adaptor, battery, upgraded RAM to 512 MB and CPU to 900 MHz (the old CPU was 700 MHz). In addition to that I replaced the original 3Com mini-pci combo card with Intel's one (because I prefer these NIC's) and sold the 3Com's one. Everything went fine but when I put all pieces together, installed the OS (WinXP SE) and became to use the lappy for everyday tasks, I figured out a strange problem:
1. If laptop was stopped with battery present and AC jack connected, it powers on without any problem.
2. If laptop was stopped with battery present and AC jack unplugged after that, powering on battery went fine too.
3. If laptop was stopped with battery present and AC jack unplugged after that, when plugging on the AC jack, in some cases the fan became to run on high speed, CD-ROM initializes itself, no lights lit and laptop cannot be started form start button. The only solution is to plug out the AC jack and to pull out the battery. After that laptop can be started normally (with battery present and AC jack plugged in).

After some research activity it turns out the following:
1. If I pull out the battery the laptop starts normally on AC only.
2. If I pull out the mini-pci card, laptop starts fine no matter of AC power/battery presence combinations.
3. I tried another Intel mini-pci card (from normally working T21) - the problem is still present, even in more rare occasions.

Well, i suspect that the problem is either in motherboard or in mini-pci card. Unfortunately I sold the original 3Com card and cannot test what would became with that kind of card (until I receive a new one I purchased from e-bay).

If anyone have experienced the similar problem, please let me know.

[rkawakami]

http://forum.thinkpads.com/viewtopic.ph ... 80#p530280
http://forum.thinkpads.com/viewtopic.ph ... 50#p529850

I've seen upwards of five or six T23 systems which either did not power on at all or turned on but refused to completely boot. Removal of the MiniPCI card was all that it took to restore the system to proper operation.

[madrigal]

OK, but in second case the problem was solved replacing the mini-pci card. In my case, I can reproduce the problem even after replacing the network card. I'd personally prefer if the problem is in the NIC, but i'm afraid that I have to search for new mobo

[RealBlackStuff]

The T23 Mini-pci card is either a modem, a wifi card, or a modem/wifi combo card. The NIC is a separate card.
The T20/21/22 mini-pici card is either a modem, a NIC, or a modem/NIC combo card.
You cannot compare these cards, except when they are only a standalone modem.
In the T23 cases, replacing that mini-pci card solved the problem, because the NIC was unaffected.
The T20/21/22 mobo is different. You could try a PCMCIA NIC.

[madrigal]

RBS - you are right, of course. Does that mean that I have to search a new motherboard?

[Harryc]

No, what RBS is recommending is to pull the mini PCI card out of the machine and get one of these...
http://images.maplin.co.uk/full/a88fa.jpg
That is assuming that you do not use the modem, although you could also get a PCMCIA modem card.

[madrigal]

Of course I can use PCMCIA network card, I even could use the laptop as is, but my idea was to sell it in some auctions after it's repair. Obviously I can't sell the laptop in such condition.

[Harryc]

I would try an original 3Com mini-pci combo card

[madrigal]

Yes, a few days ago I've purchased 3Com combo mini-pci card and now I'm waiting the package. On the other hand it never hurts to check in forum if someone have already experienced the same problem.