Thinkpads Forum

OK, I don't know what I did. I was messing around in the BIOS (trying to get it to boot from CD) & I'm pretty sure that I didn't change anything important, & upon reboot, it just keeps powering up for like a second & then shutting down again. I removed the BIOS battery, Power Battery, & the Power Plug for a day to clear the BIOS just in case. No difference. So, I replaced the BIOS battery. No difference. If I don't have the Main Battery in, it won't do anything. Am I guessing right that the Main Battery is necessary for the laptop to boot & could it be that the Main Battery is messed up?

I don't know what you did, but a 390 does not need a battery to boot if it has a good power supply connection.

I'd try getting right down to basics. Strip out any added memory, and the hard drive, and see if you can get into the bios/setup

Were you messing with the undocumented bios editor?

I wasn't sure if it needed the battery or not, but I do know that if the battery isn't in the laptop, it won't even do the constant cycle thing. I'm pretty sure that the AC power cord is good, because the battery charge light turns on every time that I plug it in. I'll try stripping the thing tomorrow.

Look at the DC board as a culprit if removing extra memory, hdd, CD, etc. My 390X which I use everyday pulled a simillar stunt and swapping out the DC board fixed it's issues.

Yeah, I'm starting to think that that may be the problem. I've pulled everything one at a time & put them back in random orders & nothing. I then took the laptop apart & put it back together & while doing so, noticed that the DC board (I'm assuming that you're referring to the L-shaped pc board that the battery's plug into) was looking warped. I tried to reseat it & make it as flat as I could & now when I power the laptop, it will come on with or without the battery, but the screen still never gets to showing anything. I'm gonna try reassembly one more time & then I guess I'll try to get another board on ebay.

The L shaped board is the DC board. I saw a few floating on ebay the other week. Should be easy to find and they are pretty inexpensive these days.

Keep us posted as things develop.

We've recycled laptops before, where they work before we meddled, and not after we've dissected it and reassembled it. Oxidized contacts, dirt in pins, etc. What I am trying to say is that the odds are against you when you decide to open it up. Out of desperation, you can rebuild it *again* once more, taking care with all the male/female contacts on anything, down to the wire. Especially cellophane ribbons, those fracture easily with age.

I'm thinking that you're right, because every time I put it back together, it seems that it either works a little better or a little worse. I've replaced the battery board & it did kinda boot. It now beeps & the power light looks fine (with or without a battery), however, I never get anything on the screen. I've tried hooking up an external monitor to check if it's the LCD, but nothing on that either.