Thinkpads Forum

I have here a ibm thinkpad 770X. I bought a new adapter for it and when i putted the adapter to my thinkpad the powerled was on for about 1 second and then nothing anymore. The litle lcd screen shows nothing anymore. The adapter i bought gives the good voltage and the right polarity so i don't know what happend to my thinkpad.

Is he dead or is there something i can do to bring it alive?
I hope somebody can help me.

what is this adapter..?
is it the IBM one intended for a thinkpad 770X..?

if the voltages are correct and the battery is not totally dead and shorting it out, it should work unless the 770X itself is dead..

take out the battery if you have not already done so..
than try again..

but be SURE that the adapter is correct..
if it is not, then you probably killed that 770X..

There is no battery in it, I use an universal adapter which can be use for more laptops. You chan choose the voltage and en the polarity. I checked several times that the i choose the right voltage and right polarity so that can't be the problem. The new adapter works fine with other laptops so i don't think there is something wrong with the adapter. I also checked that the voltage at the output was correct so i took a Volt-meter and that showed 16V what is needed for the laptop.

I also checked that there was some voltage over the battery pins in the laptop. I measured it on the pins left and also on the pins rignt where usually is putted the cd-rom. They gives both a voltage over it.

So is there somebody who knows what i could be killed with using this adapter or did i something wrong with using this adapter?
Is there a way to fix this problem?

you STILL do not say what the voltage is that you applied and what the amperage available from this non-IBM adapter is..
its essential to know this before going further..

it COULD be that that adapter is not supplying sufficient amperage/watts even though the voltage might be correct..

and what IS the polarity on the center contact..?

The laptop needs 16 V DC and the center of the connector(male connector) is a +
The amperage = 3,36 A

The adapter gives 16 V DC also a + for the center (female connector)
The max amperage that the adapter can give is 3,5 A

So i think this adapter is good for the laptop or is there something that i forgot to check?

Everything appears to be correct with the power supply (polarity, voltage, current). My guess would be that a fuse on the motherboard is now open because your first post said the laptop was on for one second and then shut off. Has the laptop ever worked before? If yes, was it with another adapter?

The laptop didn't work yet here because i bought it without the original adapter. Before i bought the new adapter i tested the laptop with an adapter of 15 V and other specs are also ok and the powerled went on and the little lcd worked also, i didn't started up the laptop because the voltage was not 16 V so i did'nt want to kill my laptop os i bought a new one which should work and after 1 second no powerled and no sign on the litle lcd screen.

I opened the laptop and all looks normal. Nothing is burned black, I checked all i looked for a fuse but i can't find one. If a fuse is broken, where can i see it? But if it is a broken fuse how is it possible that there is still a voltage over both battery pins in the laptop?

I'm no expert with the 770 series, but it sounds like the power circuitry is fried. There might be a fuse, but I doubt it. It is very easy to kill a computer when using the wrong power adapter settings. Its is always best to use OEM power adapters to avoid things like this happening. IF there is a fuse, I have no clue where it is, but if you find it, FRY's would definitely have the fuse you need (I had to find a very specific fuse for a sound board and FRY's was the only place that had it.). If you don't have a FRY's, Radioshack would be the next place to look.

The OP appears to be in Belgium. I don't think Fry's has expanded that far .

If the 770 systems used the same fuses that I have found on the 600X and T23 motherboards, then they are surface mounted ones. I am more familiar with the T23 board. I have found about a dozen different types of fuses on that board. It could be possible that the voltage appears on the battery terminals, yet doesn't reach elsewhere in the motherboard because of a blown fuse.

And yes it's true, usually semiconductors will blow first, thus protecting the fuse .

Now i know my thinkpad is really dead.
I looked for fuses on the board of the thinkpad but i don't know how they look. I think i can buy me a new thinkpad, on ebay i can't find a board for it.
But thanks to all for helping me.

michielske wrote:I looked for fuses on the board of the thinkpad but i don't know how they look.

Here is an example of what the fuses look like on a T23 motherboard:

http://www.rkawakami.net/ibm_t2x/main_fuses.jpg

Generally, fuses will have a marking of "Fnn" next to them ("nn" are numbers). You can check them using your multimeter. The problem is that once you know you have a bad fuse, finding a replacement can be hard.

when our *japanese*brand* blew an input fuse on account of
non-proprietary AC adapter, and we couldn't find a replacement, by
means of some fuse wire and 2 short leads, we hacked up something,
works fine. See yr local electronics supply store.

rkawakami wrote: Here is an example of what the fuses look like on a T23 motherboard:

http://www.rkawakami.net/ibm_t2x/main_fuses.jpg

Generally, fuses will have a marking of "Fnn" next to them ("nn" are numbers). You can check them using your multimeter. The problem is that once you know you have a bad fuse, finding a replacement can be hard.

I have seen a lot of these things on the motherboard. I go check every fuse that i can found on the motherboard. But my guess is that the fuse must me very near the powersupply because the powerled gives no light when i put adapter in. If I found a bad fuse and i can't find a replacement, where can i find the properties of that fuse to search for an alternative fuse in my local electronics store?

Hi to everyone,

I'm new in this forum . I found very valuable info about IBM thinkpad 770 , 600 and others. I had a TP 380 XD before ,it was very good laptop , but there was no chance to upgrade it.
Now I'm trying to have a laptop as good as TP380 XD and can be upgraded. For this reason I bought a second hand TP 770 X .

When I searched in google any info about power on problem of my 770X, I found this forum and learned many features of my 770x that I bought a couple days ago.

I faced same problem with michielske who has power on problem with 770x.

When I bought this 770x, it had no AC adapter .
When I tried to turn it on with 15 V 3 A Toshiba AC adapter , but there was no any signal and something that shows the TP is connected to AC adapter.

Then I opened the keyboard to see fuses. There are many fuses on DC-DC board and all are OK. There is 15 V on all fuses. But there no any voltage on mother board and on battery connectors.
And it does not work with battery too.

All capacitors have 0 V on DC-DC board. I think the DC-DC board is broken and should be replaced.

If there is any specific problem please let me know.

Thanks in advance.