Totally dead T43 - thoughts?

[davidbaker999]

Hi there

I am repairing a T43 for a friend who poured a large glass of wine into it. I'm a Mac engineer (pauses for taunts... ) and this is my first expedition into the IBM world so I would appreciate any advice you might have.

I have removed and cleaned the keyboard and the hard drive and tested them and they are both working fine.

I have extensively cleaned the logic board and all the components I can see with Maplin Electronic Solvent Cleaner (basically alcohol in an aerosol) and dried it with compressed air. I have also left it open for a few days for good measure.

When I give it power though and press the on/off button nothing happens. There's a good voltage (about 15V) coming into the port but beyond there I don't know what to look for.

I am assuming some contact has corroded/shorted but I don't know how to test for that.

(a) Are there any specific pins I can check the voltages at, say, for a trickle voltage that needs to be present before the laptop starts up?

(c) Is there a schematic available on the web somewhere? I have the Service Manual but it would be good to see where the power is supposed to be on the logic board.

(c) Any other thoughts about getting things moving again?

Thanks again and looking forward to hearing from you guys.

David

[BillMorrow]

was it ON when he dumped the vin-ordinaire all over the keyboard..?
this is critical..
and what was done immediately thereafter..?

no schematics..
at least none that i am aware of outside of ibm/lenovo..
besides those are at least 3 or 4 level PWB's..

about the wine..
if it was a really dry wine there might be some sugar residue that escaped the cleaning process..

also, the keyboard might be shorted out with some residual moisture between the surfaces of the membrane..

the best you can find in the generally available publications would be the hardware maintenance manual..

start here:
http://www-306.ibm.com/pc/support/site.wss/home.do

the only other things that you might try would be:
pull all unneccessary to operations, parts..
i.e. add in memory, HDD, CD drive, wifiminiPCI card and so forth..
just see if the basics work..

also check that all plugs are back in place and not dirty with sugar..

if you can lay your hands on another keyboard, it might help to determine if the keyboard is working or not..

[davidbaker999]

UPDATE (see bottom of post)

was it ON when he dumped the vin-ordinaire all over the keyboard..?
this is critical..
and what was done immediately thereafter..?

Hi Bill

Yes, I believe so. Then she turned off immediately. Later she poured tap water (a few glasses) after the wine until the water ran clear. Then she left it open to air dry.

Then she called me.

also, the keyboard might be shorted out with some residual moisture between the surfaces of the membrane..

The keyboard is fine. I have tested it on another machine. (Which is I guess bad news. I was hoping that would be the faulty part.)

the best you can find in the generally available publications would be the hardware maintenance manual..

Thanks. I've downloaded that.

the only other things that you might try would be:
pull all unneccessary to operations, parts..
i.e. add in memory, HDD, CD drive, wifiminiPCI card and so forth..
just see if the basics work..

also check that all plugs are back in place and not dirty with sugar..

Great. Will see what I can do.

Thanks

David

UPDATE:

I have now stripped it down and removed the Bluetooth card. When I connect the power there is a regular quiet ticking sound (about 4 per second) coming from somewhere on the top left part of the logic board underneath where the Bluetooth card is/was. I'm sure this is bad news - I have never come across a logic board ticking, but has anyone else?

[lev]

UPDATE (see bottom of post)

I have now stripped it down and removed the Bluetooth card. When I connect the power there is a regular quiet ticking sound (about 4 per second) coming from somewhere on the top left part of the logic board underneath where the Bluetooth card is/was. I'm sure this is bad news - I have never come across a logic board ticking, but has anyone else?

Switch-mode power supplies often make exactly that type of noise, when they're either broken, or they are connected to less than their minimum load (eg if they are disconnected from their load).

Lev

[jdhurst]

<snip>
Switch-mode power supplies often make exactly that type of noise, when they're either broken, or they are connected to less than their minimum load (eg if they are disconnected from their load).

Lev

Is that correct? I would like it to be correct. I have the Power Supply out of a 7704a oscilloscope that I bought for parts for next to nothing. I think it worked when I got it. I started dis-assembling it to retrieve the parts I wanted. When I got the Power Supply out on my bench with nothing attached, it began to tick as you describe. Maybe it is good. It is an early switching power supply.
... JD Hurst

[davidbaker999]

UPDATE (see bottom of post)

I have now stripped it down and removed the Bluetooth card. When I connect the power there is a regular quiet ticking sound (about 4 per second) coming from somewhere on the top left part of the logic board underneath where the Bluetooth card is/was. I'm sure this is bad news - I have never come across a logic board ticking, but has anyone else?

Switch-mode power supplies often make exactly that type of noise, when they're either broken, or they are connected to less than their minimum load (eg if they are disconnected from their load).

Lev

I suspect it is connected to less than its minimum load. When not connected to the logic board the DC power in shows a voltage of about 15-16V. When it is connected to the board it shows 1-2V and there is a clicking sound. The contacts in this area are very corroded so I am guessing something is shorting out the power so there is not enough to start the machine.

Does that sound right?

[lev]

<snip>
Switch-mode power supplies often make exactly that type of noise, when they're either broken, or they are connected to less than their minimum load (eg if they are disconnected from their load).

Lev

Is that correct? I would like it to be correct. I have the Power Supply out of a 7704a oscilloscope that I bought for parts for next to nothing. I think it worked when I got it. I started dis-assembling it to retrieve the parts I wanted. When I got the Power Supply out on my bench with nothing attached, it began to tick as you describe. Maybe it is good. It is an early switching power supply.
... JD Hurst

Yes. I used to salvage power supplies from broken PCs to use for projects (before I got a real lab bench power supply). They all had a specification for the minimum current/maximum resistance that could be applied to some of their lines (usually the +5v line needed the most, and -12v didn't need any). If you would just power it up on the bench with no load it would tick like that. No permanent damage that I could see (but these were chunky PC/XT era supplies that weighed many pounds....).

See:
http://www.pcguide.com/ref/power/sup/output.htm

Edit: a more direct link:
http://www.pcguide.com/ref/power/sup/ou ... ing-c.html
[/b]

[jdhurst]

<snip>
Yes. I used to salvage power supplies from broken PCs to use for projects (before I got a real lab bench power supply). They all had a specification for the minimum current/maximum resistance that could be applied to some of their lines (usually the +5v line needed the most, and -12v didn't need any). If you would just power it up on the bench with no load it would tick like that. No permanent damage that I could see (but these were chunky PC/XT era supplies that weighed many pounds....).
<snip>

Thank you. I pulled the power supply out of the parts box and started it up. It ticks away, and the voltages are not accurate (no load), but the postive and negative status of the voltages is good. So the power supply is probably OK. Thanks again, .. JD Hurst