T42 and T42p 15" powers on with lights & fan, but no video

[laboye]

Hi everyone. I managed to get my hands on a T42 and a T42p (which I plan on using for my personal machine. Both are the 15" models; the T42 is a pretty basic package, having an XGA LCD, the 1.5GHz Banias CPU and the basic ATi GPU. The T42p has a UXGA LCD and the 128MB GPU. Both machines will power on with the usual light sequence and will turn on the fan. No video on the LCD and no video on the VGA port. They did not respond to pressure on the GPU

I reflowed the T42 to no avail (same symptoms), but left the T42p alone. Does the FireGL GPU have the same BGA issue? What else could be wrong?

Any help is appreciated. I'll be glad to provide any more info you guys need. Thanks.

-Eddie

[ajkula66]

FireGl does have the same issue. Try pressing on the card itself while the machine is attempting to boot, and see whether it displays anything.

[laboye]

Hi. The T42p didn't budge before, but generous pressure resulted in a good image! I'll reflow the GPU and post the results. Is there anything special about the FireGL chips that I should be aware of?

-Eddie

[ajkula66]

Not really. Re-flowing it is not any different from 7500/9000/9600 from what I'm to understand, although I've never done it myself.

Good luck.

[carlisle_united]

Dosn't the T42/p have the epoxy issue like the T43?
In that case an reflow wont to a thing.

[ajkula66]

Epoxy issue is a non-issue for people who know what they're doing...and not all T42p machines have the newer type of soldering...

[laboye]

Dosn't the T42/p have the epoxy issue like the T43?

Aha! This is exactly the kind of geeky information I need! I reflow T40, T41 & T42 boards like crazy and as my business slowly creeps in larger sums of money, I've been buying nicer machines to repair. I'll be getting more and more higher-end machines to contend with (/p variants, T43s & T6xs!), so this kind of stuff would be handy!

I haven't worked on the T42p yet, but from what I recall, it has the 3-heatpipe heatsink that covers the GPU as well. I imagine it has tons of thermal paste on it (correct me if I'm wrong), which would need to be removed and reapplied. In light of the epoxy issue, a quick glance under the keyboard shows a lack of bonding material on the corners of the BGAs, including the GPU. I have seen red as well as creme-colored 'dots' on the corners of prior machines (all successful reflows). Are these 'dots' the epoxy that you're referring to?

What is the T43 issue and what defines this new type of soldering?

-Eddie

[ajkula66]

Yep, red dots are the sign of the "new" type of soldering applied after spring of 2005. Some people claim that these are impossible to re-flow properly. I've never attempted a re-flow myself, but am aware of others who have done work on this type of boards with no issues.

T42p in most cases does have a "long" fan that you're referring to, but there's not that much thermal paste as you'd imagine. Not a biggie by any means.

[laboye]

Sounds good. I'll have at it tomorrow morning. Just to clarify, the red epoxy dots are the direct cause of the issue you're referring to, right?

[ajkula66]

I wouldn't say "cause", but more of a "sign" of a particular process being implemented...

[carlisle_united]

My T43 was impossible to reflow due to the epoxy dots.
However after I removed the epoxy I realised that the GPU was so loose that it came off.

So my GPU might have been beyond saving eighterway.

[laboye]

I wouldn't say "cause", but more of a "sign" of a particular process being implemented...

That's more or less what I thought. I'll have to do some research.

@Carlisle_united: My theory is your first reflow worked on the BGA balls themselves, but the epoxy dots prevented the GPU from dropping down on them when it came time to cool. I'll definitely keep this in mind, though. I believe the T42 that I said failed has the epoxy dots. *scratches chin*

[carlisle_united]

Might be... I got tired of not geting it to work and bought a new motherboard with an Intel GPU instead, now it works as it should.

[laboye]

Hi everyone and thanks for your replies. Just to update you on what has been going on:

-I reflowed the T42 again (I have my process down pat now) and it still won't work. The PC was cheap enough for me to buy a new motherboard and still have budget left over for upgrades before I sell it.

-The T42p... heh. A 240 degree reflow was sucessful... for about 3 weeks. Following this failure, I reflowed it again only for it to fail a week later. I have repeated these 240 degree reflows on this machine 6 times all yielding the same result. I am probably going to have it professionally reballed. Where's the best/cheapest place to go for this procedure? I think I recall a $50 deal if it is stripped down to the case/motherboard. Suggestions?