Upgrading a GeForce 8400M GT video GPU

Have a desktop Sony VGC-LT35E which has no slots except for RAM. The motherboard looks more like a laptop than a desktop. Currently, it has a defective video chip connection. The chip has been reflowed twice and has again detached itself. I plan to reball the chip, which should provide a permanent fix. I would like to upgrade the chip to a higher rated one in the same nvidea family . The current chip is an GeForce 8400m gt. would this modification be possible? Say up to a 8900?

 

There is no 8900. There is (or was) a 8800m GT but that had a 256 bit bus to memory so I doubt you'd be able to use that. Technically, you should be able to use a 8700m GT if you find one or anything below that.

 

Thank you for the reply. Trying to find an 8400 is difficult. So far the only ones, used, are in China. The reviews from purchaser's are dim: lost order, counterfeit chip, etc. I look to defective system boards for parts. I don't know if I will gain much from an 8800 but since I flowed the 8400 twice, I thought it would be better to go to another chip and then why not upgrade.
I am going to do the reballing myself. looked on You Tube and it looks relatively easy.

I do have two question:
1. How do you determine the size of the balls for the chip
2. And, where and how do you get the proper mat for placing the balls?

Don't know if you have this expertise, but hope someone out there does
Thanks again
afterburner1

 

DIY reballing at home, by someone who has never done it before, doesn't know the ball size and doesn't have the template? Please tell me you are joking? Give it up. The machine is ancient if it has an 8400 and would be trounced my a modern Haswell+ CPU with integrated graphics. Time to move on, honestly. The 8400 was mainstream crap when it was launched and in the last 7 years it has not improved....

 

There are other, nicer ways of saying that. Who can tell me one, hmm?

OP, if you are doing this for fun, go ahead. If you are doing it to learn something and don't mind if your system breaks, go ahead. However, if your system is critical to you and you cannot purchase a new one if this one breaks, then don't. Even with experience, what you are attempting to do is not guaranteed to work.

 

///Boy you guys are hard on an old guy!
I enjoy working on computers as a hobby. This computer is a desktop all-in-one and pretty. It has a wifi board and mouse.. It is a core 2 MODEL: SONY VGC-LT35E. Since I don't game, core 2 is ample for my needs Can also stream quite well. Found similar one for my wife and reflowed both. Her's is running fine.They both function as TVs and can be hung on the wall
Look up reballing on YouTube you will find it is not formatable. I figured out the stenciling and the ball size. Most balling kits are out of china and Chinese products are either very good or very bad.; nothing in between!
Now let me tell you about me I am 85 years old and I started fixing clocks when I was ten and until a few years ago I was repairing and improvising on Lotus and Jaguar electrics...Taking part a laptop is a piece of cake as far as I am concerned (Putting it back together is a little challenging. At my age the second thing to go is the mind!).....
Now I need your help. Do you think a Nvidia GeForce 8400M GT can be replaced by a Geforce 8600 GT taken from a PCI card. Note "M" is missing in the 8600. Could mean Mobile???
As I said before Chinese chips are unreliable.and agree with you they are hard to find. 8600's are plentiful on the internet but only in PCI cards. I would really appreciating hearing from you guys

afterburner1 (clue on my past)

 

The M stands for mobile, yes.

They both share a lot of the features so I don't see why not provided the package is the same. THAT I have no idea about. If you can verify that the package pinouts for both match, it would work because the memory bus width is the same for both.

 

It's a lot more complicated than that. The motherboard must support the chip in the BIOS and/or the VBIOS so while it might fit it more than likely won't work electronically, especially because you are replacing the *die* not the *card.* The card's interface is PCIe but the die's interface is proprietary and much much different than replacing a socketed CPU.

Additionally, a desktop 8600 is equivalent to a laptop 8800m or so, meaning your TDP (power usage) would be completely out of whack (an 8400m consumes 1-10W of power, an 8600m consumes 20-100+W). Even if somehow you managed to edit the VBIOS to accept a different manufacturer's version of the chip, and magically used crazy low-level BIOS hacking skills with all the checksums, you would be faced with a chip that is consuming way too much power. It's akin to sticking a V10 engine in a VW Beetle while keeping everything else exactly the same and wondering why it has trouble starting and why it overheats. Though I suppose by this point you could lower the operating voltages and regulators to what you need.

I hate to rain on your parade but clocks and computers quite different from one another at these levels. I laud your ambition, but feasibility and (worst of all) proprietary interfaces are against you. It'd be one thing if it were difficult but known, this is beyond impossible and there are zero guides on replacing GPU dies with different ones.

The hard solution would be to find another 8400m, but the 8400m and 8600m are both plagued by poor soldering joints and will eventually fail again. The easier solution would be to move on or find an entire new motherboard from a similar model (if they exist) and replace it. It's very hard to replace a proprietary motherboard though.

Maybe you could see what the internal LCD connection is. If it's LVDS like most laptops, you might be best off getting a new motherboard+CPU with an LVDS connector. Still a hack but much much more feasible!

 

Thank you for your responses; they are sincerely appreciated!

Some or even most of the technical detail was over my limited expertise. I understand the chip might not match the board and there could be higher voltages involve and excessive heat generated. And the message is DON'T DO IT.
Going back to square one, I only wanted to do it was to upgrade the 8400m since I planned to reball. Since an upgrade is doubtful, I will consider reballing the current chip.
Last night I did reflow the 8400m and it works. I foiled the area around the chip, put a penny on the chip with solder on it and used my heat gun and heated the penny till the solder melted and continued for another ten seconds (long sentence) This was the third reflow
As I have heard the problem is not with the chip, but with the low lead solder. That being the case a reball with lead/tin solder balls might solve the problem
I also bought another motherboard with a bad chip, I suspect. When it gets here I will reflow it and test it and keep as backup.
As I said before I really like these computers and th e investment for both was only about $200 plus the $32 for the new motherboard.

Thanks again for all your info and time,
afterburner

 

You might try asking this in the Sony forum here. Mobile GPUs, even in all-in-one computers, can vary a lot in terms of compatibility among manufacturers. For example, my Dell laptop can only accept Dell-manufactured 8400M GS and 8600M GT GPUs, due to a proprietary interface. Some laptops can take any standard mobile GPU of a certain physical size. As I remember, Sony laptops from that era tended towards the more restrictive and proprietary options, but I know less about their all-in-ones, and the only Sony that I've used extensively is from last century. If there is someone here who would be able to tell you definitively what will and will not be compatible, you're most likely to find them in the Sony forum.

That generation of GPU did indeed have a problem with low lead solder, leading to its unusually high failure rates. I'm actually rather amazed my GeForce 8600M GT has not failed me yet. It's an interesting theory that reballing it with lead/tin solder might solve the issue. I don't recall having read about someone having done that. I'd be interested to hear whether that solves the problem long-term if you do try that.

 

I, surprised that reballing hasn't been mentioned. I suspect it is because of the cost and uncertainty. I was concerned about reflowing until I studied several YouTube sites and settled on the procedure above. The reballing kits/items sold on Ebay (again Chinese) seem to be adequate to accomplish reballing. I think what I will do is practice on an old motherboard, and if it works, do my Sony boards (Faint heart never got fair maiden) I do solder well and that seems to be the key to success
I will update on my progress.
Afterburner

 

Didn't think I would get back this soon.
Found an old motherboard with an Nvidid GPU. First step after preparing the board was to heat the chip. No matter how much heat I applied, it would not release from the board. I am sure the chip is cooked and of no more use. I did go to another Youtube site to look for more info and found a tutorial on setting up to do reballing. The moderated said he went through fifty boards before he got the technique in hand. This is the site , if you are interested: youtube reball - Bing Videos
Altho not being able to release the chip with the excessive heat, I wondered how I could reflow the 8400m chip with minimal heat and have it work???? Leads me to believe my "Do it Yourself Surgical Kit (for additional SandH you can get two" might not be a good investment.

My decision after looking at the technique and equipment, and not having fifty practice boards, is to send my board away for reballing.

Sorry: Referenced site would not post