Learning To Reflow

[SThompson86]

Hello all - I had a customer bring me in a Dell D620 Latitude laptop with no video. I did the normal diag stuff - external monitor-reseat the ram ect. I did get a checkerboard effect on the external monitor at one point, and that is what has lead me to believe a GPU failure.

Nonetheless, I did some research on this particular laptop, and it seems to suffer from the same problems as the infamous HP DV series, and apparently can be fixed with a reflow of the GPU chip.

I would like to take advantage of this system and try my hands at a reflow because the system is basically dead unless this reflow works or the customer gets a new MOBO, and I do not think the customer is viaing for getting a new mobo, therefore, I have a laptop to give this a go on.

I am going to ask the customer if I can try to reflow, and let her know that it may or may not work, and offer the reflow at a half off price of $50.00 if it works and no charge if it does not. If it works then I have a new skill, and I will charge $100.00 from here on out.

Ok back to the original topic "Learning To Reflow" I have been watching tutorials on Youtube and reading Howtos, and I notice people either use a Heat Gun or a Pin Torch, there in lies my question do I use a Heat gun or a Butane Pin Torch?

Second question. Some people cover the GPU with foil and some leave it un covered - Which is the best tactic?

Other than that re flowing looks like a simple process.

Thanks in advanced, and please if you guys have any other diagnostic tactics for me to try on this thing before I reflow it, please let me know.

- Shane

 

[Larry Sabo]

I'd highly recommend this blog by someone who does tons of reflows and component-level board repairs. He goes through a lot of the myths about reflow advice found on YouTube and debunks it, and spells out what he does in some detail. Personally, I'd want to use a hot air rework tool that provides precise temps. Absent that, a heat gun on low setting seems advised, as the temp you want is around 250C -- much lower than you'll get with a pin torch (which I assume is an open-flame butane torch) -- for 2 - 3 minutes. The key, according to the bloggist, is the use of proper (rosin-based) flux, as it oxidizes and begins to smoke at the temp you want to achieve, just when the solder begins to reflow. That's what he uses to tell that he's got the temp right. Let us know how you make out!

 

[SThompson86]

for 2 - 3 minutes. The key, according to the bloggist, is the use of proper (rosin-based) flux, as it oxidizes and begins to smoke at the temp you want to achieve, just when the solder begins to reflow. That's what he uses to tell that he's got the temp right. Let us know how you make out!

I did see a guy who put a quarter on top of the chip and then a cut of solder on top of the quarter. I guess he was using the solder to see the visible melting point?

Thanks

 

[vdub12]

Keep in mind also that some reflows will last the life of the notebook and some will last a day and fail again.

 

[SThompson86]

Keep in mind also that some reflows will last the life of the notebook and some will last a day and fail again.

I will deffiently let the customer know this, and offer a refund if it does not work.. I find it hard to really warranty a re flow.

 

[MrUnknown]

well, reflowing isn't simple because you can't see when all the solder is melted so it is a bit of a guessing game.

I would recommend a hot air rework station with a tip the size of the chip you are working on.

Foil helps protect the other components from the heat, the ones putting it on the chip to be removed makes no real sense to me.

I have not done a reflow yet, so take my advice to be no better than the youtube videos.

 

[Lou Horton]

Even if you do everything perfectly it definitely isn't a guaranteed fix. If it does work and you add nice copper shim and good thermal paste, usually the fix will last very well. I'm not sure if that Dell has a bios update that makes the fan run more like the HP's, probably want to check into that also.

The blog that Larry linked is about the best around. The flux is very important as is a very stable and secure mounting of the system board. Any vibration or movement during the reflow process and you can forget about it.

Ideally you should also have a pre-heater beneath the board to keep the temperatures more even to prevent the board from warping.

Best of luck to you.

 

[SThompson86]

Knowing that this is not a solid fix, makes me less willing to try it especially when I do not have the correct tools. I do not want to invest in a hot air station, for I am not to big on fixing hardware on a component level. When it comes to bad mobo`s I generally recommend getting another mobo or just getting a new computer if its an oldie.

 

[SThompson86]

Do you guys find it worth doing reflows? Just from what I am reading on here and random places on the net it sounds like a iffy fix.

 

[Larry Sabo]

To be completely open and honest, I haven't done one myself, in spite of having all the equipment required. I've been turning away re-flow work because I'd rather have no customer than an unsatisfied customer, and by all accounts, it isn't going to last long enough to take a chance. While Kevin at that blog has had excellent success, he has had many years of top-level experience soldering. However, one only acquires experience and success through training and practice. Go for it!

 

[vdub12]

What I would do is if the customer decides that a mobo is to expensive try and see if they will donate the notebook to you so you can practice on it. Then you can see for yourself how reliable it can be. Also maybe even try reballing it.

 

[hext]

Hi

I suggest listening to this

Reballing over Reflow

not affiliated with me or my company anyhow but an interesting podcast explaining how reflow isn't an exact fix..

 

[MobileTechie]

I've done a few now.

I found the temp control of the hot air station not to be relevant because setting it to the correct temp and heating the cheap resulting in about 150c and no higher. Mine at least does not output enough heat energy to heat the chip up quickly enough. I can use it but it takes a lot longer and I have to have it on max temp. I think it would be safer to have a larger heat gun set at a lower temp. However it works if you don't mind the delay and being careful.

I use an IR thermometer. It is not terribly accurate and involves waving it around to scan the whole chip and taking the highest temp as the real temp. I paint the GPU black with a perm marker pen so that it gives more accurate temp readings.

Obvously do not cover the gpu with foil. I cannot see the solder on top thing working because the top will be much hotter than the bottom since it's getting blasted by the heat directly.

This is the temperature guide I follow: http://www.excelics.com/Solder Info.pdf

 

[meanderer]

I have done a few reflow jobs, 2 on my own laptops and 1 on a customer. Both of mine recur after a few weeks or so with moderate usage. It is definitely not awfully reliable means. At least it's good enough to get it running and migrate to a new computer.

Here's what I did, please advise improvements if you can:
1. take the board out
2. cut a piece of foil in a few layers, cut out a hole for the size of the chip (optional, cut a hole for bigger chip and use a smaller strip to fit smaller chips)
3. take a Aoyue 852A rework station. I use a .5 inch circle tip, turn it on and set it to 420 (don't know if it's F or C, there's no indicator)
4. using that heat gun, I go to the bottom side and heat up the board for about a minute using circular motion.
5. then I go to the top, tape down the foil. Apply rosin flux on the edge and top of the chip, and using the same circular motion. Heat up the chip for about 4 to 5 minutes. Flux will start to smoke.
6. turn down the temperature by 50 every 10 seconds maintaining the same motion. once it reaches the lowest allowed by the rework station. I turn it off and leave it alone for 15 minutes.
7. reassemble and give it a shot.

So far, all of them I had worked on have problems resolved. 1 of mine come back after a month. The one customer called back while I was away, I tried to call back but he didn't answer. I wonder if his problem came back but I can't be sure.

 

[16k_zx81]

Best option for a reflow is an IR station. More precise and local temperature control than a hot air rig.

We do 2 months warranty on reflow jobs. Thats about all its possible to offer.

We charge $250 and suggest to the customer they may want to sell their laptop after the job is done.

On the DV series, do a BIOS update after you have seen to the chip.

Better option than reflow is reballing, but its hell difficult to do (Ive never tried). There's an interview with a guy in the UK who specialises in it in one of the Podnutz podcatsts - just search for reflow to find it. From memory I think he said he nuked about 100 boards before he got the method to work reliably. Apparently its a longer-term solution though.

[edit] I think the link above is about the same podcast

 

[gazza]

Reflowing chips, forget it!

With the price of laptops coming down every month it is not a economical solution for customers anymore.

 

[4ycr]

reflowing on a cheap laptop is not worth it but I have one that cost a grand a couple of years ago. After advising my customer of the service from the guy in the podnutz podcats he wants me to reflow it.

I did warn him that it could only last 3 months tops

 

[gazza]

reflowing on a cheap laptop is not worth it but I have one that cost a grand a couple of years ago. After advising my customer of the service from the guy in the podnutz podcats he wants me to reflow it.

I did warn him that it could only last 3 months tops

A couple of years is long time in the computer industry, still not worth it!

 

[Lefty]

I don't recommend reflows to customers because of the lack of reliability. How long will it last? I'm not willing to take the chance of the unit breaking two weeks down the line and getting a disappointed customer.

 

[SThompson86]

I don't recommend reflows to customers because of the lack of reliability. How long will it last? I'm not willing to take the chance of the unit breaking two weeks down the line and getting a disappointed customer.

Yea I ended up coming to the same conclusion. I just thought about would I like paying some one $100+ to do this to my personal computer, and I was like ehh... I am just not going to even bother learning how to do this.