Advice for a new BGA rework station owner please

[dicky96]

Hi guys
So I finally bought a BGA rework machine - something I've been planning for a long time

After several months looking on forums and chatting with sellers I settled for a semi auto 3 zone IR + Hot Air machine with optical alignment, the LY G720.

https://www.aliexpress.com/item/32839661523.html

I hope to work on motherboards up to full size ATX size, replace LGA sockets etc and fix graphics cards - that sort of thing. The seller convinced me this machine is up to the job, and has included a selection of nozzles tailored to my usage. I hope that it was honest advice!

So while I am waiting for my shiny new machine to arrive, all and any advice for a new BGA owner would be much appreciated, and hopefully prevent me from destroying too much stuff learning to use it!

Thanks
Rich

[diif]

Re: Advice for a new BGA rework station owner please

You've ordered stencils, lead balls and decent flux, desoldering braid?
Collect together some scrap boards so you can use them to get your profile correct.

[dicky96]

Re: Advice for a new BGA rework station owner please

Hi diiff

No I need to order those. apart from the desolder braid

What flux would you recommend, maybe I already have something suitable?

I have some scrap motherboards. I understand this needs a lot of practice but I am hoping a semi auto machine will help to give repeatable and reproducible results?

I also have 17 faulty gaming motherboards coming I got in various auctions off ebay - mainly they need cpu sockets and almost all are LGA1150 so I need to order some of those

I also got 3 faulty GTX 780 ti graphics cards so far and I am trying to get more of the same model - I'm trying that particular model as they are affordable as faulty, and they the fastest GPU that was ever made that is compatible with Windows XP and therefore they have a decent resale value if I can fix them because of the retro gaming market

Am I going at this the right way. sticking to batches of the same type?

And is that at least a half decent BGA machine I bought? it was quite an investment.

Rich

[diif]

Re: Advice for a new BGA rework station owner please

Seems decent with the 3 zones, genuine Amtech 599 is what I use for reballing.
Does it come with profiles already set or have you got to put those in yourself?
If you have to set it up yourself you will need scrap boards to get the profile right

[dicky96]

Re: Advice for a new BGA rework station owner please

I assume it comes with some preset profiles but to be honest I don't know. It comes with menus in english, I did ask that

Here is a dumb beginners question - how much does the profile depend on the board being worked and how much on the component?

For example if I am replacing LGA1150 on various Asus and Gigabyte gaming motherboards, would the profile be the same each time because all motherboards would have a reasonably similar mass?

If I then wanted to rework or replace southbridge or SIO on the same type of boards would the same profile work again because it's the same thermal mass?

Same question for GPUs/Graphics cards

Another interesting thing - the seller insisted several times when asked if this machine can place LGA sockets with optical alignment, that it can. I can't understand how it does that as the LGA socket has a square hole in the centre but he insists its OK because the vacuum is strong enough to do it without damaging any pins in the socket.

In fact when challenged he said he does it himself with this machine but didn't elaborate on how. I know replacement sockets come with a plastic shield over the pins (and maybe it is made of the same plastic as the socket?) but all the videos I ever saw of the sockets being changed manually had the pin shield removed first.

cheers

[dicky96]

Re: Advice for a new BGA rework station owner please

I found that amtech flux on ebay - £30 for 30ml. It doesn't seem cheap unless it lasts a long time - how much is typically used on one job?

[diif]

Re: Advice for a new BGA rework station owner please

Yeah, the genuine stuff isn't cheap but then quality stuff usually isn't although taking into account it's quality it's not that expensive. i have about 1/3rd left, bought a couple of years ago and used on all SMD rework, not just reballs/reflows.

I have a lead and lead free profile, the lead free being a little hotter, haven't bothered with GFX cards as it's usually a failed GPU. I've done more TV mainboards than laptops recently with it.

[dicky96]

Re: Advice for a new BGA rework station owner please

OK mate I will order some of that flux. No point skimping for a few quid. And it sounds like 30ml should be enough for quite a lot of jobs.

It's nice to know I don't need lots of different profiles.

Re the Graphics cards I had heard in a lot of cases it is bad video ram or VRM but only one way to find out.

Which BGA machine are you using?

[diif]

Re: Advice for a new BGA rework station owner please

I have a Scotle IR or clone of one.

[dicky96]

Re: Advice for a new BGA rework station owner please

I've been looking at reballing kits and templates. I never realised there were so many different templates around! Jeez!! I assumed there may be like about a dozen different sorts covering 95% of chips.

This raises another batch of noob questions!

So what do I do? Buy one of these big sets of 850+ templates from some seller on ebay or aliexpress and hope I don't end up with 847 that I never use, or try to buy some more directly tailored to my intended use?

Or buy a 'starter' kit and add more as and when I need them.

The only problem I see with buying stencils individually when I need them is that it takes about a month to get here from china.

I'm beginning to suspect there are some rather odd people out there that actually 'collect' BGA stencils! Maybe in some bizzarre attempt to attract members of the opposite sex - 'come up to my room and I'll show you my stencils'

Also which reballing Stand should I buy - they seem to be loosely categorised as two sided ones like this
https://www.aliexpress.com/item/3273...chweb201603_55


and square ones like this
https://www.aliexpress.com/item/3295...chweb201603_55

Do all stencils fit any type of stand or do I need ones specific for the stand I buy?

Will I end up with a need for both types of Stand?

Is there some other sort of stand I should be using, i.e. non of the above?

So much to learn!!

Rich

[diif]

Re: Advice for a new BGA rework station owner please

The difference in the stencils is direct or indirect heating of the balls. Heating from the top with hot air or bottom of the IC.
There are also 80mm stencils and holders.

Watch some YouTube videos to get an idea of the different ways of using them.
Direct heat stencils are a bit messier IMO and it can be a little fiddly removing them.
I use this holder. https://www.aliexpress.com/item/32305092798.html

[dicky96]

Re: Advice for a new BGA rework station owner please

OK watched a few.

The first thing that strikes me is that using a stencil with solder paste looks easier than using one with solder balls. And I wouldn't need a whole range of different size balls

Is this a matter of personal preference and developing and learning your own method, or more a matter of different horses for different courses?

The second thing that strikes me is that putting the BGA on a hot metal plate to melt the balls/paste also seems the easiest way of doing that (and easier to control the heating and cooling)

[diif]

Re: Advice for a new BGA rework station owner please

I use balls with the stencils, haven't seen any videos of people using paste with them apart from an SMC on a mac as it was tiny. Balls are cheap.
I slide onto a hotplate for melting the balls.

[dicky96]

Re: Advice for a new BGA rework station owner please

https://www.youtube.com/watch?v=MqRT6KaMubk

That looks so much easier to me

[diif]

Re: Advice for a new BGA rework station owner please

If you read the description he's using solder paste instead of flux as it's less messy but balls are still added.

[dicky96]

Re: Advice for a new BGA rework station owner please

I didn't read that I was just looking at the pictures lol

What are the most common size solder balls I should buy first?

[diif]

Re: Advice for a new BGA rework station owner please

I have all of these sizes and have used them all apart from 0.76mm https://www.aliexpress.com/item/33028138659.htm

[dicky96]

Re: Advice for a new BGA rework station owner please

Thanks diif
I've ordered some of those as well

I thought I would get some solder paste too while i am at it

This MECHANIC XG-50SP seems popular
https://www.ebay.co.uk/itm/MECHANIC-...3ddc14cf0cb4e6

[diif]

Re: Advice for a new BGA rework station owner please

I've never seen a need for the paste, I've tried using it for repair a couple of times but it's just messy.

[m4a2t0t]

Re: Advice for a new BGA rework station owner please

My first rework station was some chinese POS like this one. I had NOTHING but problems with it and they did NOTHING to help. Their "help" was for me to pay to ship it to them and have them repair it. I would be out of my rework machine for weeks not making any money. In the end I had to replace all the IR heaters with better ones made by a german company and it did an OK job but I still have problems with it not heating the chips evenly.

I wanted to get the machine below, they start at $4k but you need a preheater so it's around $5k. NASA used this machine to do BGA work on all 3 Mars rovers. You know the ones that were working 10 years past their EOL. http://www.zeph.com/bgarework_statio...air_repair.htm

I don't even know if it's still good or whatever I just wish I had known that the machine I paid $3k for was a piece of crap and I would get next to no tech support or warranty. I don't do as much BGA work anymore but I would have 100% bought the more expensive machine, even if I had to save for months.

You need a stencil holder. There are a few styles but these are the styles I've worked with and do a good job. You should get both sizes in case a stencil is only available in a specific size.
https://www.ebay.com/itm/80x80-Pro-B...IAAOSwq7JT8zqC
https://www.ebay.com/itm/90-90mm-uni...IAAOSwq0pcu22M

You need stencils too but you're gonna need so many of them if youre working on GPUs and PC boards. I'd look into the popular GPUs and then buy them whenever you need them. The massive packs with like 100 stencils mostly suck and have garbage you never need. Look into getting a universal stencil for each ball size and different pitches. It useful so you don't have to wait a week to get the proper one. PROTIP: Properly store your stencils. The slightest bend and they are garbage. Store them together in a large stack or stacks. Keep them clean. The slighest amount of flux, even a small streak can cause nightmares when you've just dumped a few hundred spheres in the stencil. Clean both sides multiple times with a clean cotton pad and IPA or Acetone.

Solder spheres, all sizes. Never been a fan of using solder direct heat stencils with paste but you may like it. It's easier then having to have 10 different sphere sizes.

Soldering iron. If you don't already have one get a Blade bit for your iron. You can use a flat blade for quicker work but you'll need to get used to it.

Flux. It's mostly personal preference. I've always used ChipQuick flux for attaching balls to chips. It's sticky and holds the spheres in place well with no bubbling. It's works well for attaching chips to boards too.

Find a stack of boards you can use to desolder BGAs and resolder them. You'll need to get your machines heat profiles setup properly. Learn to clean the old solder pads without doing any damage and soldering new speheres to the chip. Every board is different (if you've done apple work then you've already dealt with the worst ). Xbox 360s (white ones) are easy to work on and test. You can reball CPU/GPU/RAM/SouthBridge. You can literally test the unit while its still in the boards jig, just plop the heat sinks on it and look for green lights then shut it off. This way you know the x-clamps are not adding pressure to a bad solder joint causing it to turn on but will fail after some heat cycles.

I would also like to point out that they station Diff posted shows it being a "universal reball station" but they only universal part is that it does 80 and 90 mm jigs, which is nice. It has a universal stencil and you only want to use them if you need to get it done ASAP. You see the areas without any balls on all the chips shown? Those areas will be filled with solder spheres, you need to use a tweezers to remove the solder balls stuck in those areas. You can try and bunch them up and hope one doesn't migrate into the areas with pads...Don't worry it will and you'll get to do it all over again. You can spend an hour or more trying to use a universal stencil, first you get the spheres in place then you spend twice the time cleaning up all the ones you don't need. Not every chip is all nice and square like the one shown. Universal stencils are normally a last resort.