noob need tips about reballing

[ala_borbe]

helo ppl

lately ive been away a bit, but for a reason

ive got myself reballing station yaseen ir 1200++
its goood but im bad so i ask you to be my teachers

so far i managed to take chips off with ease (had to play a bit with temps but eventually i got it right)

learned to put balls back with use of stencils, so far so good... it took a little bit of practice but i managed it (98-99% balls in place, rest added by hand)

problem i face is when i need to put chip back...
how can i be sure that chip is back right and all balls are in place and soldered well?
when i start to heat chip it easily sits down like i saw in videos on youtube, but laptop wont strat, fan spins, no image... so i heat it up a bit and heat in more then before, nudge it a bit to be sure that all balls melted but after that still no image on screen

so any tips here? also, is there a way to test if vga or chipset worth reballing or is it even working...? what are max temps and how to know did i killed the chip?

tnx in advance
also any other tip would be great sin you have much more experience then me

[Pragmatiko]

Re: noob need tips about reballing

hi,
every ic chip have thermhal profile.
In principle you dont to go over 230° for 10/15 seconds.
You need to measure temperature with themocouple K type during solder process.

[passete]

Re: noob need tips about reballing

On my experience, even with 2 identical machines you will get different results !
Take a batch of about 30 dead mobos and start playing, you will pop corn, ram bleed, ... but this is the price to pay.
I do less reballs now, cause i get almost the same life span with a good Reflow, i mean a real good reflow and sometimes a reball.
You can also start by removing bga, clean mobo a buy the same bga ready to atach, less trouble.
Well, there is nothing like practice.

[ala_borbe]

Re: noob need tips about reballing

the challenge is on

[stj]

Re: noob need tips about reballing

a tip - buy solder balls from a pro company that actually tells you the exact metal-mix.
it matters when setting your temperatures.

[vinceroger69]

Re: noob need tips about reballing

Ive just been watching this guys videos he has some good ones on re balling etc
https://www.youtube.com/user/lufcfan2004/videos

[Djosla]

Re: noob need tips about reballing

We all had that problems...

The hardest part with reballing is removing the chip properly...Trust me...Point is to get to the right temperature to remove it without overhiting the ic or demaging the motherboard pins...puting back is easy...you didn`t have success probably because you overheated it while removing...
Lead-free solder melts around 218-225°C and leaded around 184°C so your profiles should be set according to that tamps...At first your board needs to be preheated properly...it needs to take temperature slowly and evenly...some board take temps very fast some very slow becouse of their thermal mass and component density... For daily boards i preheat them from around 190-200 for bottom heaters and i never go beyond 225°C...You will notice that bigger ic won`t remove easily even when your temps reaches 225°C...trick is not go higher with temps,that will damage your ic,but to heat it longer in 210-215°C range,so that ic takes temps properly...with smaller ic`s it is all easier...Also when you have epoxy around edges of the ic,or underfill...always remove it as much as you can before removing bga chip...way i do it is when board is in preheting state,i wait temps to be around 140-160 °C and than remove epoxy with sharp twizzers carefully...it ussualy fells of in one piece...underfill is nightmare...Because of this epoxy you will pull same pads of from motherboard,that`s like normal...but usually it`s dummy pins,so no worries...It`s hard but in time you will get it...One more tip...when you have big size motherboard...don`t let them flex or your ic`s will not lay down properly...you will have to put holder somewhere in the middle in order to board lay down straight and flet...it`s very important...

Now,a bout putting the ic back after reballing...it`s essentially same proces but just go slowly and don`t go over 200 °C...Pay attention on ic orientation...and lay down chip as precise as you can between the lines marked on the board...when balls melt it will reatach itself properly...

one more thing...When you got brand new ic`s put them in the oven on about 110 °C for few hours(some recomends 24h)to take out the moisture,or you will have popcorns even before 200 °C range...

Well i hope i helped...

[ala_borbe]

Re: noob need tips about reballing

first of all, thank you for your kind answers and tips

i perfected reflow process on my hot air gun and homemade preheater so most board lasts for 6 months or more (not that damn RS880, it fails hard) but i find it harder to use reballing machine cos of powerful heaters

first few chips popped right up, but those boards ware dead anyways
pads intact, epoxy is easy to clean when i heat it a bit, so no problem there

botom heater is ceramic, 2kw 5-6cm away from board, upper heater is IC
how far do i keep it form chip? usualy i put it 5-6cm from chip... is that good?

i did not know that about new chips, tnx, it will save me a lot of money

TNX a lot ppl for helping a newbie

[gcomputers]

Re: noob need tips about reballing

my first machine for reball is jovy re7500 and i did a lot of practice 2 month (i sleep only five hours at that time), to much chip popcorned, now i have ZM-R6200 with this no more problem its amazing machine ,so my advice is :
PRACTICE-PATIENCE... PRACTICE-PATIENCE.... PRACTICE-PATIENCE......
another choose from my practice i use solder balls lead free with that the chip work more long.

But for you, on the beginning it s best to practice with leaded solder balls because it s melts at 180°C-190°C.
For the new chip i bought some from aliexpres but most of him are fake not new not working chip, now i'm buying from SEE-IC store it's secure and very correct all chip are new and working.
For solder balls i bought from amtech but now i can find it more, i need too to find any PRO company ?

[samanthban]

Re: noob need tips about reballing

it was very hard at the beginning and waste lot of money for this . machine is zm-r590 its manual operation. very hard to control the temperature.my advice is to find your own way according to the machine.