As some of you may know I recently bought a BGA machine and I have not had much trouble removing chips with it but this one has me stumped. I feel like taking my old heat gun to it and blasting it off at 1000C! It is a southbridge chip (AF82801IBM) on a HP CQ42. I removed the clear epoxy/glue that was at each corner and thought that was all of it. Could there be some under the chip? I poked under it with a scalpel but could not feel any more. My profile on the BGA goes up to 230C but the chip won't nudge or budge. I would like to hear some suggestions. I read where some people try to get liquid flux under the chip - is that how you guys do it with a stubborn chip? Grateful for any suggestions.
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Re: Can't get BGA chip off is it glue?
Probably 230 isn't enough for the chip. What kind of BGA machine do you have?
Sometimes I've to go up to 245-250. -
Re: Can't get BGA chip off is it glue?
Hi
I have a ZM-R5860C and here is the profile i use :
PREHAT 1 PREHEAT 2 ACTIVATION SOLDERING 1 SOLDERING 2 DOWN
TOP 165 185 210 235 255
TIME 50 30 30 40 45
BOTTOM 165 190 215 240 255
TIME 50 30 30 40 60
SLOPE 3 3 3 3 3
IR 190
SOUTH BRIDGE/ LEAD FREE
all machine are a little different and your area also.
Techman1025Comment
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Re: Can't get BGA chip off is it glue?
At 230-235 lead-free solder should be liquid. If not, your thermocouples are reading wrong.
I use the following trick to lift stubborn chips: After 10-15 seconds at 230C or above, if it doesn't move, i take my sharp tweezers, place one tip under the chip and try to lever it slightly. Just enough to see that it has lifted a couple of mm. Then it comes out using the vacuum pen no problem.
A working TV? How boring!Originally posted by PeteS in CAComment
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Re: Can't get BGA chip off is it glue?
I think what ever liquid or flux you are using it has not reached center of bga chip.try pressing corner all 4 sides when melts.than move it & lift it .
all the bestComment
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Re: Can't get BGA chip off is it glue?
Thanks for the suggestions. The BGA machine is a scottle IR6000. I managed to get it off after The Unique advised his hold times at 230C and I thought maybe this timing is my problem. I extended my hold time at this temp from 25 sec to 40 sec and the chip came off without too much trouble. The chip looks OK and is not popcorned, However, because the chip has been through 4 cycles of trying to get it off I think I'll ditch this chip and buy a new one.Last edited by sparker1; 10-05-2014, 11:27 PM.Comment
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Re: Can't get BGA chip off is it glue?
this little beast some times fail very soon but sometimes even popcorned ic worksComment
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Re: Can't get BGA chip off is it glue?
im fighting today with my full ir machine, as i have had some problem with old mainboard and chip. some bga just popcorn very easy and on some mainboard or mxm vga i was not able to lift bga even at 225° on top.
after some try i discovered that putting a high bottom temperature , the top lift much easyer...
for example when i had bottom at 200° and top at 225° some bga wont lift easy.
now if i have 240° on bottom, i can lift bga when top is 190°, so maybe it's just an adjust of bottom and top temperature to make the perfect lift.
now i have to balance those temperature to get a good work.
ofcorse you need to have best thermocouple. i use original omega. my rework station is a jetronix eco.Comment
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Re: Can't get BGA chip off is it glue?
maybe you didn't flux well the chip .. if the chip don't have enough flux between chip and board you might fell it more hard to remove .. but attention also to the distance between the bottom and upper heater your board. usually bottom heater(hot air) is about 1cm from board. and upper heater , is around the same . and after stage 5 (bottom 250) upper (240) is welded or unwelded with no problem. but attention to something each region have different kind of air (humidity etc etc and all this factores counts a lot
my advise always minimum of 20 degrees diference on bottom (in this case , for ex , bottom 250 .. upper 230 don't give more heat on the chip when you can give it on the bottom part of the board.
Last edited by highpulse; 10-06-2014, 04:13 PM.Comment
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Re: Can't get BGA chip off is it glue?
Thanks Highpulse and DellXPS15, Do you use a bottom thermocouple on the MB (I use the one on my DMM)? I get the bottom of the MB to 150-160C but the bottom PID controller reading is 280C. Is this the temp you're referring to? I have had some disasters in this process and it is just when I think I can have a try at a good MB. In one instance the top thermocouple came loose and fell off the MB. I didn't notice and couldn't fathom why the top heater was racing away to hell temperatures. Needless to say that by the time I realised what was wrong it was too late. On another ocassion I forgot to remove the cmos battery which was nearby to the chip I was removing. The damn thing exploded! I guess it's all part of the learning curve but mine seems extra long.Last edited by sparker1; 10-06-2014, 04:51 PM.Comment
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Re: Can't get BGA chip off is it glue?
well my advise to you is to tune up your bag machine , get a good thermocouple wire for bottom and upper heater , put the thermocouple glue to the board on both parts . one on the bottom , fix it with kapton tape and make sure the tip of the thermocouple is touching the board and the upper thermocouple make it touch the die on the center of the chip . for unleaded chip i advise bottom max 255 . and on the DIE of the chip 235 is more than enough , but follow the KC thermocouple reading not your machines thermocouple. when you reach does temp on your thermocouple , chek which are the real tempo showing on your machine , for you can be precise . do this with a spare board (not a client board :P) my R490 for ex . the thermocouple are inside the mechanism before the nozzle .. so for lifting unleaded chip i use in last stage of my profile , 260 bottom , 245 upper heater and i remove them always .. but don't forget to use flux under the chip or else will be hard to remove. advise to put flux or you have a seringe with a good tip or with a small brush , just put flux on the 4 sides.Comment
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Re: Can't get BGA chip off is it glue?
Thanks for advice.Comment
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Re: Can't get BGA chip off is it glue?
flux do it's job. only board i have had some problem in lifting was mxm video card. some of that wont just separate like others.
ofcourse i put some kingbo flux on 4 side of chip.
using the more heat at bottom did a good job. check if your achi 6000 has good power on the bottom.Comment
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Re: Can't get BGA chip off is it glue?
I agree with the above, also try to turn the bottom temperature higher. The chips should be at 230C for no longer than 25-30 seconds, otherwise you run the risk of damaging (popcorning) the substrate.A working TV? How boring!Originally posted by PeteS in CAComment
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Re: Can't get BGA chip off is it glue?
I just want to clarify something-the temperature of the bottom of the board. I have it reach 150C (thermocouple reading not PID reading which is 280C) before the top heater starts. Are you guys recommending the bottom temp should reach over 200C? I think some components on the bottom would fall off if it was higher.Comment
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Re: Can't get BGA chip off is it glue?
try this steps (the same i use)
HOT PLATES ( they have the temp of 200 on all stages
1 stage , upper heat 160 degrees (90 seconds)
1 stage bottom heat 160 degrees )90 seconds)
2 stage upper heat 195 degrees (40 sec)
2 stage bottom heat 205 degrees)(40sec)
3 stage upper heat 220 degrees (30sec)
3 stage bottom heat 240 degrees (30sec)
final stage peak time upper heat 245 (20 sec)
final stage peak time bottom heat 255 (20 sec)
on final stage in the moment in start usually im near the machine to chek manually if there is chip movement to avoid unnecessary heat for the chip , once you notice it moving stop to cool down but before stoping remove the chip .
attention that this is the temps reading by honton (usually there is a diference about 10 to 15 degrees on the board .
i hope it help you out to make so curves.
about the bottom heat since the board after 2006 all use silver on the solder , they will only start melting at 217 degrees so this is something you don't need to worry . i don't like IR because its not something simple like it should be .
you can work only bottom heat until 170 degrees , then on the next stage bottom drop to 215 , and you can activate ir for 225 degrees and stay near and touch softly the chip to see if you notice movement (attention it will not happen right after the IR is turned ON , you must chek at each 5 sec once you see movement , remove chip and turn off IR .
i hope it will help you out .Comment
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Re: Can't get BGA chip off is it glue?
Hi,
I have a ZM-5860 se bga machin and i use these setting temperature for some chips that didn't disoldered normally:
1- 160 'C 30 sec
2- 190 'C 30 sec
3- 220 'C 30 sec
4- 240 'C 30 sec
5- 260 'C 30 sec
for top and bottom ,and ir set to 190
also check bottom nuzle distance (1 cm is good) and use good flux
it is magic setting for me
goodluckLast edited by tiak; 10-07-2014, 05:53 PM.Comment
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Re: Can't get BGA chip off is it glue?
After all the comments and help I have decided to increase the bottom heater preheat temperature from my 150 to 180C. I've read where the bottom heater should do most of the work anyhow. I'll see how that goes and adjust up if necessary. Thanks.Comment
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Re: Can't get BGA chip off is it glue?
make many practice.... im still fighting to dont make board bend and chip not popcorning.
ps: is it better to have top- bottom temperature as near as possible or just get for example 240 bottom and 210 top for chip lift ?Comment
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Re: Can't get BGA chip off is it glue?
to aviod board bending , you msu have a good pre heat time 160 degrees with be good for more than 60 second , i use 90 , my boards are always really straight and not bended at all
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