Arrow [REPAIR TIPS] Nokia BB5 Stacked chip, RAP swap, flash change.

shashidawan

Hello,
this is actually an old tips, but seems not so many people know how to it.
hope this will be useful for all who need it.


How to rework on stacked chip:

http://oi48.tinypic.com/efnel5.jpg


1st:
put big nozzle on hot air to lift up. apply flux as needed. use good quality flux.
Lukey 701: temp 380, maximum air flow.
Do it gently and don't be so hurry. About 2 minutes, leadfree material will be melted.

http://oi50.tinypic.com/euj8kh.jpg

and after sometimes, you will be an expert, you can do rap and flash chip lift up together all in one step:


http://a3.sphotos.ak.fbcdn.net/hphot..._3605094_n.jpg

clean all leadfree materials on pcb and on chip. this should be done perfectly,
in order to get perfectly joint contact on our next reballing with leaded tin paste.

there is nothing special when reballing on lower part (rap to pcb side).

2nd:
do reball on flash chip. pay attention on the result of tin balls we made after reballing it.
if it too small, this will not reach to joint contact on rap upper solder side. will be hang up by rap core.


http://oi45.tinypic.com/wvdb1l.jpg

do it two or three times reballing steps, to get the correct ball size.
examine the result, see if the size is correct as needed. apply flux, reheat once more, this will make the balls self-positioning correctly.

http://oi45.tinypic.com/rkpkpw.jpg


Time to put it on rap. again, use big nozzle on hot air. lower temp, lower air flow. because now we used leaded tin paste.

http://oi50.tinypic.com/ppsv6.jpg

and that is all.

Software side: apart from RPL calculation by Nokia server
- Flash change SL3: phone should be able to be powered on local / test mode before flash change. you will need to backup it's rpl+simlock.
# backup all certificate, replace flash chip, reflash, restore all certificate do rfbb tune, dcc if needed.

- Flash change all BB5 up to SL2: phone should be able to be booted and readed at least NPC part certicate,
since rebuild simlock and other certificates now is easy on these phones.
# backup at least NPC certificate, replace flash chip, reflash, restore NPC, rebuild certificate and do rfbb tune, dcc if needed.

RAP swap up to SL2: same as above, you need at least NPC certificate for this rap. need the same way as flash change above.
# before moving into new board, make sure you have at least NPC certificate.
further steps, same as flash swap above.

RAP swap SL3: you will need full certificate backup before move this chip into another board.
#backup full certificate, move rap to new board, reflash, restore all backup.