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Question about C6455BZTZ reball

Jin HAO
Prodigy 150 points

Hi, everyone.

I have a question about TMS320C6455BZTZ reball. When we soldered 6455 on our PCB, sometimes, not every pads were connected to the pcb well, so we need to remove this 6455 and reball it, then solder it again. The thing is: after we finished reball, then we found the DSP's 3.3V power supply pins and GND pins are short, not a 140K ohm anymore...

So, what should I do? How to reball this DSP? Which is the best way to reball this dsp?(We failed two times.....)

Thank you so much for your help

Best Regards,

Jin

  • 0
    TI__Guru* 84110 points

    It would appear that you have a very serious board manufacturing problem. This is something that would need to be solved within your board shop. You may want to contact the distributor who sold you the C6455 to see if they know of some reliable re-work companies in your area.

  • 0 in reply to RandyP
    TI__Guru* 84110 points

    Also, you may find the BGA Package Reference Guide helpful.

  • 0 in reply to RandyP
    Prodigy 150 points

    Hi, Randy

    Thank you for your advice.

    But, for some reason, we want to and must re-work this DSP by our self, we already bought some kinds of oven for soldering and reflow, and many

    metal lead-free balls for the reballing.

    Now, we can do Soldering and reflow well, but reball is not good. So, we want to know which is the right way to reball this DSP.

    By the way, we did reball in this way:
    1st: we clean this DSP pads, after then, we test the pin, and 3.3V Power supply and GND pin are good
    2nd: we put stencil quik BGA- Rework Stencils on this DSP, use FCT Assembly-NC650(cold-soldering) Leaded soldering tin to paste this pads
    3rd: we use brush to make all tin pasted on that pads are flat
    4th: we put the lead-free tin balls on that tin paste
    5th: we put this DSP into the oven, heated to 240C
    6th: we use alcohol to clean this DSP pads
    7th: after then, we found 3.3V and GND pins are short. But other pins look still OK.

    Thank you,

    Best Regards,

    Jin

  • 0 in reply to RandyP
    Prodigy 150 points

    Thank you. And before we did this re-work things, We had already read SPRU811 and followed its rules. But, after reball, it was failed....