[rescue] the cause of the dead cpus ?

[Dave McGuire]

On Thursday, May 15, 2003, at 11:12 AM, Curtis H. Wilbar Jr. wrote:
> If anyone was following the thread where I mention I ended up with a 
> lot
> of 10 "as is" (read "Dead") Slot 1 CPUs... I'm not sure but I have a 
> theory...
>
> Many of them now seem to (not for any extended duration) test ok now...
> the only difference is I'm using one of those metal clips to hold on 
> the
> heatsink rather than those cheap plastic "pin type" retainers.  I think
> it is putting pressure on the CPU differently (and possibly stronger) 
> by
> the heatsink and back casing.
>
> What I'm wondering is if the solder connections of the actual CPU (a
> BGA chip) to the slot 1 PCB is defective.  So, when I use the stronger
> clip to hold on the heatsink it is helping to compensate for bad
> solder connections of the BGA chip to the board....
>
> Does this sound realistic ?  Don't suppose anyone out there has the
> equipment necessary to reflow BGA soldered chips ? :-)
>
> I wonder how I can verify this theory ?

   Yes, this is certainly possible.  I have a reflow hotplate, but that 
will only be useful if there are no components on the back of the board 
and everything "meltable" (clips, etc) can be removed.  We can give it 
a shot if you want.

          -Dave

--
Dave McGuire                "They live deeply, these vagabonds."
St. Petersburg, FL                            -Goro