Reconstructing A Pin On A Pin Grid Array Package

Before moving to land grid array (LGA) packaging whereby each pin on the substrate is just a copper pad, processors commonly used pin grid array (PGA) packaging, including the still highly relevant AMD AM4 socket. With PGA you get a pin soldered onto the copper pad which inserts into the ZIF socket, rather than a fragile pin on the mainboard side. Repairing a damaged PGA pin can be easy if just the pin broke off at the solder joint, or rough if the pad was destroyed, as in the case of this Pentium III CPU that [Bits und Bolts] recently tried to fix.

In the case of something like a ground pin or similarly unimportant pin you can ignore the damage, but in this case it concerned an important pin for this 1.2 GHz Tualatin PIII core, with the damage consisting of a well and truly destroyed pad. The first step to repair the damage is thus to try and rebuild the pad, which was done using solder mask and solder.

Although a PIII-era Celeron CPU is definitely not a high-value CPU, since they have so few and such large pins they do make for useful test subjects when it comes to PGA repair practicing. In this case the affected data pad and pin appears to have been repaired successfully, with it running overclocked to 1.6 GHz and crushing similarly or higher clocked Pentium 4 and AMD Athlon CPUs of the era.