Operation Broken Pin

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Pinned Down in Silicon Valley

The Problem

Broken pin on a pin grid array.

While working with an extremely expensive prototype component, a tech broke off one of the pins at the base near the component body. The shoulder of the pin is approximately twice the diameter of the main pin body and approximately .50" (12.7 mm) in length. 

Any repair would have to endure the mechanical stress of insertion plus the thermal stress of soldering temperatures when the component was soldered back into the circuit board.

The Solution

Broken pin repaired by soldering on a specially modified new pin.

A commercially available pin with the same diameter and gold plating as the original pin, but with a larger base was selected. The key feature was the wide base because the repair required the hollowing out the base to fit over the stub of the broken pin remaining on the component body.

The center of the pin base was machied to a depth of .050” (1.27 mm) leaving a thin wall around the circumference of the pin base. This machined opening was tinned with high temperature solder. The stub remaining on the component was also tinned with high temperature solder. 

A support fixture was fabricated by drilling clearance holes in a piece of laminate following the pin pattern. The new pin was then soldered onto the component using a hot plate, flux, high temperature solder and a hot air rework system. 

The final step was to add a small fillet of high strength epoxy around the rework area.

Several members of the Circuit Technology Center team contributed to this feature story.