Surface mount package fault detection apparatus
View Patent ↗A fault detection apparatus for surface mount packages is provided. The apparatus can include a retainer for releasably securing a circuit board such as a printed circuit board having an electrical component mounted thereon via a ball grid array surface mount package. When mounted within the apparatus, a test signal is applied to the electrical component. The apparatus includes a mechanical actuator, such as a solenoid, for applying a reciprocating force to the circuit board. The reciprocating force can disturb a defect in the ball grid array manifesting as a mechanically unreliable connection at one of the balls where an electrically intermittent connection is occurring. By disturbing the mechanically unreliable connection, the electrically intermittent connection can be caused to fail altogether and thereby reveal the defect as a test signal is carried through the printed circuit board.
1. A fault detection apparatus for detecting a fault in a surface mount package of a circuit board assembly; said circuit board assembly comprising an electrical component mounted to a surface of a circuit board via said surface mount package; said apparatus comprising:
a retainer for releasably securing said circuit board assembly;
at least one solenoid comprising a core portion and a rod; said rod movable between a retracted position and an extended position; said rod being disposed in relation to said circuit board such that changing between said positions causes deflections in said circuit board; said rod disposed beneath said surface mount package;
said at least one solenoid for applying a mechanical force to said circuit board when said circuit board assembly is secured within said retainer and while a test signal is passed through said circuit board; said mechanical force for disturbing a mechanical defect in said surface mount package to thereby reveal, using results from said test signal, an electrically intermittent connection in said surface mount package.
2. The fault detection apparatus of claim 1 wherein said surface mount package is a ball grid array.
3. The fault detection apparatus of claim 1 wherein said rod includes a cap made from an Electrostatic Compliant material.
4. The fault detection apparatus of claim 1 further comprising a signal generator for applying a varying signal to said solenoid to cause said rod to cycle between said positions.
5. The fault detection apparatus of claim 4 wherein said signal generator operates at a frequency of between about 120 and 170 Hz.
6. The fault detection apparatus of claim 4 wherein said signal generator operates at a frequency of between about 130 and 160 Hz.
7. The fault detection apparatus of claim 4 wherein said signal generator operates at a frequency of about 150 Hz.
8. The fault detection apparatus of claim 1 wherein said mechanical actuator includes a plurality of solenoids.
9. The fault detection apparatus of claim 1 wherein said circuit board assembly includes a plurality of electrical components mounted via a respective surface mount package.
10. The fault detection apparatus of claim 9 further comprising a plurality of mechanical actuators respective to one or more of said electrical components.
11. The fault detection apparatus of claim 1 wherein said retainer includes a base plate.
12. A fault detection apparatus for detecting a fault in a surface mount package of a circuit board assembly; said circuit board assembly comprising an electrical component mounted to a surface of a circuit board via said surface mount package; said apparatus comprising:
a retainer for releasably securing said circuit board assembly; said retainer including a base plate; said base plate including a plurality of mounting-posts projecting from said base-plate that align with a corresponding plurality of mounting-holes in said circuit board; and
a mechanical actuator for applying a mechanical force to said circuit board when said circuit board assembly is secured within said retainer and while a test signal is passed through said circuit board; said mechanical force for disturbing a mechanical defect in said surface mount package to thereby reveal, using results from said test signal, an electrically intermittent connection in said surface mount package.
13. The fault detection apparatus of claim 12 wherein said mounting posts include a male thread that projects above said mounting-holes and wherein said retainer further includes a plurality of crown nuts with female threads complementary to said male threads; said crown nuts for securing said circuit board to said mounting posts.
14. The fault detection apparatus of claim 12 wherein said retainer further comprises a clamp for applying a force to said circuit board and thereby secure said circuit board between said clamp and said base plate.
15. A method for detecting for detecting a fault in a surface mount package of a circuit board assembly; said circuit board assembly comprising an electrical component mounted to a surface of a circuit board via said surface mount package; said method comprising:
securing said circuit board assembly within a retainer;
applying a test signal through said circuit board;
applying a mechanical force to said circuit board for disturbing any mechanical defects in said surface mount package; said mechanical force being applied by at least one solenoid comprising a core portion and a rod; said rod movable between a retracted position and an extended position; said rod being disposed in relation to said circuit board such that changing between said positions causes deflections in said circuit board; said rod disposed beneath said surface mount package;
and,
using results from said test signal, revealing an electrically intermittent connection in said surface mount package as a result of said step of applying said mechanical force.