Dual stage vacuum chamber with full circuit board support

摘要

A dual-stage fixture for a circuit tester includes a slide plate that can be slid between at least a first position and a second position. In the first position, an upper stripper plate is spring-loaded, and a full set of test probes, including both long-stroke and short-stroke probes, can contact the circuit board or UUT (unit under test). In the second position, the upper stripper plate becomes fixed in position, and only the long-stroke probes can contact the circuit board. The fixed positioning of the upper stripper plate prevents the short-stroke probes from contacting the circuit board even when there is unbalanced loading of probe pressure between the top and bottom of the circuit board, thereby preventing transient signals from interfering with testing. In addition, a vacuum is applied in this position during a non-powered test.

主权项

1. A circuit tester for testing a circuit board or UUT (unit under test), the circuit tester comprising:
a housing having first and second parts capable of moving toward and away from each other a push plate mounted; a bottom probe plate mounted proximate the second part of the housing and having a first set of first test probes having a first length and a second set of second test probes having a second length than the first length; a jumper plate; at least one rigid support members mounting the jumper plate to the push plate, the at least one rigid support member connected to the jumper plate via a respective bias member; a plurality of resilient members; and a first slide plate selectively movable between a first by-pass position and a second blocking position to determine which probes will reach the UUT, the first slide plate having a surface that contacts the rigid support members when the first slide plate is in the first position, the first slide plate having at least one aperture formed and sized to receive a support member when generally aligned to pass therewith therein for receiving the rigid support members when the first slide plate is in the second position to allow the support member to pass therethrough; wherein, when the first slide plate is in the first position, the first test probes and the second test probes contact the UUT and, when the first slide plate is in the second position, only the first test probes contact the UUT when the support member are misaligned and cannot pass through the aperture so that they cannot contact the UUT.