• Mechanical Bed-of-Nails Fixturing
  • Up to 150 Test Points for Standard Kits
  • Up to 500 Test Points with the TR-5-1612-C Mechanical-Advantage Kit
  • No Need for Vacuum Source, Gasketing or Receiver Assembly
  • Easily Customized
  • Low Cost for dedicated fixtures


  • Low Pin Count Circuit Assemblies
  • Small Bare Boards

Product Details

The fixture kits are mechanically operated and therefore do not require a vacuum pump or fixture receiver. A transparent top plate with pressure rods presses the unit-under-test (UUT) down onto the probes, then locks into place with a sturdy latch. Mechanical bed-of-nails fixtures require less expertise to customize than vacuum fixtures since vacuum gasketing is not required. In most cases, users with the facilities to do precise drilling can customize their own mechanical fixtures. This process entails installation of guide pins, drilling for spring probe receptacles, wire-wrapping inside the fixture from the bottom of the spring probe receptacles to the back panel connectors, then installation of pressure rods in the top panel.

Models and Specifications

  • TR-5-812 is 20.3 x 30.5 cm (8 x 12 in) overall; accommodates boards up to 15.24 x 15.24 cm) (6 x 6 in)
  • TR-5-1216 is 30.5 x 40.6 cm (12 x 16 in) overall; accommodates boards up to 25.4 x 25.4 cm (10 x 10 in)
  • TR-5-1620 is 40.6 x 50.8 cm (16 x 20 in) overall; accommodates boards up to 35.6 x 35.6 cm (14 x 14 in)
  • TR-5-1612-C is 40.6 x 30.5 cm (16 x 12 in) overall; accommodates boards up to 34.3 x 21.6 cm (13.5 x 8.5 in)

The test fixtures include two 50-pin back panel connectors (with cutouts for up to four additional connectors) that can directly connect to the ribbon cables provided with CheckSum Test Systems. Some of the connectors can be used to route functional test signals. Internal to the fixture, the back panel connectors have wire-wrap posts. To ease wiring of the fixture, the probe plate hinges up from the fixture frame. This allows easier wiring and fixture debugging. Also, the bottom and each side can be individually removed for access to the wiring. The Model TR-5 fixture kit top-plate hinges have a counter-balance spring to allow it to be positioned open, closed, or to any position in-between. Side-handle grips allow units to be easily handled. Ten pressure rods that press the UUT onto the spring probes are included with each Fixture Kit.

When a Model TR-5 fixture kit is ordered in conjunction with a CheckSum Test System, the system is shipped with a ground wire for connection between the system controller and fixture. A probe for automatically identifying test points is also included in this case.

Note on Quick Change test fixture systems: For a quick-change fixture kit system for assemblies with up to 400 test points, see the Model TR-5-400-QC.