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Model TR-5-400-QC Mechanical Advantage Fixture System


  • Up to 400 Test Points
  • Single-Action Lever Engagement
  • Low-Cost Replaceable Fixture Kits
  • No Vacuum or Air Source Needed
  • Top and Bottom Probing of SMT and Through-Hole
  • Compatible with TestJet Technology
  • Easy-to-Change Fixtures

CheckSum TR-5-400-QC Mechanical Advantage Fixture System Overview

The CheckSum Model TR-5-400-QC Mechanical Bed-of-Nails Fixture System is designed for test fixturing of assemblies with up to 400 test points. The Fixture System consists of a reusable Fixture Press that is used in conjunction with low-cost, easily interchanged Fixture Kits. The TR-5-400-QC can also be used as a basis for your custom standalone functional fixturing. The inside has room for mounting circuit assemblies, and the aluminum back-panel can be machined for connector cutouts.

To operate the fixture, the operator places the unit-under-test (UUT) onto the guide pins in the fixture. The operator then turns the lever-arm to actuate the probes. Turning the lever-arm closes the lid and compresses the probes through a linear mechanical advantage mechanism. When the operator rotates the lever-arm, the top plate moves forward and down to engage the UUT. The lever-arm can be moved to the right or left side of the system depending on operator preference.

The CheckSum TR-5-400-QC Fixture System can accommodate UUTs with probe areas of up to 11.75 x 8.50 inches and with up to 400 test points.

The TR-5-400-QC Fixture System is shared by all of your UUTs. Since the TR-5-400-QC has linear travel, it can accommodate probing on both top and bottom with either standard probes or TestJet Technology probes.

For each individual UUT, a low-cost KIT600-QC is customized by drilling and wiring. Installing Fixture Kits in the Fixture Press is done very quickly. This process is simplified because there are no cables to change and no tools are required, the top and bottom simply snap into place. A bottom pan protects the wiring and pins in the removable Fixture Kits. Using the storage handles, the top pressure plate can be attached to the probe plate when the fixture is not in use.


Options for the TR-5-400-QC are:

  • FIX-200P-RBPM 200-point Receiver blocks with wiring to back-panel connectors
  • Front-panel keypad
Note: At least one 200-point receiver block (FIX-200P-RBPM) must be ordered with each TR-5-400-QC fixture press.

Signals are transferred from the fixture kit to the fixture press back-panel connectors by low-cost 200-point wiring blocks (FIX-200P-WB) in each fixture kit and 200-point receiver blocks (FIX-200P-RBPM) mounted in the fixture press. The TR-5-400-QC can accept up to three receiver blocks for connecting up to 600 signals into the fixture kit. The TR-5-400-QC is designed to compress a maximum of 400 spring probes in the fixture kit.

Four standard 50-pin back-panel connectors are included as part of each FIX-200P-RBPM receiver block.

Model TR-5-400-QC Fixture Kit

The TR-5-400-QC uses the KIT600-QC Fixture Kit. The KIT600-QC Fixture Kit includes:

  • Probe-plate with bottom pan
  • Two shipping/storage handles
  • Clear polycarbonate top pressure plate
  • Ten pressure rods (MA-ROD)

At least one 200-point wiring block (FIX-200P-WB) must be ordered with the KIT600-QC. The KIT600-QC can accept up to three wiring blocks for connecting up to 600 signals into the fixture kit.

Customizing Your Fixture

Customizing the fixture for your UUT can be done by CheckSum or by your local fixture contractor. If the necessary drilling and wiring equipment is available, it can also be done in-house. If you are doing your own custom fixturing, you will need to add:

  • UUT guide pins
  • Spring probes and receptacles
  • Internal wiring
  • 200-Point Wiring Blocks (FIX-200P-WB)
  • Pressure rods (MA-ROD and/or MA-ROD-T) as necessary (one is used for each 10-25 test points)

Mechanical bed-of-nails fixtures require less expertise to customize than vacuum fixtures since vacuum gaskets are not required. Contact the CheckSum fixture group for more information and competitive custom fixturing and test programming quotes.

Model TR-5-400-QC Specifications

Weight (Press)
Approximately 35 lbs. (shipping wt. 45 lbs.)
Weight (Kit)
Approximately 10 lbs. (shipping wt. 15 lbs.)
Overall Size
20"W x 24"D x 13"H (51 cm x 61 cm x 33 cm)
Usable Size
Probe Area 11.75"W x 8.50"D (29.85 cm x 21.6 cm)
Inside Depth
Inside bottom pan 2.44" (6.2 cm)
UUT Height
Probe plate to top pressure plate 1.525" (3.8735 cm)
Probe Plate
G-10/FR-4 0.375" (0.9525 cm)
Top Plate
Polycarbonate 0.50" (1.27 cm)
Linear Travel
0.50" (1.27 cm)
Probe Count
Up to 400
Interface Signals
Up to 600
Back-Panel Connectors
Standard 50-pin header (25x2, 0.1 inch on-center, male/pins)
Keypad connector - DB25F
Ground Input - banana jack
90-day limited parts/labor

Download Model TR-5-400-QC Data Sheet(USA 2 pages) PDF

Download Model TR-5-400-QC Data Sheet (International 2 pages) PDF

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TR-5-400-QC Ready
Model TR-5-400-QC with UUT mounted on a fixture kit

TR-5-400-QC Testing
Model TR-5-400-QC actuated and ready to test






Front Panel
The TR-5-400-FP front-panel keypad option provides an operator input keypad and a set of LEDs that can indicate Power, Fail, Busy, and Pass.

Back Panel
Model TR-5-400-QC back panel connectors



KIT 600-QC Fixture Kit