Test equipment for the Line Replaceable Unit (LRU) to removed printed circuit boards and subassemblies have been designed and manufactured for systems from engines to autopilots to radars. The testing, troubleshooting, and repairing today’s avionics equipment is becoming more complex. In addition, some repair stations are now receiving circuit cards and sub-assemblies removed from LRUs for repair. Failed circuit cards and subassemblies found during an Automated Test require a separate test set/stand for their troubleshooting and repair.
Since this test equipment has some or many printed circuit boards, designing them is beyond the capability of many repair stations. The design and layout of the printed circuit boards are done in house. Factory trained and certified in OrCAD Capture and PCB Editor software. The front panels are designed on a CAD/CAM program and manufactured on a CNC machine. Various panel configurations with color selections and text sizes/fonts are possible to satisfy customer’s desires.
After meeting and consultation with the repair station customer and determining their requirements. Research through the maintenance manual of unit going to be tested is done to determine the scope and degree of necessary testing requirements. I work with the company’s program manager on the project and advise him of my findings and recommendations before the design phase. The company’s input and eventual approval will ensure the equipment is built to their requirements. Panels are made to the customer’s desires and specific needs such as the size and positioning of items such as meters, switches, connectors, and placement of the company’s logo.
Many projects involve interfacing a customer’s associated test equipment such as their ARINC 429 simulators into the test panel. I have extensive experience with programming ARINC 429 tests using software such as Co-Pilot by Ballard/Astronics, Mystic by Excalibur and Vortex by RTX Systems. Experienced with interface programming of GPIB controlled test equipment. After the test equipment is manufactured and tested, it is calibrated. Usually, a test LRU is provided by the customer for use in testing all the parameters and functions. The equipment is provided with the schematics and drawings. The test procedures to run the unit-under-test (UUT) are written and provided to the customer. Also, will provide assistance to repair stations and their DER (Designated Engineering Representative) when needed to develop their own FAA approved repair authorizations. Upon completion the equipment is delivered to the customer and its use demonstrated along with the training of their technicians.
The Automated Test Equipment (ATE) gives a PASS or FAIL test result of the Line Replaceable Unit (LRU). In the case of a FAIL result, it directs the technician to replace a subassembly such as a circuit board or module. The repair of these subassemblies is accomplished outside the LRU and usually involves additional testing equipment to input the necessary voltages and signals. TMW Enterprises engineers, designs, and manufactures items such as circuit board/module testers and extender boards for troubleshooting printed circuit boards outside of the UUT.
Other capabilities are the re-design or reverse-engineering of obsolete, burnt, damaged, or missing printed circuit boards. Printed circuit boards may not be available due to manufacturers termination of supporting products after several years, a company merger, or simply the manufacturer is no longer in business. This makes obtaining a replacement printed circuit board very difficult if not impossible. If the schematics and parts list are available the printed circuit board can be re-designed and manufactured to an identical form, fit, and function as the original.
Additional capability is the VSWR testing of radar altimeter and X-Band radar antennas using the HP8757D Network Analyzer and HP 83752A Synthesized Sweep Generator.