By Ram Y.Gopal

The thesis presents the work done towards the design and development of a cost effective bare printed circuit board diagnostic system. The design comprises of manual test fixture, test point electronic system, IBM-PC interface and the diagnostic software. The system has been developed with a capability of detecting the most common faults viz. shorts and opens occurring on a bare PCB during the manufacturing process.

The primary input of the diagnostic system is the original; CAD netlist to whose circuit design specifications the PCB has been manufactured. Given the original CAD netlist, the system proceeds to capture the netlist of the specimen bare board with help of the test fixture assembly and the associated electronic circuitry. These hardware modules housed within a cabinet have been interfaced to the personal computer with an 8-bit add-on card designed employing Industry Standard Architecture.

Starting with the UNIX pattern matching tool awk as a model, a pattern-action based CAD netlist processing environment has been built to diagnose the faults on a specimen bare board. The proposed netlist processing algorithm compares the captured netlist with the original netlist for diagnosing the network interconnections on the bare board as shorts or opens. An elegant text based interface has also been developed to guide the end user/customer through the diagnostic procedure.

The hardware and software developed for the bare PCB diagnostic system have been validated by diagnosing a specimen bare board. The diagnosis of the specimen bare board has been carried out in accordance with the requirements and guidelines of Institute for Interconnecting and Packaging Electronic Circuits (IPC). Faults have been simulated on the specimen and detected for verifying functionality of the system.

A prototype of Bare PCB Diagnostic system has been developed with a view to commercialise the product.