1. Short circuit and open circuit. MDA and ICT are good at finding short circuits - they have a needle bed to reach each electrical node, and the resistance between the dots can be measured to confirm the short circuit. The empty board tester uses a capacitance-to-ground technique, which is high in efficiency and speed if it is limited to empty boards. The flying probe test uses a capacitor technique and a proximity shorts technique; the former is not repeatable enough for most manufacturing facilities and lacks a good diagnosis. The best approximation test uses raw CAD data to confirm trace position, allowing the programmer to choose the maximum distance between test points. This provides a degree of control over the speed of the test; however, it should be recommended that the functional test equipment has a current-clamping or fold-back power supply to prevent damage to the board or test machine because A low impedance short circuit of the component may only be undetectable during the short circuit test.

2. Passive analog guarantees acceptable process quality by confirming that the UUT has been soldered to the board and components with the correct parameters are installed. This test is often performed with only a small number of WIPs, so the problem can be corrected before a large number of problematic products appear. The board is not powered, with selective passive or active guards to zero the current in the parallel current path. For the UUT and the surrounding guard position, an entrance to the needle bed is required.

3. The vision system provides device-level diagnostics. They use a golden board to compare it to a UUT without electrical testing. MDA provides electrical testing and component-level diagnostics, again compared to known good boards. ICT performs electrical testing, providing equipment-level diagnostics, comparing values and errors with BOM. The functional tester is tested according to the designer's specifications (usually called the sample golden board). If the functional test is thorough, it guarantees that the product can be shipped out. However, if the FPY is not particularly high, the manufacturer's price will be poor product, waste and expensive manual diagnosis and repair costs.

4. Active analog. ICTs, functional testers, and non-needle tests that power the board are good at finding bad active analog components. ICT and flying probe tests, while providing pin-level diagnostics, cannot measure some key manufacturer specifications (eg, bandwidth, input bias current, etc.). The functional tester measures the output characteristics without providing pin-level diagnostics. With the help of no vector technology, the visual system only confirms the existence of components. X-ray provides a diagnosis of weld quality.

5. Testing of digital and mixed-signal components. Visual, X-ray and MDA only diagnose open and short circuits. ICT uses a variety of methods, depending on components, circuitry, and accessibility. It can only use vectorless techniques for continuity, and when there are all entries, BS is used for continuity and component validation. Modeling a particular component by manual vector generation can be time consuming and may not be sufficient to cover the defect to determine the effect. A combination of continuous vectorless techniques and finite vector testing that guarantees component operation can be used to maximize coverage while limiting development time.

The functional system tests the circuit/module according to design specifications, but lacks foot/component level diagnostics that will reduce the cost of rework. In most cases, functional testing does not provide deep data that needs to be used for process improvement. Both function and ICT are programmed on-board flash, in-system programmable, and on-board memory components.

There is no one strategy that will or should be suitable for the manufacturer. When developing a test and process improvement strategy, countless variables must be considered.

The confirmation of the manufacturing defect spectrum should be factory specific and product specific. These data, if relevant and reliable, will reduce staff and scrap costs and increase customer confidence. Defect data should be collected, edited, and discussed at a meeting of the normal quality team. This data should also be used to develop a test strategy to find common preventable defects. These data should include factory and site failures, marked with dates. New product defects should be monitored, while mature products should be monitored to improve FPY and supplier quality. Defect data should be compared internally to short-term, along with other locations to improve overall quality. Data on weather conditions, personnel, suppliers, and line changes should be tracked as these are often potential quality factors.

Two important quality factors are related data collection and distribution experiments. A sensor's ability to collect data that will improve quality, and the ability of data managers to communicate data to the right group, affects current and future products. The definition of the correct data is determined by the facilities and products. The test machine acts as a sensor to monitor the process. An effective distributed test strategy finds process problems as close as possible to the root cause and reduces the amount of bad goods produced.