The Tektronix TR 210 is an accessory to an oscilloscope which allows power off troubleshooting of electronic circuits by using the technique of Analog Signature Analysis. This signature shows the V/I characteristics of an electronic device which when compared with a known good device, can assist in locating faulty components of a circuit without applying power to the board under test. This technique of troubleshooting simply involves the visual comparison of circuit signatures which can assist in isolating circuit failures due to opens, shorts, device leakage, ESD damage, power supply over-voltage and transients. Analog Signature Analysis or ASA is a unique, power-off troubleshooting technique. It uses an alternating current (AC) sinewave stimulus to show the current (I) vs. voltage (V) characteristic of an unpowered component on a CRT. The IV characteristic is called an analog signature and each pin of a component can have a unique signature. When components fail, their signatures change so troubleshooting using ASA is simply a matter of finding the defective component by analyzing its signature. You can compare signatures of suspect components to signatures of known-good components. Test current applied across a component is limited. When used carefully, this technique is non-destructive and does not damage any components. ASA has many advantages as a proven, fast, and effective troubleshooting technique. You can: ■ Troubleshoot circuitry that cannot be powered up due to a shorted condition. ■ Troubleshoot in a qualitative mode, allowing you to see physical problems with a suspect component. ■ Compare device characteristics with known types for better matching. ■ Eliminate risk of accidental shorting across other points during POWER ON testing which could further damage the component or other components on the board. ■ Minimize the risk of shock hazard since the ASA troubleshooting approach requires no power applied to the circuitry. ■ Perform preventative maintenance by seeing flaws in components that could possibly lead to untimely failures. ■ Look at replacement components before they are installed in circuitry to reduce the risk of installing defective ones.