3M 900AST - Manual

3M ™ Advanced Systems Tester 900AST Series 5 Use the [RFL] key to find the distance to a resistance fault between two conductors or a conductor and ground. This key is used for editing only. Use the [TDR] key to activate the Time Domain Reflectometer. Use the [Auto] key to activate automatic TDR trace...

3M ™ Advanced Systems Tester 900AST Series 6 TDR Setup The TDR features a setup function that allows you to select the type of Coaxial wire to be tested. From the TDR Menu, press the Setup key to enter the TDR Setup. Press the select key and the and arrow keys to highlight coaxial cable for wire typ...

3M ™ Advanced Systems Tester 900AST Series 7 TDR Test Modes Press the or keys to move to the desired mode. Press the key to accept the highlighted mode and start the measurement. Single Trace Use the TDR Single Trace mode to test a single coaxial wire or circuit.

3M ™ Advanced Systems Tester 900AST Series 8 Dual Trace Dual Trace is used to compare two coaxial circuits at the same time (usually a faulted and a good circuit). Connect the TDR test leads to the (Red and Black jacks) and connect the second TDR test lead set (Blue and Yellow jacks) to the referenc...

3M ™ Advanced Systems Tester 900AST Series 9 Use the and keys to highlight the desired stored result. Press the key to display the stored trace on the bottom of the TDR screen and the “live” trace on the top. You may move the cursor by using the and keys. The control settings for the stored trace ca...

3M ™ Advanced Systems Tester 900AST Series 10 Length allows you to set the distance (or span) from the left side of the screen to the right side. The left side of the screen is at the end of the BNC test lead and the right side is the farthest distance that can be displayed with the selected length ...

3M ™ Advanced Systems Tester 900AST Series 11 Press the key. The 900AST tester will display the Save Results screen as follows:Use the blue keys to enter an alphanumeric ID. The ID may have up to twelve digits. Whether a number or letter is entered depends on how many times the key is pressed. As an...

3M ™ Advanced Systems Tester 900AST Series 12 generally cause small upward peaks due to a change in impedance. To determine if an upward event is an impedance change or a main event fault you may go to the other end of the coaxial cable and disconnect it. Next, take a jumper and short the inner cond...

3M ™ Advanced Systems Tester 900AST Series 13 Short Circuit A short circuit (or zero-Ohm resistance fault) will show up as the lowest dip on the screen. You cannot see events past a short circuit Branch Circuit The beginning of the branch circuit will look like a small dip and the end of the branch ...

3M ™ Advanced Systems Tester 900AST Series 14 Connect the 900AST test leads to the coaxial conductor under test. Press the key to access the Soak test from the Resistance screen. Use the key to save the active resistance to the “Snap Shot” area. Rising resistance in the active box typically indicate...

3M ™ Advanced Systems Tester 900AST Series 15 To change the coaxial configuration go to the TDR function and press the Setup key. Use the and keys and the Blue numeric keys to enter the length of cable to analyze. Enter a length longer than the cable being tested but as close as possible to the tota...

3M ™ Advanced Systems Tester 900AST Series 16 In this case the low impedance anomaly at 24 inches is detected but not classified. The Auto TDR displays ‘????’ below the trace. Restoring the Aircraft After Testing/Troubleshooting Disconnect the 900AST TDR test cable from the aircraft wiring. Also, rem...