Agilent Technologies 6681A, 6684A, 6680A, 6683A Troubleshooting Charts, Troubleshooting Test Points

Troubleshooting Charts

Figure 3-1 gives overall troubleshooting procedures to isolate the fault to a circuit board or particular circuit (see Figure

3-20 for the location of the circuit boards). These procedures include the use of power-on selftest (Table 3-2) and signature analysis techniques (Table 3-5 through Table 3-7). Some results of Figure 3-1 lead to more detailed troubleshooting charts that guide you to specific components. The troubleshooting charts are organized as follows:

Chart	Trouble or Circuit
Figure 3-1	Overall procedure checks selftest errors, calibration errors, ac input circuit, fan, readback
	circuits, A10 Control Board, GPIB cable, digital port, serial link, rotary controls, current
	amplifier.
Figure 3-2	No display (from Figure 3-1).
Figure 3-3	OV circuit not firing (from Figure 3-1).
Figure 3-4	OV circuit is on at turn on (from Figure 3-1).
Figure 3-5	Output level is held low (from Figure 3-1).
Figure 3-6	Output level is held high (from Figure 3-1).
Figure 3-7	DAC circuits (from Figure 3-1).
Figure 3-8	DAC test waveforms.
Figure 3-9	CV and CC DAC and amplifiers (from Figure 3-1).
Figure 3-10	Serial Down circuit (from Figure 3-1).
Figure 3-11	Secondary interface circuit (from Figure 3-1).
Figure 3-12	Slow downprogramming circuit (from Figure 3-1).

Troubleshooting Test Points

The troubleshooting charts reference test points listed in Table 6-3 of Chapter 6. Test points are identified by an encircled number (such as U in schematic diagrams and component location drawings, also in Chapter 6).

Bias and Reference Supplies

Many of the following troubleshooting procedures begin by checking the bias and/or reference voltages. Table 6-3 lists the test points for these voltages and gives the correct reading for each. The circuit board component location diagrams identify these points on each board.

34 Troubleshooting