Table 3-1 gives the signals for each of the test points on the control board test connector. This connector is provided in service kit P/N 06033-60005. The measurements given here include bias and reference voltages as well as power supply status signals and waveform information.
Table 3-2 provides troubleshooting information based on the status of the PWM-ON and PWM-OFF signals which drive the PFETs. This table is used for no-output failures.
Tables 3-3 and 3-4 give measurements for the test points on the A3 front-panel board and possible failure symptoms respectively.
Table 3-5 describes possible symptoms for overall performance failures of the power supply. It is necessary to have a properly working front-panel before using this table.
Chapter 6 contains schematic diagrams and voltage levels, and component location diagrams to help you locate components and test points.
Make most voltage measurements (except DC-to-DC Converter and ac mains-connected circuits) referenced to the unit's output common which is accessible at rear-panel terminal VM. All voltages are ± 5% unless a range is given.
Using the Tables
Typically there will be two types of power supply failures; no-output and performance failures.
1.No-OUTPUT FAILURE: Start with the TROUBLESHOOTING NO-OUTPUT FAILURES section which references Tables 3-1 and 3-3.
2.PERFORMANCE FAILURE: If the power supply produces an output but does not perform to specifications, begin by verifying the measurements at the A2J7 test connector using Table 3-1. Next, verify the front-panel by doing the procedure outlined in the FRONT-PANEL TROUBLESHOOTING section. After the front-panel has been verified consult Table 3-5 for the performance failure symptom which seems closest to the one observed and proceed to the functional circuit given for that failure.
The circuits referenced in Tables 3-2 and 3-5 are derived from functional blocks of circuits in the power supply. These blocks are given in the Power Supply Blocks section starting on page 35. Troubleshooting information for each block will include a brief description of the circuit involved. The columns provided in each block are as follows:
NODE: | This column lists the nodes where the measurements should be taken. In some cases this will be |
| stated as NODE ( + ) and NODE (- ) where the first is the test node and the second is the |
| reference. |
SETUP: | If a certain setup is required for the measurement, it will be given in this column. |
MEASUREMENT: | This column indicates what the expected measurement is for the given node. |
SOURCE: | If applicable, the components which generate the signal will be provided in this column . |
Some blocks will have Input and Output sections. The input section will have a source column to indicate which components generated the measured signal. The output section will list all the important output signals from that block. However, because the outputs of one block are the inputs to another, the schematic should be consulted if an output measurement is incorrect. This will indicate the next circuit block to be trouble shot.