Chapter 5
5-13
Power Supply Troubleshooting
If the Green LEDs of the A8 Are Not All ON
If the Green LEDs of the A8 Are Not All ON
The green LEDs along the top edge of the A8 post regulator are normally on.
Flashing LEDs on A8 indicate that the shutdown circuitry on the A8 post regulator is
protecting power supplies from overcurrent conditions by repeatedly shutting them down.
This may be caused by supply loading on A8 or on any other assembly in the analyzer.
Remove A8, Maintain A15W1 Cable Connection
1. Switch off the analyzer.
2. Remove A8 from its motherboard connector, but keep the A15W1 cable connected to A8.
3. Remove the display power cable.
) to chassis ground with a clip lead.
5. Switch on the analyzer and observe the green LEDs on A8.
• If any green LEDs other than +5 VD are still off or flashing, continue to
A8 Fuses and Voltages” on page 5-13
.
• If all LEDs are now on steadily except for the +5 VD LED, the A15 preregulator and
A8 post regulator are working properly and the trouble is excessive loading
somewhere after the motherboard connections at A8. Continue to
Check the A8 Fuses and Voltages
Check the fuses along the top edge of A8. If any A8 fuse has burned out, replace it. If it
burns out again when power is applied to the analyzer, A8 or A15 is faulty. Determine
which assembly has failed as follows.
1. Remove the A15W1 cable at A8. (See
2. Measure the voltages at A15W1P1 (see
) with a voltmeter
having a small probe.
3. Compare the measured voltages with those in
• If the voltages are within tolerance, replace A8.
• If the voltages are not within tolerance, replace A15.
If the green LEDs are now on, the A15 preregulator and A8 post regulator are working
properly and the trouble is excessive loading somewhere after the motherboard
connections at A8. Continue to
next.
Remove the Assemblies
1. Switch off the analyzer.
2. Install A8. Remove the jumper from A8TP2 (AGND) to chassis ground.
Summary of Contents for 8753ES
Page 14: ...Contents xiv Contents ...
Page 15: ...1 1 1 Service Equipment and Analyzer Options ...
Page 26: ...1 12 Chapter1 Service Equipment and Analyzer Options Service and Support Options ...
Page 27: ...2 1 2 System Verification and Performance Tests ...
Page 203: ...3 1 3 Adjustments and Correction Constants ...
Page 262: ...3 60 Chapter3 Adjustments and Correction Constants Sequences for Mechanical Adjustments ...
Page 263: ...4 1 4 Start Troubleshooting Here ...
Page 297: ...5 1 5 Power Supply Troubleshooting ...
Page 317: ......
Page 318: ...6 1 6 Digital Control Troubleshooting ...
Page 337: ...6 20 Chapter6 Digital Control Troubleshooting GPIB Failures ...
Page 338: ...7 1 7 Source Troubleshooting ...
Page 369: ...7 32 Chapter7 Source Troubleshooting Source Group Troubleshooting Appendix ...
Page 370: ...8 1 8 Receiver Troubleshooting ...
Page 381: ...8 12 Chapter8 Receiver Troubleshooting Troubleshooting When One or More Inputs Look Good ...
Page 382: ...9 1 9 Accessories Troubleshooting ...
Page 389: ...9 8 Chapter9 Accessories Troubleshooting Inspect the Error Terms ...
Page 390: ...10 1 10 Service Key Menus and Error Messages ...
Page 439: ...10 50 Chapter10 Service Key Menus and Error Messages Error Messages ...
Page 440: ...11 1 11 Error Terms ...
Page 451: ...11 12 Chapter11 Error Terms Error Correction ...
Page 452: ...12 1 12 Theory of Operation ...
Page 482: ...13 1 13 Replaceable Parts ...
Page 487: ...13 6 Chapter13 Replaceable Parts Ordering Information Figure 13 1 Module Exchange Procedure ...
Page 500: ...Chapter 13 13 19 Replaceable Parts Replaceable Part Listings Figure 13 7 8753ET Cables Top ...
Page 502: ...Chapter 13 13 21 Replaceable Parts Replaceable Part Listings Figure 13 8 8753ES Cables Top ...
Page 512: ...Chapter 13 13 31 Replaceable Parts Replaceable Part Listings Figure 13 13 8753ES Cables Front ...
Page 544: ...14 1 14 Assembly Replacement and Post Repair Procedures ...
Page 550: ...Chapter 14 14 7 Assembly Replacement and Post Repair Procedures Covers Figure 14 2 Covers ...
Page 597: ...14 54 Chapter14 Assembly Replacement and Post Repair Procedures Post Repair Procedures ...