HP 4395A - Page 17

7. Power Supply Troubleshooting
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
START HERE ................................ 7-3
1. Check the Fan is Rotating .. .... .... .... .... .... .. 7-3
2. Check the A50 SHUTDOWN LED . . . . . . . . . . . . . . . . . . . . . 7-3
A50 Shutdown LED ........................... 7-3
3. Check the A1 +5 VD LED . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Measure the A1 +5 VD Voltage . . . . . . . . . . . . . . . . . . . . . . 7-4
FIND OUT WHY THE FAN IS NOT ROTATING .... .... .... .... . 7-5
1. Check the Line Voltage, Selector Switch Setting, and Fuse . . . . . . . . . 7-5
2. Check the A50 SHUTDOWN LED . . . . . . . . . . . . . . . . . . . . . 7-5
FIND OUT WHY THE A50 SHUTDOWN LED IS OFF .. .... .... .... 7-6
1. Disconnect the Cable from the A1J10 .................. 7-6
2. Remove Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
3. Disconnect the Cable from the A9J2 . . . . . . . . . . . . . . . . . . . 7-6
FIND OUT WHY THE A1 +5 VD LED IS NOT ON STEADILY .......... 7-8
1. Check the A40 Pre-Regulator .. .... .... .... .... .... 7-8
2. Check the A50 DC-DC Converter . . . . . . . . . . . . . . . . . . . . . 7-8
3. Disconnect Cables on the A1 CPU .................... 7-9
4. Remove Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
5. Remove Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . .
7-10
TROUBLESHOOT THE FAN AND THE A50 DC-DC CONVERTER ........ 7-11
1. Troubleshoot the Fan .... .... .... .... ... .... ...
7-11
2. Troubleshoot the A50 DC-DC Converter .. .... .... .... ...
7-12
8. Digital Control Troubleshooting
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-1
A1 CPU Replacement .. .... .... .... .... .... .... ..
8-3
FIRMWARE INSTALLATION .........................
8-4
Ordering the Firmware Diskette ......................
8-4
Installing the Firmware .... .... .... .... .... ... ...
8-4
START HERE ................................
8-6
1. Check the Power-On Sequence . . . . . . . . . . . . . . . . . . . . . .
8-6
Check the 4
Ch 1
5 and 4
Ch 2
5 Operations . . . . . . . . . . . . . . . . . . .
8-6
Check the A1 Eight LEDs ........................
8-6
2. Check Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
3. Check the A1 DRAM and Flash Memory ................. 8-7
4. Check the A1 Volatile Memory . . . . . . . . . . . . . . . . . . . . . . 8-8
5. Check the A30 Front Keyboard ..................... 8-9
6. Check the A53 FDD . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
7. Check the A32 I-BASIC Interface and the mini DIN Keyboard .. .... . 8-9
8. Check the A33 EXT I/O Interface ....................
8-9
TROUBLESHOOT THE A51 GSP and A52 LCD . . . . . . . . . . . . . . . . .
8-11
1. Run the Internal Test 3: A51 GSP. ....................
8-11
2. Check the A52 LCD(Liquid Crystal Display) . . . . . . . . . . . . . . . .
8-11
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