Fluke 5720A Power Supply User Manual


 
Troubleshooting
Interpreting Diagnostic Fault Codes
5
5-19
3315 A9/A10: 10 Ohm Cal Diag Fault
The 2/5/10V SOURCE circuit is set for 2V and connected across the 100 string on the
Ohms Main assembly. The resulting 0.2 V across the 10 portion is connected to the -
input of the Differential Amplifier on the Ohms Cal assembly. The output of the DAC
assembly is set to 2V and connected across the 100 k resistance in Z5 on the Ohms Cal
assembly. The resulting 0.2V across the 10 k portion of Z5 is connected to the +input
of the Differential Amplifier. The output of the Differential Amplifier is routed to the
adc circuit on the DAC assembly, via the RCL line, and measured for 0V ±3% ±15 mV.
Verify that the divided DAC voltage of 0.2V ±5% is at the +input of the Diff Amp by
connecting DMM hi to TP20 and low to TP10 of the Ohms Cal assembly. If this
measured voltage is out of tolerance, the Ohms Cal assembly (A9) is probably at fault.
3316 A9/A10: 19 Ohm Cal Diag Fault
The 2/5/10V SOURCE circuit is set for 2V and connected across the 190 string on the
Ohms Main assembly. The resulting 0.2V across the 10 portion is connected to the -
input of the Differential Amplifier on the Ohms Cal assembly. The output of the DAC
assembly is set to 2V and connected across the 100 k resistance in Z5 on the Ohms Cal
assembly. The resulting 0.2V across the 10 k portion of Z5 is connected to the +input
of the Differential Amplifier. The output of the Differential Amplifier is routed to the
adc circuit on the DAC assembly, via the RCL line, and measured for 0V ±3% ±15 mV.
A failure indicates the calibration of the 19 resistance on the Ohms Main assembly
(A10) is probably at fault.
3317 A9/A10: 100 Kilohm Ratio Fault
The 2/5/10V SOURCE circuit on the Ohms Cal assembly is set to 10V which is routed to
the Ohms Main assembly and connected to the 100 k string. The resulting 1V across
the 10 k portion is measured for 1V ±3% ±15 mV. A failure indicated the Ohms Main
assembly (A10) is probably at fault.
3318 A9/A10: 190 Kilohm Ratio Fault
The 2/5/10V SOURCE circuit on the Ohms Cal assembly is set to 10V which is routed to
the Ohms Main assembly and connected to the 190 k string. The resulting 1V across
the 19 k portion is measured for 1V ±3% ±15 mV. A failure indicated the Ohms Main
assembly (A10) is probably at fault.
3319 A9/A10: 1M Ohm Ratio Fault
The 2/5/10V SOURCE circuit on the Ohms Cal assembly is set to 10V which is routed to
the Ohms Main assembly and connected to the 1 M string. The resulting 1V across the
100 k portion is measured for 1V ±3% ±15 mV. Measure the 1 volt across the 100 k
string by connecting a DMM hi to TP14 and low to TP2 of the Ohms Cal assembly (A9).
If the voltage is out of tolerance, the Ohms Main assembly (A10) is probably at fault. If
the voltage is within tolerance, the Ohms Cal assembly (A9) if probably at fault.
3320 A9/A10: 1.9M Ohm Ratio Fault
The 2/5/10V SOURCE circuit on the Ohms Cal assembly is set to 10V which is routed to
the Ohms Main assembly and connected to the 1.9 M string. The resulting 1V across
the 190 k portion is measured for 1V ±3% ±15 mV. A failure indicated the Ohms Main
assembly (A10) is probably at fault.