Fluke 5725A Stereo Amplifier User Manual


 
5725A
Instruction Manual
4-10
Inside the 5725A, B-SENSE LO is buffered by the 5725A, with the equivalent
voltage called MCOM.
B-FEEDBACK
During ac voltage operation, B-FEEDBACK is the output of the High Voltage Sense
assembly; this signal represents B-SENSE HI divided by -100, and drives the 5700A
ac/dc thermal sensor. During low-frequency ac voltage calibration, this is the sense
path for the -260V dc from the 5700A Power Amplifier.
During ac current operation, B-FEEDBACK is the output of the current calibration
amplifier. It represents the output current divided by -5 and drives the 5700A
Oscillator feedback.
During dc current operation, voltage from the 5700A 2V dc range is fed to the
5725A on B-FEEDBACK.
If B-FEEDBACK is out of tolerance during 5725A ac voltage or current operation
but no other faults are reported, the 5700A sends a message to the 5725A asking for
a sequenced shutdown into standby, and displays a fault message on its Control
Display. The 5725A FAULT indicator lights. A faulty 5700A/5725A interface
connection could cause this problem.
4-13. Functional Summaries by Assembly
For an overview of all the assemblies in the 5725A and the functions contained on each,
refer to Figure 4-1, the overall block diagram, and the following list:
Interconnect Assembly (A1):
Connectors and traces to link other assemblies and fan
High voltage transformer secondary switching circuitry
Power Supply Assembly (A4):
Rectifiers for high voltage supplies
Filters for high voltage supplies
High voltage current-limit circuitry
High voltage supply-monitoring circuitry
Rectifiers for system supplies
Filters for system supplies
Regulators for system supplies
Rectifiers for fan supply
Filter for fan supply
Digital Assembly (A5)
LED front panel status annunciators
CPU, RAM, ROM, EEROM, watchdog timer, logic
Current Amplifier Assembly (A2):
Transconductance amplifier
Current shunt
Heat sink and current power devices
5700A current routing circuits
Filters for high current supply
Rectifier bridge for high current supply
Regulators for low current supply
Current heat sink temperature monitor