Agilent Technologies 46A C Replace any shorted assembly, D Override the Remote Inhibit signal

Chapter 5: Troubleshooting

Power Supply Trouble Isolation

CReplace any shorted assembly.

You can locate the shorted assembly by disconnecting assemblies from the power supply, one at a time. Use the power supply distribution chart in table 5-4 as a guide to locating the shorted assembly.

Reconnect Assemblies and Cables

Reconnect all assemblies after testing. The oscilloscope must have all cables connected for correct power up.

If you want to test the power supply without any assemblies connected, the +5 V supply must be loaded to 2 A. Use two 5Ω, 10W resistors between the +5 V output and ground.

Table 5-4	Power Supply Distribution
	Assembly	+5.1 V	-5.2 V	Ground	+12.2 V	-12.2 V	3.3 V (generated on Motherboard)
	Acquisition	X	X	X	X	X
	Motherboard	X	X	X	X	X	X
	Probe Power &	X		X	X	X
	Control
	Front-Panel	X		X
	Keyboard
	Scope Interface	X		X			X
	Board
	Display Board	X		X	X	X	X
	Backlight			X	X
	Inverter
	Flat Panel	X		X			X
	Display
	Floppy Disk Drive	X		X
	Hard Disk Drive	X		X

DOverride the Remote Inhibit signal.

Power up the unit by connecting a resistor between pin 3 and pin 11 of power supply control cable W2. Use a resistor in the range of 196-220Ω, 1/8 W, such as Agilent Technologies

P/N 0698-3440 or 0757-0407. See figure 5-4.

Figure 5-4

Power-up Sense Resistor Connection

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