Agilent Technologies 6680A Test Equipment Required, Troubleshooting Procedures Power-On Selftest

Test Equipment Required

Table 3-1. Test Equipment Required

Equipment	Purpose	Recommended Model
Logic Probe	To check states of data lines.	Agilent 545A
Test Clips	To gain access to IC pins.	AP Products No. LTC
Ammeter/Current Shunt	To measure output current.	Agilent 6680A & 6681A:
		Burster 1280
		Agilent 6682A, 6683A & 6684A:
		Guildline 9230/300
Oscilloscope	To check waveforms and signal levels.	Agilent 54504A
Signature Analyzer	To troubleshoot most of the primary	Agilent 5005A/B
	and secondary interface circuits.
GPIB Controller	To communicate with power supply via	Agilent BASIC series
	the GPIB (for system units).
DC Voltmeter	To measure output voltage and current,	Agilent 3458A
	bias and references.

Troubleshooting Procedures

Power-On Selftest

Description

The procedures in the troubleshooting charts make use of the power-on selftest. The power-on selftest tests the front panel, GPIB interface (for GPIB system power supplies), and secondary interface circuits. If the power supply fails the selftest, the output remains disabled (turned off) and the front panel normally displays an error code or message (see Table 3-2). The message is displayed indefinitely and the power supply will not accept GPIB or front panel commands.

Disabling The Power-On Selftest

In order to perform troubleshooting procedures that require programming of the power supply, you must disable the power-on self test. Do this as follows:

1.Turn off the power supply.

2.Hold down the key and turn on the supply.

3.Continue holding down the for 2 seconds and wait until the PWR ON INIT indicator goes off.

4.The power supply is now on without executing power-on selftest.

Using the *TST? Query (GPIB Systems Supplies Only)

You can get the power supply to execute a partial selftest by sending it the GPIB *TST? query command. Table 3-2 shows the tests that are performed in response to this command. These tests do not interfere with normal operation or cause the output to change. The command returns a value of "0" if all tests pass. Otherwise, the command returns the error code of the first test that failed. No error codes are displayed on the front panel and the power supply will attempt to continue normal operation.

32 Troubleshooting