Test Equipment Required; Troubleshooting Procedures; Power-On Selftest; Description - Agilent Technologies 6571A Service Manual

Test Equipment Required

Equipment
Logic Probe
Test Clips
Ammeter/Current Shunt
Oscilloscope
Signature Analyzer
GPIB Controller
DC Voltmeter

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) or Isolator Board (bench 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 selftest. 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
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.
30 Troubleshooting
Table 3-1. Test Equipment Required
Purpose
To check states of data lines.
To gain access to IC pins.
To measure output current.
To check waveforms and signal levels.
To troubleshoot most of the primary
and secondary interface circuits.
To communicate with power supply via
the GPIB (for system units).
To measure output voltage and current,
bias and references.
for 2 seconds and wait until the PWR ON INIT indicator goes off.
Recommended Model
Agilent 545A
AP Products No. LTC
Agilent 6571A & 6671A:
Guildline 9230/300
Agilent 6572A-75A & 6672A-75A:
Guildline 9230/100
Agilent 54504A
Agilent 5005A/B
Agilent BASIC Series
Agilent 3458A