Test equipment and power supplies · E364xA family

Agilent E3646A: troubleshooting and error codes

The ServiceForge knowledge base holds 8 documented symptoms for the Agilent E3646A, with 14 ranked causes, 29 diagnostic checks with test points and expected values, and 24 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Bias supplies output voltage out of specification caution

One or more bias supply voltages read outside tolerance range

Ranked causes

1. Input to voltage regulator more than 2V below minimum required dropout (occasional)
2. Heavy load on bias supplies pulling down regulator output (occasional)
3. Bias supply regulator failure (rare)

First check

Measure +5V floating bias supply voltage

Test point: U14 pin 2
Expected: +4.75 V to +5.25 V, +/-0.25 V
Tools: Digital multimeter

4 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit fails self-test

Self-test does not complete successfully or returns failures

Ranked causes

1. Incorrect power-line voltage setting selected (common)
2. Terminal connections present during self-test (common)
3. DAC U8 on PC board failure (occasional)

First check

Verify power-line voltage setting

Test point: Unit menu or front panel setting
Expected: Correct voltage setting for local power supply

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Local bias supplies inactive or out of specification caution

Local bias supplies in ADC or front panel section not producing correct output

Ranked causes

1. Main bias supply voltage below minimum required for local regulator (occasional)
2. Local bias regulator failure or load short (rare)

First check

Verify local bias supplies in ADC ac input section are active

Test point: ADC ac input local bias supply outputs
Expected: Correct bias voltage present

1 more check with pass and fail actions are in ServiceForge. Connect ServiceForge to your AI

Unit reports errors 740 to 750

Errors 740–750 displayed after power loss during calibration or state change

Ranked causes

1. Power loss during calibration or instrument state change (common)
2. Hardware failure (occasional)

First check

Recalibrate unit or reset non-volatile state

Test point: Unit display
Expected: Errors cleared; unit operates normally

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Exit and completion

Repeat all voltage, OVP, and current calibration steps for each output, then exit calibration mode when successful.

Ranked causes

1. Calibration sequence requires completion for all outputs (unknown)

First check

Verify all Output 1 calibrations completed

Test point: Display
Expected: All voltage, OVP, and current steps completed

3 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Output current

Adjust current calibration constants at low, mid, and high points using shunt resistor (0.1 Ω) and DVM measurement after voltage and OVP calibration.

Ranked causes

1. Current calibration constants require adjustment (unknown)

First check

Connect 0.1 Ω shunt resistor across output terminals

Test point: Output terminals
Expected: Shunt resistor connected in parallel with output

5 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Output voltage

Adjust voltage calibration constants at low, mid, and high points using front panel or remote interface after 1-hour warm-up with no load.

Ranked causes

1. Voltage calibration constants require adjustment (unknown)

First check

Ensure 1-hour warm-up period has elapsed

Test point: Power supply warm-up time
Expected: 1 hour minimum

5 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Over-voltage protection (OVP)

Adjust OVP calibration constant after voltage calibration is complete. Automatic procedure takes approximately 30 seconds.

Ranked causes

1. OVP calibration constant requires adjustment (unknown)

First check

Ensure voltage calibration completed successfully

Test point: Display
Expected: VOLTAGE CAL message displayed

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`701`	Cal security disabled by jumper	Calibration security feature is disabled	warning
`702`	Cal secured	Calibration operation completed with security enabled	info
`703`	Invalid secure code	Entered calibration security code does not match stored code	error
`704`	Secure code too long	Calibration security code exceeds maximum length	warning
`705`	Cal aborted	Calibration process was halted before completion	error
`706`	Cal value out of range	Measured or entered calibration value exceeds acceptable limits	error
`708`	Cal output disabled	Calibration output function is disabled	warning
`712`	Bad DAC cal data	Digital-to-analog converter calibration data is corrupted or invalid	error
`713`	Bad readback cal data	Readback calibration constants are corrupted	error
`714`	Bad OVP cal data	Over-voltage protection calibration data is invalid	critical
`717`	Cal OVP status enabled	Over-voltage protection remains enabled during calibration	warning
`718`	Gain out of range for gain error correction	Measured gain value outside acceptable correction range	error
`740`	Cal checksum failed, secure state	Checksum error in security state calibration data block	critical
`740–750`	Range of instrument state or calibration errors	Power loss during calibration or while changing instrument non-volatile state	error
`741`	Cal checksum failed, string data	Checksum error in string parameter calibration block	error
`743`	Cal checksum failed, store/recall data in location 1	Checksum error in memory location 1 calibration storage	error
`744`	Cal checksum failed, store/recall data in location 2	Checksum error in memory location 2 calibration storage	error
`745`	Cal checksum failed, store/recall data in location 3	Checksum error in memory location 3 calibration storage	error
`746`	Cal checksum failed, DAC cal constants	Checksum error in DAC calibration constant block	critical
`747`	Cal checksum failed, readback cal constants	Checksum error in readback calibration constant block	critical
`748`	Cal checksum failed, GPIB address	Checksum error in GPIB interface address storage	warning
`749`	Cal checksum failed, internal data	Checksum error in internal calibration data block	critical
`754`	Cal checksum failed, store/recall data in location 4	Checksum error in memory location 4 calibration storage	error
`755`	Cal checksum failed, store/recall data in location 5	Checksum error in memory location 5 calibration storage	error

Likely causes and actions for each code are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.