Test equipment and power supplies · E363xA family

Agilent E3630A: troubleshooting and error codes

The ServiceForge knowledge base holds 27 documented symptoms for the Agilent E3630A, with 46 ranked causes, 54 diagnostic checks with test points and expected values, and 0 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

High output voltage on -20V supply

Output voltage on -20V supply more than 1% greater than +20V supply in fixed tracking mode

Ranked causes

1. Shorted Q8 transistor (occasional)
2. Open CR20 or R14, or defective U8A (occasional)
3. Defective Q7 transistor (occasional)

First check

Attempt to turn off Q8 by shorting emitter-to-base

Test point: Q8 emitter and base
Expected: Output voltage becomes near zero when shorted

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

High output voltage on +20V supply

Output voltage measures higher than rated specification

Ranked causes

1. Shorted Q9 transistor (occasional)
2. Open CR13 or R36, or defective U6A (occasional)
3. Defective Q5 transistor (occasional)

First check

Attempt to turn off Q9 by shorting emitter-to-base

Test point: Q9 emitter and base
Expected: Output voltage becomes near zero when shorted

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

High ripple on output

Excessive ripple voltage measured on power supply output

Ranked causes

1. Ground loops in operating setup (common)
2. Open main rectifiers CR1, CR25, or CR26 (common)
3. Supply operating in current limit mode (occasional)

First check

Inspect for ground loops in test setup

Test point: Operating setup
Expected: No ground loops present

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

Low output voltage on -20V supply

Output voltage on -20V supply more than 1% lower than +20V supply in fixed tracking mode

Ranked causes

1. Open Q8, Q3, or R24 (occasional)
2. Defective U8B (occasional)
3. Defective U8A, shorted CR21 or CR22, open R15, shorted R41, or leaky/shorted C6 (occasional)

First check

Measure voltage at base of Q7

Test point: Q7 base
Expected: Measured voltage more than 0 volt

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

Low output voltage on +20V supply

Output voltage measures lower than rated specification

Ranked causes

1. Open Q9, Q6, R26, or CR5 (occasional)
2. Defective U6B (occasional)
3. Defective U6A, shorted CR14 or CR15, open R39, shorted R36, or leaky/shorted C7 (occasional)

First check

Measure voltage at base of Q5

Test point: Q5 base
Expected: Measured voltage less than 0 volt

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

Low output voltage on +6V supply

Output voltage on +6V supply measures lower than rated specification

Ranked causes

1. Open Q1, Q6, R25, or CR5 (occasional)
2. Defective U2B (occasional)
3. Defective U2A, shorted CR9 or CR10, open R29, shorted R11, or leaky/shorted C5 (occasional)

First check

Measure voltage at base of Q4

Test point: Q4 base
Expected: Measured voltage less than -0.6V

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

Oscillation or poor transient response time

Supply exhibits oscillations at various frequencies or slow response to load changes

Ranked causes

1. Open capacitor C11, C20, or C25 causing high frequency oscillation above 50 kHz (occasional)
2. Defective output capacitor C2, C3, or C4 (occasional)
3. Open capacitor C12, C19, or C24 in current limiting mode (occasional)

First check

Measure oscillation frequency

Test point: Output
Expected: No oscillations or within specification

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

Excessive heat caution

Power supply generates abnormal heat

Ranked causes

1. Defective preregulator control circuit (common)
2. Shorted rectifier CR27, CR28, CR31, or CR32 (common)

First check

Allow supply to warm up and measure component temperatures

Test point: Preregulator area, rectifier area
Expected: Temperatures within normal operating range

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

High output voltage on +6V supply

Output voltage on +6V supply measures higher than rated specification

Ranked causes

1. Shorted Q1 transistor (occasional)
2. Defective Q4, open CR6 or R11, or defective U2A (occasional)

First check

Attempt to turn off Q1 by shorting emitter-to-base

Test point: Q1 emitter and base
Expected: Output voltage becomes near zero when shorted

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

Poor load and line regulation

Output voltage does not remain stable with changes in load or input line voltage

Ranked causes

1. Incorrect bias and reference voltages (common)
2. Open main rectifiers or filter capacitors (common)

First check

Measure bias and reference voltages

Test point: Bias and reference circuits
Expected: Within specification per Table A-4

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

Transient voltage overshoot at turn-on or turn-off

Output voltage exceeds specification at power supply startup or shutdown

Ranked causes

1. Shorted Q3 causing overshoot only in -20V supply (occasional)
2. Open Q2 or shorted Q6 causing overshoot in all three outputs (occasional)

First check

Measure transient overshoot voltage at turn-on/turn-off

Test point: Output
Expected: Overshoot within specification

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

Will not current limit

Supply does not reduce output current when load resistance decreases

Ranked causes

1. Open OR-gate diodes CR7, CR11, or CR18 (common)
2. Defective current limit amplifier U2, U6, U8, or U14 (common)

First check

Test OR-gate diodes for opens

Test point: CR7, CR11, CR18
Expected: All diodes conduct in forward direction

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

Output voltage clamped above 10V for ±20V output

Output voltage cannot be set below approximately 10V on ±20V supplies

Ranked causes

1. Defective preregulator control circuit (common)

First check

Attempt to set output voltage below 10V

Test point: Output terminals
Expected: Output voltage adjustable to zero volts

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

Verify ±20V output tracking

Check that +20V and -20V outputs track each other within tolerance

Ranked causes

1. Tracking ratio circuit misaligned (occasional)

First check

Set +20V output and measure -20V output

Test point: -20V terminal to COM
Expected: within 1% of +20V output (19.8V to 20.2V), ±1%
Tools: Digital voltmeter

Verify ammeter accuracy at +6V

Check front panel ammeter reading matches DVM calculation at 2.5A load

Ranked causes

1. Front panel ammeter out of calibration (common)

First check

Set up +6V output with 2.4Ω total load resistance (RL + sampling resistor)

Test point: +6V output
Expected: 2.5 amps A
Tools: Current sampling resistor, DVM

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

Verify ammeter accuracy at ±20V

Check front panel ammeter reading matches DVM calculation at 0.5A load on each 20V output

Ranked causes

1. Front panel ammeter out of calibration (common)

First check

Set up ±20V output with 40Ω total load resistance (RL + sampling resistor)

Test point: ±20V output
Expected: 0.5 A
Tools: Current sampling resistor, DVM

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

Verify common mode current

Measure AC current between COM terminal and chassis ground; should be less than 1 µA

Ranked causes

1. Output coupling capacitor leakage or ground plane fault (rare)

First check

Connect 100 kΩ resistor and 2200 pF capacitor in parallel between COM and chassis ground

Test point: 100 kΩ sampling resistor
Expected: voltage corresponding to less than 1 µA current
Tools: 100 kΩ resistor, 2200 pF capacitor, DVM

Verify current limit at +6V

Check that +6V output current limit increases gradually with load and limits at short circuit

Ranked causes

1. Current limit circuit fault or misadjustment (occasional)

First check

Apply variable load to +6V output and reduce RL gradually

Test point: +6V output current via sampling resistor
Expected: maximum 2.75A±5% (2.6125A to 2.8875A) before decreasing, ±5%
Tools: Variable resistor RL, current sampling resistor, DVM

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

Verify current limit at ±20V high voltage

Check short-circuit current limit of ±20V outputs is set correctly

Ranked causes

1. Current limit circuit fault or misadjustment (occasional)

First check

Connect test setup with short circuit in place of RL on +20V output

Test point: Current sampling resistor across short
Expected: 0.55A±5% (0.5225A to 0.5775A), ±5%
Tools: Current sampling resistor, DVM

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

Verify line regulation high voltage

Check output voltage stability when AC input varies ±10% from nominal

Ranked causes

1. Line regulation circuit misalignment or fault (rare)

First check

Apply -10% nominal AC input voltage with autotransformer and record DVM voltage

Test point: Output voltage at low line
Expected: maximum rated voltage
Tools: Variable autotransformer, electronic load, DVM

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

Verify load regulation

Check output voltage stability when load changes from full rated current to open circuit

Ranked causes

1. Load regulation circuit misalignment or fault (rare)

First check

Set electronic load to full rated current and record DVM voltage

Test point: Output voltage at full load
Expected: maximum rated voltage
Tools: Electronic load, DVM

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

Verify load transient response time

Measure time for output voltage to settle after load step change between half and full load

Ranked causes

1. Feedback network or compensation circuit misalignment (rare)

First check

Set electronic load to transient mode between 50% and 100% of full rated current at 1 kHz, 50% duty cycle

Test point: +20V output with oscilloscope
Expected: pulse width (t2-t1) at 15 mV from baseline ≤50 µsec
Tools: Electronic load, oscilloscope with AC coupling and sync

Verify output voltage accuracy

Front panel voltmeter reading may not match DVM reading; check ±20V and ±6V outputs

Ranked causes

1. Front panel voltmeter out of calibration (common)

First check

Measure +20V output voltage with DVM

Test point: +20V terminal to COM
Expected: 17 volts V
Tools: Digital voltmeter (DVM)

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

Verify rated output voltage

Check that +20V, -20V, and +6V outputs deliver rated voltage under full load

Ranked causes

1. Output voltage regulator circuit failure (occasional)

First check

Connect 40Ω 20W load resistors across both 20V outputs

Test point: +20V and -20V outputs
Expected: ±20V
Tools: Load resistors

Verify ripple and noise peak-to-peak voltage

Measure peak-to-peak noise with oscilloscope; should be less than 1.5 mV

Ranked causes

1. Output filter or bypass capacitor degradation (occasional)

First check

Connect oscilloscope across +20V output at full rated voltage in AC mode

Test point: +20V output
Expected: peak-to-peak less than 1.5 mV
Tools: Oscilloscope set to AC mode, 20 MHz bandwidth

Verify ripple and noise RMS voltage

Measure RMS noise voltage across each output; should be less than 0.35 mV

Ranked causes

1. Output filter or bypass capacitor degradation (occasional)

First check

Connect true RMS voltmeter across +20V output at full rated voltage

Test point: +20V output
Expected: less than 0.35 mV RMS
Tools: True RMS voltmeter

Verify variable tracking ratio

Check that TRACKING RATIO control can adjust -20V output across full range

Ranked causes

1. Variable tracking ratio circuit fault (rare)

First check

Adjust TRACKING RATIO control to VARIABLE and monitor -20V output

Test point: -20V output with DVM
Expected: adjustable from <0.5V to 19-21V
Tools: Digital voltmeter

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.