Test equipment and power supplies · 60xx series family

Agilent 6033A: troubleshooting and error codes

The ServiceForge knowledge base holds 26 documented symptoms for the Agilent 6033A, with 45 ranked causes, 85 diagnostic checks with test points and expected values, and 16 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Signature mismatch at data or address pin

Measured signature at IC pin differs from reference table value, indicating signal integrity issue or component fault

Ranked causes

1. IC pin shorted to Vcc or ground (common)
2. Two pins shorted together (occasional)
3. PCB trace or solder joint discontinuity (occasional)
4. Faulty component loading down node (occasional)

First check

Compare measured signature to Table 3-4 reference value

Test point: Target address or data line pin on processor IC
Expected: Exact match to Table 3-4 entry for firmware revision

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

Data and address lines not toggling

Address lines A0-A15 or data lines D0-D7 not toggling on secondary interface ICs U6, U8, U12, U14, U16, U17, U36

Ranked causes

1. Data or address line shorted high or low (common)
2. Socketed IC fault (occasional)
3. GPIB assembly fault (occasional)

First check

Check address lines A0 to A15 for toggling

Test point: U6, U8, U12, U14, U16, U17, U36
Expected: Toggling

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

Front panel RPG and switch input malfunction

Rotary pulse generator (RPG) or front panel switches not responding correctly to user input

Ranked causes

1. U11 shift register defective (occasional)
2. U12 flip-flop defective (occasional)
3. U18 gate IC defective (occasional)

First check

Measure signature at shift register U11 input

Test point: U11-1
Expected: 1ABC

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

No output from power supply high voltage

Unit produces no DC output voltage; FETs may fail from excessive power dissipation if off-pulses or power-limit comparator fails

Ranked causes

1. PWM-OFF and PWM-ON both low; control circuit failure (common)
2. PWM-ON high, PWM-OFF low or high; A4Q3 and A4Q4 PFETs failed (common)
3. Power-limit comparator failure; both PWM pulses absent (occasional)

First check

Measure bias voltages and PWM signals

Test point: A2 control board test fingers A2J3
Expected: PWM-OFF and PWM-ON present as 1.7µs TTL pulses at 20KHz

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

Clock signal frequencies incorrect

Clock signals at C7+, C8+ (12MHz from Y2), J5-8 (6MHz from U14), or U35-12 not at specified frequency

Ranked causes

1. Crystal oscillator Y2 fault (unknown)
2. Clock divider circuit fault (unknown)

First check

Measure frequency at C7+ and C8+ clock nodes

Test point: C7+, C8+
Expected: 12MHz
Tools: Frequency counter, oscilloscope

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

Current limit circuit not functioning caution

Unit does not limit output current to specified maximum; CC circuit defective

Ranked causes

1. CC (constant current) circuit defective on A2 board (common)
2. Maximum current below specification; CC clamp circuit failure (occasional)

First check

Set output to rated current limit; measure actual output current

Test point: Unit output terminals with load
Expected: 30Adc (6033A) or 10Adc (6038A) maximum
Tools: DMM or clamp ammeter

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Data or address line shorted high or low

Unit will not enter SA mode despite correct J5 jumper positioning

Ranked causes

1. Data line shorted high or low (occasional)
2. Address line shorted high or low (occasional)

First check

Attempt to place unit in primary SA mode with J5 jumper at pins 3 and 4

Test point: J5 jumper position and front panel display
Expected: Display shows 'SA SA' within normal startup time

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Front panel address latch or decoder malfunction

Address decoding not functioning correctly, affecting LED display multiplexing or front panel control

Ranked causes

1. U15 address latch defective (occasional)
2. Address decoder IC defective (U13, U14, or U16) (occasional)

First check

Measure signature at address latch U15 input pins during power cycle

Test point: U15-9, U17-3,6
Expected: Cycle power to unit - Lo to Hi after approx. 160 ms

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

Maximum voltage less than specified caution

Output voltage does not reach full rated voltage; CV circuit or input rectifier diodes defective

Ranked causes

1. CV circuit defective or low AC mains voltage (common)
2. Input rectifier diodes A1CR1–CR4 open or shorted (occasional)

First check

Measure output voltage at full setting

Test point: Unit output terminals
Expected: 20Vdc (6033A) or 60Vdc (6038A)

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

Readback DAC waveform incorrect high voltage

Readback DAC output waveform at U67-6 is not correct when varying output voltage from zero to full scale during selftest

Ranked causes

1. Readback DAC circuit fault (unknown)
2. Readback multiplexer fault (unknown)

First check

Toggle on/off switch repeatedly to perform selftest

Test point: On/off switch
Expected: Selftest routine executed

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

Troubleshooting -15V bias supply caution

Verification of -15V regulated output from voltage regulator A2U4

Ranked causes

1. Regulator A2U4 failure or feedback resistor A2R32 open (rare)
2. Zener diode A2VR2 shorted or interconnecting resistor open (occasional)

First check

Measure negative input voltage at A2U4 IN

Test point: A2U4 (IN), A2C16 (-)
Expected: ≈ - 24Vdc
Tools: DMM

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

Troubleshooting +15V bias supply caution

Verification of +15V output from voltage regulator A2U12 and zener feedback network

Ranked causes

1. Regulator A2U12 failure or adjustment resistor R29 open (rare)
2. Zener diode A2VR1 shorted or current-limiting resistor open (occasional)

First check

Measure input voltage at A2U12 IN

Test point: A2U12 (IN), A2C17 (+)
Expected: ≈ 24Vdc
Tools: DMM

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

Troubleshooting +5V bias supply caution

Verification of +5V regulated output from A2U6 PWM controller and A2U5 regulator

Ranked causes

1. PWM controller failure or compensation network open (rare)
2. Regulator A2U5 or output filter capacitor failed (occasional)

First check

Measure input voltage at A2J3-22

Test point: A2J3-22
Expected: ≈ 20Vdc
Tools: DMM

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

Troubleshooting Down Programmer circuit high voltage

Verification of down-programmer output loading function and 8.9V bias supply

Ranked causes

1. Comparator A4U3B threshold shifted or feedback divider open (rare)
2. Transistor A4Q6 shorted or output resistors open (occasional)

First check

Measure 8.9V bias output at A4U4 OUT

Test point: A4U4 (OUT)
Expected: 8.9Vdc, ±0.2V
Tools: DMM

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

+5V and PCLR circuit voltages incorrect high voltage

Voltages at PCLR and +5V circuit nodes U1-2, U1-3, U1-4, U1-6, or U1-8 not within specification

Ranked causes

1. +5V power supply fault (unknown)

First check

Measure voltage at U1-8

Test point: U1-8
Expected: ≈3.5Vdc, ±0.1V
Tools: DMM

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

Blank front panel Option 001 troubleshooting

Difficulty isolating defects in Option 001 units without front panel indicators; flowchart provided for problem isolation

Ranked causes

1. Defect in specific section of power supply (unknown)

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Current DAC output incorrect high voltage

CC DAC not producing expected current at output nodes U68-6 and U65-6 when front panel current control is varied from zero to full scale

Ranked causes

1. CC DAC circuit fault (unknown)

First check

Turn off unit and connect short across output terminals

Test point: Output
Expected: Short circuit connected

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

Excessive output noise (>1 kHz) caution

Output contains high-frequency noise above 1 kHz, indicating transformer, filter, or snubber issues

Ranked causes

1. Transformer T1 or output filter defective; snubber network failure (common)

First check

Measure output noise spectrum

Test point: Unit output terminals
Expected: Noise <1 kHz peak-to-peak
Tools: Oscilloscope

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

Front panel LED display segment or indicator malfunction

One or more 7-segment LED displays or individual LED indicators not illuminating or showing incorrect segments

Ranked causes

1. Faulty LED driver IC (U1 to U10) (common)

First check

Place unit in primary SA mode and measure signature at LED driver input pin 1

Test point: U1 to U10-1
Expected: 6H15

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

Front panel operation unavailable

Option 001 unit has no front-panel controls and indicators except LINE switch, OVP ADJUST control, and pilot light

Ranked causes

1. Unit shipped with Option 001 blank front panel (common)

First check

Verify available controls

Test point: Front panel
Expected: LINE switch, OVP ADJUST control, and ac input pilot light only

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

Incorrect signature analyzer reading in primary mode

Front panel display does not show 'SA SA' or LEDs do not all illuminate when unit placed in primary SA mode

Ranked causes

1. U14 defective (common)

First check

Verify unit placed in primary SA mode by moving J5 jumper

Test point: J5 jumper
Expected: Pins 3 and 4 connected (SA mode position)

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

Output current oscillation high voltage

Output current oscillates during power section operation

Ranked causes

1. Differentiator circuit fault (common)

First check

Observe output current oscillation

Test point: Output
Expected: No oscillations

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

Troubleshooting CC (Constant Current) circuit caution

Verification of current monitor amp, CC error amp and differentiator stabilization

Ranked causes

1. CC Error Amp A2U2B gain or offset fault (rare)

First check

Measure current monitor output IM at A2U1 with 0.5A load

Test point: IM
Expected: 0.50Vdc (1/6 of 0.5A = 0.083V per amp, but expect 0.50V), ±0.05V
Tools: DMM

4 more checks with pass and fail actions are in ServiceForge. Connect ServiceForge to your AI

Troubleshooting CV (Constant Voltage) circuit caution

Verification of voltage monitor amp, CV error amp and inner-loop stabilization

Ranked causes

1. CV Error Amp A2U8 offset shift or oscillation in inner loop (occasional)

First check

Measure voltage monitor output VM at A2U10C-8

Test point: A2U10C-8
Expected: 3.75Vdc, ±0.1V
Tools: DMM

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

Troubleshooting DC-to-DC Converter high voltage

Verification of PFET drivers, on/off pulse generators and power mesh switching on A4 board

Ranked causes

1. PFET gate drive signal weak or absent (occasional)

First check

Measure PWM-ON input waveform at A2J3-26

Test point: A2J3-26 (PWM-ON)
Expected: waveform #1
Tools: Oscilloscope

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

Voltage DAC output incorrect high voltage

CV DAC not producing expected voltage at output nodes U69-6 and U64-6 when front panel voltage control is varied from zero to full scale

Ranked causes

1. CV DAC circuit fault (unknown)

First check

Measure CV DAC output at U69-6 with voltage set to zero

Test point: U69-6
Expected: 0V
Tools: DMM

3 more checks 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
`ERROR 10`	Internal ROM Test failure		error
`ERROR 12`	ADC Zero Too High		error
`ERROR 13`	Voltage DAC Full Scale Low		error
`ERROR 14`	Voltage DAC Full Scale High		error
`ERROR 15`	Voltage DAC Zero Low		error
`ERROR 16`	Voltage DAC Zero High		error
`ERROR 17`	Current DAC Full Scale Low		error
`ERROR 18`	Current DAC Full Scale High		error
`ERROR 19`	Current DAC Zero Low		error
`ERROR 20`	Current DAC Zero High		error
`ERROR 4`	External RAM Test failure		error
`ERROR 5`	Internal RAM Test failure		error
`ERROR 6`	External ROM Test failure		error
`ERROR 7`	GPIB Test failure		error
`ERROR 8`	GPIB address set to 31		warning
`STARTUP_FAILURE`	Power supply fails turn-on self-test	Power supply does not pass self-test or indicates malfunction on startup	critical

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.