SPECT cameras

ADAC Vertex Plus: troubleshooting and error codes

The ServiceForge knowledge base holds 60 documented symptoms for the ADAC Vertex Plus, with 70 ranked causes, 96 diagnostic checks with test points and expected values, and 101 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Encoder position discrepancy detected

System detects mechanical slip or linkage problems indicated by difference between encoder and potentiometer position readings.

Ranked causes

1. Drive chain fallen off sprocket (occasional)
2. Gear slipping relative to potentiometer (occasional)
3. Potentiometer slipping relative to encoder (occasional)
4. Encoder slipping relative to mechanism (occasional)
5. Mechanism slipping relative to potentiometer (occasional)

First check

Monitor encoder and potentiometer position agreement during motion

Test point: Display Panel error code status
Expected: No U3 error code

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

Calibration: Detector radius patient safety

Detectors may collide or hit table if radius calibration is incorrect, especially when selecting Cardiac 90 & Lock preprogram option or performing ECT studies with heads in 90° position.

Ranked causes

1. Radius calibration out of specification (common)
2. Radius Sensor locations not stored accurately (common)

First check

Position detector #1 at first calibration point

Test point: Brass Leadscrew Support Nut on right side of detector
Expected: 2.9 cm (11/8 inch) above black Thrust Support Block
Tools: Handcontrol, level

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

Calibration: Gantry rotation

Encoder and potentiometer positions must be synchronized for rotation mechanism. Calibration establishes the relationship between potentiometer voltage and encoder pulses.

Ranked causes

1. Potentiometer wiper not centered on new installation (common)
2. Calibration performed at incorrect angle range (occasional)

First check

Verify potentiometer wiper centering after installation

Test point: Potentiometer mid-range
Expected: 2000

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

Calibration: Motor Controller Gain and Speed

Gantry motions (Rotate, Translate, Radius, Table Z/X) require bidirectional speed balancing and max speed adjustment via potentiometers on Motor Controller boards to prevent stalling, Maytagging (overshooting), jerky movement, hunting, or motion errors.

Ranked causes

1. IR Comp pot out of adjustment (common)
2. Max Speed pot out of adjustment (common)

First check

Enter Cal Mode and access MC Gain option

Test point: Display Panel
Expected: MC Gain option appears with motion selection (G ROT, RAD 1, RAD 2, etc.)

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

Calibration: Motor Controller Initial Potentiometer Setup

Initial pot and switch positions on Motor Controller boards must be set to predetermined limits before adjustment of Max Speed and IR Comp pots. Five pots (DB, RevTQ, FwdTQ, SloSpd, AccDec) and SW 501 switches require one-time setup.

Ranked causes

1. Pots and switches not set to initial positions (common)
2. SW 501 switches not set to initial positions (occasional)

First check

Verify if installing new Motor Controller board

Test point: Hardware installation status
Expected: New controller board mounted on Motor Controller Panel Assembly

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

Calibration: Motor controller speed and stability caution

Motor controller boards on the Motor Controller Panel Assembly require calibration of Max Speed and IR Comp potentiometers to ensure proper gantry motion control without stalling or oscillation.

Ranked causes

1. Incorrect IR Comp setting causing directional speed mismatch (common)
2. Incorrect Max Speed setting causing stalling or oscillation (common)

First check

Verify motor speeds in opposite directions are equal

Test point: Motor motion in CW and CCW directions
Expected: Same speed in both directions

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

Potentiometer replacement procedure

Steps to replace a potentiometer on any gantry motion mechanism while ensuring correct centering and calibration.

Ranked causes

1. Potentiometer failure or drift (occasional)
2. Incorrect wiper position during installation (common)

First check

Center potentiometer wiper before installation

Test point: Potentiometer wiper position
Expected: Fully to one end, then 5 turns in opposite direction

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

Calibrate gantry motions

Perform voltage, speed, motor control gain and software limit tests for gantry translate, rotate, and other motions

Ranked causes

1. Routine calibration required (common)

First check

Navigate to Calibrate Motions menu

Test point: Gantry Display Panel
Expected: Calibrate Motions option displayed

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

Calibration: Detector 1 radius

Encoder and potentiometer synchronization for detector 1 radial motion (zoom in/out). Applies to all models except Cardio.

Ranked causes

1. Potentiometer wiper not centered on new installation (common)

First check

Verify potentiometer wiper centering after installation

Test point: Potentiometer mid-range
Expected: 2000

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

Calibration: Detector 2 radius

Encoder and potentiometer synchronization for detector 2 radial motion (zoom in/out). Applies to all models except Cardio.

Ranked causes

1. Potentiometer wiper not centered on new installation (common)

First check

Verify potentiometer wiper centering after installation

Test point: Potentiometer mid-range
Expected: 2000

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

Calibration: Detector Latch Sensors patient safety

Adjustment of latch sensors on detector #1 to ensure collimator is properly detected as latched. Incorrect latch sensor setting may allow system to continue exchange when collimator is not securely latched.

Ranked causes

1. Latch sensor position not detecting magnet halfway through lock notch (occasional)

First check

Verify latch sensor tone at bottom of lock notch

Test point: Foot-end, front corner of Detector #1 lock plate
Expected: Tone should be on when latch pin is at bottom
Tools: Audible sensor feedback

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

Calibration: Detector Leveling caution

Leveling detector heads to ensure perpendicular orientation and prevent rocking, critical for accurate ECT reconstructions

Ranked causes

1. Detectors not level (common)

First check

Verify Radius Base Plates vertical before leveling detector

Test point: Both detector Radius Base Plates
Expected: Vertical
Tools: Small level

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

Calibration: Detector Leveling initial setup

Initial setup for detector leveling procedures, including gantry rotation and detector positioning

Ranked causes

1. Detector leveling prerequisites not met (common)

First check

Confirm Gantry Rotate calibration complete

Test point: Calibration status display
Expected: Gantry Rotate cal points stored

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

Calibration: Detector Lock Plate Sensors caution

Adjustment of lock plate sensors on detectors #1 and #2 to ensure proper magnet position detection during collimator locking. Sensors must detect magnet locations accurately.

Ranked causes

1. Lock plate magnet off-center (occasional)

First check

Test Detector #1 lock plate sensor unlock position

Test point: Foot-end and head-end lock plates on Detector #1
Expected: Tone should sound when lock plates move to unlock notch
Tools: Audible sensor feedback

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

Calibration: Foot vertical table motion

Encoder and potentiometer synchronization for vertical (Z-axis) motion of patient table foot end.

Ranked causes

1. Potentiometer wiper not centered on new installation (common)

First check

Verify potentiometer wiper centering after installation

Test point: Potentiometer mid-range
Expected: 2000

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

Calibration: Gantry calibration and limit data backup

Back up gantry calibration and limit data from RAM to PC files and floppy disc for disaster recovery.

Ranked causes

1. Routine maintenance and disaster recovery (common)

First check

Access DOS prompt from Acquisition Console

Test point: Main Menu
Expected: DOS prompt accessible via EXIT selection

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

Calibration: Gantry motion

System requires recalibration after potentiometer replacement or U-3 error to set scale factor relating voltage to mechanism position

Ranked causes

1. Potentiometer replaced or U-3 encoder mismatch error (common)

First check

Enable Cal Mode on MPU board

Test point: Cal Mode Rocker Switch (3rd from left on MPU PCB)
Expected: Switch activated

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

Calibration: Gantry Rotate caution

Gantry rotation angle calibration using potentiometer feedback at -180° and +180° positions, verified with level on Radius Base Plate

Ranked causes

1. Gantry 0° and 180° positions not level (common)

First check

Verify Radius Base Plate is vertical at -180° gantry position

Test point: Left detector #1 Radius Base Plate
Expected: Level (bubble centered)
Tools: Small level

3 more checks with pass and fail actions, 8 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Gantry Rotate at initial setup

Initial gantry rotation setup ensuring detectors are properly positioned and not at hardware limits

Ranked causes

1. Gantry not properly initialized before calibration (common)

First check

Confirm detectors are 180° apart

Test point: Detector angular position display
Expected: 180° separation

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

Calibration: Gantry translate

Encoder and potentiometer synchronization for gantry translation (longitudinal movement along acquisition axis).

Ranked causes

1. Potentiometer wiper not centered on new installation (common)

First check

Verify potentiometer wiper centering after installation

Test point: Potentiometer mid-range
Expected: 2000

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

Calibration: Head vertical table motion

Encoder and potentiometer synchronization for vertical (Z-axis) motion of patient table head end.

Ranked causes

1. Potentiometer wiper not centered on new installation (common)

First check

Verify potentiometer wiper centering after installation

Test point: Potentiometer mid-range
Expected: 2000

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

Calibration: Lateral table motion

Encoder and potentiometer synchronization for lateral (X-axis) motion of patient table. Does not apply to Solus model.

Ranked causes

1. Potentiometer wiper not centered on new installation (common)

First check

Verify potentiometer wiper centering after installation

Test point: Potentiometer mid-range
Expected: 2000

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

Calibration: Radius check patient safety

Independent verification that radius calibration has been performed correctly and detectors are properly positioned to prevent collisions during Cardiac 90 & Lock operations or ECT studies.

Ranked causes

1. Radius calibration dimensions out of tolerance (common)

First check

Measure distance between T-square center and detector #1 bucket edge

Test point: Detector #1 bucket edge (distance X)
Expected: Equal to detector #2 measurement within ±1/16 inch inches, ±1/16 inch
Tools: Carpenter's T-square

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

Calibration: Radius Sensors Setting caution

Set radius sensor magnet locations in system RAM. Radius sensors detect magnet positions on radius base plate for accurate detector positioning during automatic collimator exchanges.

Ranked causes

1. Radius sensor magnet locations not stored in RAM (common)

First check

Set Radius #1 sensor magnet location

Test point: Detector #1 radius drive
Expected: System finds and stores magnet location in RAM, reprints RADIUS 1 POS SENS message
Tools: Display panel, Cal rocker switch

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

Carriage park sensor not as expected

Park sensor state is incorrect, preventing normal gantry operation

Ranked causes

1. Carriage park sensor out of correct state (unknown)

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

E-Stop error with red emergency lights remaining on caution

E-Stop error occurs that doesn't involve a collision, causes the red emergency lights on the Display Panel to remain on, and cannot be cleared by pressing the manual override button.

Ranked causes

1. Out-of-range power supply voltages (common)

First check

Measure +9.85V Reference voltage

Test point: MPU board ADC Mux value 0
Expected: 9.87 V, 9.82 to 9.92 V
Tools: Digital voltmeter, oscilloscope

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

Encoder handler timeout

Bit slice code not responding, indicating MPU board failure

Ranked causes

1. Bad MPU board (bit slice code not responding) (rare)

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

Gantry motor belt broken

Motor belt broken, detected by broken belt sensor

Ranked causes

1. Motor belt broken (occasional)

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

Gantry moved opposite to requested direction

Motor moved in wrong direction, indicating wiring issue

Ranked causes

1. Incorrect motor wiring (occasional)

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

Gantry MPU diagnostic tests fail for unexplained reasons

Diagnostic tests on the Gantry MPU board fail without a clear cause.

Ranked causes

1. Out-of-specification power supply voltages (common)

First check

Perform complete voltage sweep on MPU board

Test point: All ADC Mux values 0, 1, 4, 5, 6, 7
Expected: See Table 4-1 for each Mux value
Tools: Digital voltmeter, oscilloscope

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

Gantry MPU replacement with calibration restoration

Restore calibration after replacing Gantry MPU by reloading GANTCAL.DAT and rechecking all calibrations.

Ranked causes

1. Gantry MPU replaced (rare)

First check

Verify GANTCAL.DAT file is available from backup

Test point: Floppy disc archive
Expected: GANTCAL.DAT file readable and intact

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

Gantry Rotate 0° sensor not as expected

Rotation sensor state is incorrect, preventing normal operation

Ranked causes

1. Gantry Rotate 1, 0° sensor out of correct state (unknown)

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

Gantry Rotate 180° sensor not as expected

Rotation sensor state is incorrect, preventing normal operation

Ranked causes

1. Gantry Rotate 2, 180° sensor out of correct state (unknown)

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

Gantry Rotate Clutch Error, Motion Halted

Clutch disconnected or slipped, causing gantry rotation position change >2°

Ranked causes

1. Gantry Rotate Clutch disconnected or slipped (position change >2°) (occasional)

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

Gantry Rotate floating

Ring lock sensor unreadable, causing floating gantry rotation without lock

Ranked causes

1. Ring lock sensor unreadable (unknown)

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

Gantry will not move under Handcontroller commands caution

Gantry does not respond to movement commands sent via Handcontroller.

Ranked causes

1. Out-of-range power supply voltages affecting gantry motor control (common)

First check

Verify +5V supply voltage is within range

Test point: MPU board ADC Mux value 5
Expected: 5.0 V, 4.8 to 5.2 V
Tools: Digital voltmeter

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

Hardware limit reached caution

Gantry mechanism hit physical limit due to negligence in calibration mode or bad calibration/limit sensor

Ranked causes

1. Negligence in calibration mode or bad calibration/limit sensor (occasional)

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

Head #1 collimator lock sensor not as expected

Collimator lock sensor state is incorrect, preventing normal operation

Ranked causes

1. Head #1 collimator lock sensor out of correct state (unknown)

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

Head #1 target sensor not as expected

Target sensor state is incorrect, preventing normal operation

Ranked causes

1. Head #1 target sensor out of correct state (unknown)

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

Head #2 collimator lock sensor not as expected

Collimator lock sensor state is incorrect, preventing normal operation

Ranked causes

1. Head #2 collimator lock sensor out of correct state (unknown)

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

Head #2 target sensor not as expected

Target sensor state is incorrect, preventing normal operation

Ranked causes

1. Head #2 target sensor out of correct state (unknown)

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

Limit checksum failed

RAM checksum failure indicating corrupted limit data requiring reinitialization

Ranked causes

1. MPU board RAM corrupted (limit checksum failed) (rare)

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

NUAC line source fault condition patient safety

NUAC controller detects fault and is inoperable; gantry may reset and study will be interrupted

Ranked causes

1. NUAC controller fault; motor not connected, wiring fault, or bad bias resistor (rare)

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

Potentiometer encoder mismatch

Pot and encoder values do not match, causing calibration error

Ranked causes

1. Bad potentiometer, bad encoder, or bad calibration (unknown)

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

Potentiometer reading out of range

Pot voltage outside valid range, preventing proper position measurement

Ranked causes

1. Potentiometer outside valid range 350-3900 (0-4000 for Table Z) (unknown)

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

Potentiometer slipping

Potentiometer calibration values too close together, indicating slippage or bad calibration

Ranked causes

1. Bad potentiometer or bad calibration (max/min values too close) (occasional)

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

Preprogrammed motion internal error

Internal programming error preventing preprogrammed motion execution

Ranked causes

1. Programming error in preprogrammed motion routine (rare)

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

Radius Drive 1 sensor not as expected

Radius drive sensor state is incorrect, preventing normal operation

Ranked causes

1. Radius Drive 1 sensor out of correct state (unknown)

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

Radius Drive 2 sensor not as expected

Radius drive sensor state is incorrect, preventing normal operation

Ranked causes

1. Radius Drive 2 sensor out of correct state (unknown)

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

Sensors not present

Serial sensor or SAD board is not detected or has failed

Ranked causes

1. Bad serial sensor or SAD board (rare)

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

Software limit hit

Gantry motion exceeds configured software limits, indicating calibration error

Ranked causes

1. Out of calibration (common)

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

Spectrum problems occur during spectrum changes

Spectrum acquisition issues occur, particularly when making spectrum changes; need to monitor PM tube high voltages.

Ranked causes

1. Unstable or out-of-range power supply voltages during spectrum transitions (occasional)

First check

Monitor +15V supply voltage stability during spectrum change

Test point: MPU board ADC Mux value 7
Expected: 15.0 V stable, 14.5 to 15.5 V
Tools: Digital voltmeter or Display Panel monitoring

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

System oscillates before reaching target position caution

Motor oscillates or 'Maytags' around the target position rather than smoothly reaching it.

Ranked causes

1. Max Speed or IR Comp set too high (common)

First check

Observe motor behavior for oscillation around target

Test point: Motor motion near target position
Expected: Motor smoothly approaches and reaches target without oscillation

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

System stalls before reaching target position caution

Motor fails to reach the target position and stops moving before arrival.

Ranked causes

1. Max Speed or IR Comp set too low (common)

First check

Observe motor behavior during motion to target

Test point: Motor motion toward target position
Expected: Motor reaches target position or creeps steadily toward it

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

Test gantry rotation position sensors

Verify GROT 1 and GROT 2 position sensors functioning at 0° and 180° positions

Ranked causes

1. Position sensor verification required (common)

First check

Verify GROT 1 position sensor at 0°

Test point: GROT 1 Position 0 Sensor
Expected: Sensor active at 0° gantry rotation

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

Translate sensor not as expected

Translate mechanism sensor state is incorrect, preventing normal operation

Ranked causes

1. Translate sensor out of correct state (unknown)

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

Unable to lock ring

Ring lock device is not in correct position and is slipping, preventing proper locking

Ranked causes

1. Ring lock device out of position and slipping (occasional)

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

Unrequested motion occurred patient safety

Gantry moved without handcontrol or software command due to loose cables, user extraction, or motor controller failure

Ranked causes

1. Cables loose, user manually extracted patient, or motor controller failed (rare)

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

Unwanted spurious interrupt

System detects unexpected hardware interrupt or internal software bug

Ranked causes

1. Hardware noise or internal software bug (occasional)

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

Verify collimator identification

Read electrical identification number of mounted collimators and verify stability during gantry rotation

Ranked causes

1. Collimator identification check required (common)

First check

Display collimator identification numbers

Test point: Service Mode menu
Expected: Identification numbers of mounted collimators visible

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
`F-25`	Limit checksum failed in MPU board	RAM checksum validation fails on MPU board	critical
`F-81`	Unrequested motion	Gantry motion occurred without handcontrol or software command	critical
`F-92`	Gantry moved opposite to requested direction	Motor moved in wrong direction	critical
`F-94`	Gantry motor belt broken	Broken belt sensor detects fault	critical
`F-99`	Hardware limit reached	Gantry mechanism hit physical limit	critical
`R-1`	Communication error	DUART parity, framing or overrun error	warning
`R-12`	Detector head has improper collimator type and parity	Bad collimator ID tag or improper collimator setup	error
`R-16`	Detector head collision	Physical collision or wiring issue detected	error
`R-18`	Manual override active	Override exists in pre-program or computer mode	info
`R-19`	Axis out of range	PC commanded gantry motion but did not exit motion command	error
`R-2`	Emergency stop	E-stop button pressed	error
`R-21`	Cannot update calibration RAM	Cal switch is off or Cal RAM write attempted without enable	error
`R-22`	Parameter error	PC received command with incorrect parameter	error
`R-23`	Bad checksum in Cal RAM	Cal RAM checksum validation failed	error
`R-24`	Gantry is not paused	Resume sent by PC when gantry was not paused	error
`R-27`	Cal enable switch is off	Attempt was made to write to Cal RAM with Cal switch off	error
`R-29`	Suspend not allowed	Pause from PC not allowed in current operating mode	info
`R-30`	Motion already active	PC attempted to move a motion that was already moving	warning
`R-32`	NUAC shutter not opened	Shutter on specified line source did not open when commanded	error
`R-33`	NUAC: Line source at invalid position	PC tried to move Gantry Rotate #2 relative to #1 when NUAC line sources at incorrect position	warning
`R-38`	NUAC: Line source error - no move setup done	Acquisition station or diagnostic issued move command to NUAC device without preceding setup command	error
`R-39`	Unexpected position sensor state in preprogrammed mode	Sensor malfunction during preprogrammed operation	warning
`R-4`	Exchanger trays not parked	Automatic or manual exchanger out of position; bridge up sensor not set or bad carriage park sensor	warning
`R-40`	Radial map undefined	NCR motion attempted before defining radial map	warning
`R-43`	Radial map bounds error	Radial map caused motion to move outside software limits	error
`R-44`	NUAC: not enabled	NUAC device installed but enable jumper not set	warning
`R-45`	NUAC: Line source error - line source not mounted	NUAC acquisition or preprogrammed command executed when line sources not mounted	error
`R-46`	NUAC: Line source error - line source not parked	Command or preprogrammed option detected line sources not parked, possibly from premature stop	error
`R-47`	NUAC: Line source error - line source shutter not closed	Line source detected open when not commanded to open	error
`R-48`	NUAC: Line source error - wrong line source mounted	System detected wrong line source mounted on at least one head	error
`R-49`	NUAC: Line source error - line source not communicating	Power not getting to NUAC device or communication failure	error
`R-52`	Preprogrammed motion not allowed in Override	Override mode active when preprogrammed motion attempted	warning
`R-53`	Head #1 Rotate out of range for preprogrammed motion	Head Rotate in outer room position during preprogrammed motion	warning
`R-54`	Preprogrammed motion not allowed in current state	System in collision or E-stop state	error
`R-56`	Preprogrammed motion is aborted	User stopped PC-initiated preprogrammed sequence	info
`R-57`	Head #2 Rotate out of range for preprogrammed motion	Head Rotate in outer room position during preprogrammed motion	warning
`R-58`	Head #2 not in position	Head not in position to exit outer room	warning
`R-5A`	Motion not allowed	On Cardio system, gantry motion when detectors at relative 180°	warning
`R-5B`	Direction of movement not allowed	Gantry moved in wrong direction with rings unlocked in diagnostic mode	warning
`R-5F`	Slave motion incomplete	Motion did not reach final position	error
`R-6`	Relative motion error	Slave motion not keeping up with master during simultaneous motion	warning
`R-60`	Motion incomplete	Motion did not reach final position	error
`R-61`	Active motion type change	Software tried to change type of active motion	critical
`R-62`	Slave startup error	Slave and master position mismatch at motion startup	error
`R-63`	Overheat watchdog (Manual Exchanger)	User failed to unlatch collimator within 2 minutes	critical
`R-64`	Table motion not allowed	Fast Table Z attempted when carriage not parked	warning
`R-76`	Collimator locking mechanism not latched	Collimator latch sensor off or collimator latch open	error
`R-77`	Locking plate error	Locking plate sensor not unlocked	error
`R-78`	Detector Head Lock Plate Lock sensor not locked	Lock Pin sensor off or collimator on detector	error
`R-79`	Position sensor not calibrated	During sensor calibration, software could not find sensor	error
`R-8`	Motor power off	Motor power is off for any reason that activates motion halt lights	warning
`R-83`	Head #1 is unlocked	Detector unlocked state	warning
`R-84`	Head #2 rotate is unlocked	Detector unlocked state	warning
`R-85`	Gantry position error	Gantry not at correct position for lock/unlock	error
`R-88`	Motion not allowed	User attempted motion with Cal or limit switch on	warning
`R-91`	Command length error	Gantry received command with unexpected length	error
`R-96`	Mechanical calibration does not agree with sensor	Target sensor not seeing cassette or sensor not working or motion not calibrated	error
`R-a1`	Collimator exchanger motion failure	Collimator exchanger motion did not reach destination	error
`R-a2`	Collimator exchanger latch sensor error	Latch sensor in unexpected state	error
`R-a3`	Collimator exchanger lock sensor error	Lock sensor in unexpected state	error
`R-a4`	Collimator exchanger unlock sensor error	Unlock sensor in unexpected state	error
`R-a5`	Collimator exchanger locking plate sensor not as expected	Locking Plate Lock and Unlock Sensors both off or mismatched state	error
`R-a6`	No collimator ID	ID cannot be read from tag after collimator mounted	error
`R-a7`	Collimator exchanger map error	Collimator map incorrect or sensor not working	error
`R-a8`	Collimator exchanger communication error	Probable noise in communication or not connected	error
`R-a9`	Collimator exchanger is not ready	Elevator position out of range or 2nd pot cannot be read	error
`R-aa`	Collimator exchanger not safe to move	Position or sensor indicates not safe for motion	error
`R-ab`	Collimator exchanger carriage position failure	Carriage position by pot #1 differs from pot #2	error
`R-ac`	Collimator exchanger cannot be parked	Motion not at exchange position for preprogrammed park command	error
`R-ad`	Preprogrammed internal script/sequence error	Internal software error in programmer or sequence	critical
`R-ae`	Preprogrammed time-out	Waiting for display to set override	error
`R-af`	Collimator Exchanger not allowed with brain pallet	Collimator exchange attempted with brain pallet installed	warning
`R-b0`	Sensor not as expected - Head #1 locked in	Head #1 Lock sensor not in correct state	warning
`R-b1`	Sensor not as expected - Head #1 locked out	Head #1 Lock sensor not in correct state	warning
`R-b2`	Sensor not as expected - Head #2 locked in	Head #2 Lock sensor not in correct state	warning
`R-b3`	Sensor not as expected - Head #2 locked out	Head #2 Lock sensor not in correct state	warning
`R-b4`	Gantry rotate 90 lock sensor not as expected	Gantry rotate 90 lock sensor not in correct state	warning
`R-b5`	Gantry rotate 2 180 lock sensor not as expected	Gantry rotate 2 180 lock sensor not in correct state	warning
`R-b6`	Carriage park sensor not as expected	Park sensor not in correct state	warning
`R-b7`	Head #1 collimator lock sensor not as expected	Collimator lock sensor not in correct state	warning
`R-b8`	Head #2 collimator lock sensor not as expected	Collimator lock sensor not in correct state	warning
`R-b9`	Head #1 target sensor not as expected	Target sensor not in correct state	warning
`R-ba`	Head #2 target sensor not as expected	Target sensor not in correct state	warning
`R-bb`	Gantry Rotate 2, 180° sensor not as expected	Rotation sensor not in correct state	warning
`R-bc`	Gantry Rotate 1, 0° sensor not as expected	Rotation sensor not in correct state	warning
`R-bd`	Translate sensor not as expected	Translate mechanism sensor not in correct state	warning
`R-be`	Radius Drive 1 sensor not as expected	Radius drive sensor not in correct state	warning
`R-bf`	Radius Drive 2 sensor not as expected	Radius drive sensor not in correct state	warning
`U-10`	Unwanted spurious interrupt	Unexpected hardware interrupt or internal software fault	warning
`U-14`	Software limit hit	Gantry motion exceeds configured limits	warning
`U-20`	Potentiometer slipping	Max and min calibration values too close together	warning
`U3`	Encoder and potentiometer position out of tolerance	Detected difference between encoder-determined and potentiometer-determined positions exceeds acceptable range	error
`U-3`	Potentiometer encoder mismatch	Pot and encoder values do not match	error
`U-34`	NUAC line source fault	NUAC controller detects fault condition	critical
`U-5`	Potentiometer reading out of range	Pot voltage outside 350-3900 range (0-4000 for Table Z)	error
`U-59`	Gantry Rotate floating	Ring lock sensor unreadable	error
`U-7`	Encoder handler timeout	Bit slice code not responding	error
`U-89`	Gantry Rotate Clutch Error, Motion Halted	Clutch disconnected or slipped (position change >2°)	error
`U-98`	Unable to lock ring	Ring lock device not in correct position	error
`U-a0`	Preprogrammed motion internal error	Internal programming error in preprogrammed motion routine	error
`U-f`	Sensors not present	Serial sensor or SAD board not detected	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.