Surgical lights

DRE Medical MI-750: troubleshooting and error codes

The ServiceForge knowledge base holds 24 documented symptoms for the DRE Medical MI-750, with 37 ranked causes, 37 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

Light will not turn on or stay on caution

Surgical light fails to illuminate or will not remain illuminated when powered

Ranked causes

1. Power to unit is off (common)
2. Blown fuse (common)
3. Wire assembly damaged or cut (occasional)
4. Wire connections incorrect during installation (occasional)
5. Wire connections disconnected after installation (occasional)
6. No input power to light unit (occasional)
7. Disconnected wires at switch or PSU (occasional)
8. No power output from PSU with input power present (occasional)
9. Wire connections reversed (rare)
10. Sterilizable handle button not engaging power switch properly (occasional)

First check

Verify light is plugged in and power is on

Test point: power outlet/main switch
Expected: unit is connected and switched on

6 more checks with pass and fail actions, 10 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Light does not maintain horizontal position caution

Light arm drifts or does not stay level horizontally due to bracket misalignment or loose fasteners

Ranked causes

1. Mounting bracket not level (common)
2. Pivot bolt fasteners loose (common)

First check

Check mounting bracket level

Test point: mounting bracket attachment points
Expected: bracket is level
Tools: spirit level

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

Light does not maintain vertical position caution

Light arm droops or does not stay in desired vertical position due to spring or added weight

Ranked causes

1. Incorrect spring tension (common)
2. Additional equipment added to arm (occasional)

First check

Check spring tension adjustment

Test point: light arm spring mechanism
Expected: spring tension sufficient to support light position

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

Light output is irregular in shape or intensity

Surgical light output is uneven, dim in patches, or has inconsistent brightness

Ranked causes

1. Input voltage does not correspond to rating label (occasional)
2. Light head is not mounted on proper arm (Combo models) (occasional)

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

Upright rotates in floor stand patient safety

Upright post rotates or spins within the floor stand assembly

Ranked causes

1. Upright set screw is loose (common)
2. Upright is not fully seated on anti-rotation pin (common)

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

Arm cannot be moved any lower

Surgical arm will not extend downward beyond current position

Ranked causes

1. Arm is against internal stop (common)

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

Arm cannot be raised any higher

Surgical arm will not extend upward beyond current position

Ranked causes

1. Arm is against internal stop (common)

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

Arm droops excessively caution

Arm does not maintain position and droops under its own weight despite brake being set

Ranked causes

1. Brake tension set too loose (common)

First check

Verify spring tension adjustment is correct

Test point: Arm vertical travel at current brake setting
Expected: Arm with loose brake travels equal distance up/down with same force

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

Arm droops excessively when brake loosened

Arm drops freely after friction brake release, indicating expected behavior during tension adjustment

Ranked causes

1. Friction brake released for spring adjustment (common)

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

Arm stopped moving horizontally

Surgical arm will not move left or right

Ranked causes

1. Arm is against internal stop (common)

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

Articulating arm drifts from original position

The arm does not stay in the adjusted position and returns to a different location

Ranked causes

1. Arm adjustment out of specification (common)

First check

Verify articulating arm positions and holds at adjusted location

Test point: Articulating arm
Expected: Arm remains in adjusted position without drifting

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

Calibration: Arm friction and tension adjustment caution

Arm droops excessively or requires excessive force to position; factory pre-adjustment needs refinement

Ranked causes

1. Arm friction brake and spring tension require adjustment (occasional)

First check

Release arm friction brake

Test point: Set screw in Friction Adjustment Hole
Expected: Arm droops freely when brake is loosened
Tools: Allen wrench

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

Calibration: Arm tension adjustment caution

Arm droops or does not hold position; requires spring tension and friction brake adjustment to achieve balanced vertical travel

Ranked causes

1. Arm spring tension out of adjustment (unknown)

First check

Loosen friction brake set screw inside Friction Adjustment Hole

Test point: Set screw in Friction Adjustment Hole
Expected: Loosened 3-4 turns; arm droops freely

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

Caster/casters cannot be reinstalled

Floor base casters cannot be reattached or installed properly

Ranked causes

1. Floor base has been damaged (occasional)

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

Fuse blown high voltage

Unit loses power or circuit protection activates

Ranked causes

1. Fuse failure or overcurrent condition (unknown)

First check

Verify power cord is disconnected

Test point: Power outlet connection
Expected: Power cord unplugged

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

Fuse blown or unit loses power high voltage

Unit does not power on or power is lost after operation; fuse holders located in top cover of cylindrical enclosure at end of arm.

Ranked causes

1. Blown fuse requiring replacement (common)

First check

Verify power cord is disconnected from supply outlet

Test point: Power supply connection
Expected: Power disconnected

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

Fuse replacement required high voltage

One or more fuses have blown in the surgical light arm enclosure, requiring replacement before operation can resume.

Ranked causes

1. Blown fuse in cylindrical arm enclosure (unknown)

First check

Verify power cord is disconnected

Test point: Power outlet connection
Expected: Power cord unplugged

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

LED dim or off

One or more LEDs generate noticeably dim light output or are completely off

Ranked causes

1. LED failure or degraded output (rare)

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

LED is off or noticeably dim

One or more LEDs produce no light or significantly reduced light output

Ranked causes

1. LED degradation at end of service life (unknown)

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

LED output dim or off

One or more LEDs are not illuminating or producing noticeably reduced light output from the surgical light.

Ranked causes

1. LED end-of-life or failure (L70 threshold reached or exceeded) (rare)

First check

Verify LED illumination status and brightness

Test point: LED array in light head
Expected: All LEDs illuminated at full brightness

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

LED(s) off or dim

One or more LEDs are not illuminating or produce noticeably reduced light output

Ranked causes

1. LED(s) end of life or defective (occasional)

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

Light head will not rotate at yoke interface

Light head cannot be rotated at the connection point between head and arm

Ranked causes

1. Light head is against internal stop (common)

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

One or more LEDs off or dim

LED not illuminating or producing noticeably dim light output

Ranked causes

1. LED failure or degradation (unknown)

First check

Verify LED operation status

Test point: Visual inspection of all LEDs in light head
Expected: All LEDs illuminated at normal brightness

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

Unit fuse blown high voltage

Fuse(s) in the cylindrical enclosure arm end require replacement to restore power

Ranked causes

1. Fuse(s) open or blown (unknown)

First check

Visually inspect fuse element

Test point: Fuse in cylindrical enclosure arm end
Expected: Fuse element intact, no visible break or blackening

1 corrective action and part numbers 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.