Upright SB60 Control Instability Electrical Faults and Platform Safety Restoration

[MikePhua]

The SB60 and Upright’s Aerial Work Platform Legacy
The Upright SB60 is a self-propelled boom lift designed for elevated access in industrial, commercial, and maintenance environments. With a working height of approximately 66 feet and a horizontal outreach of over 50 feet, the SB60 was engineered to provide reliable performance in tight spaces and uneven terrain. Its articulating boom and telescopic extension allow operators to reach complex angles, making it suitable for facility maintenance, signage installation, and steel erection.
Upright, originally founded in the UK, was known for its compact scissor lifts and boom platforms before merging with Snorkel in the mid-2000s. The SB60 was one of its flagship models, combining hydraulic simplicity with electronic control logic. Though production ceased years ago, many SB60 units remain in service globally, especially in rental fleets and industrial plants.
Terminology Annotation:

• Articulating Boom: A lift arm with multiple joints that allows flexible movement around obstacles.
  
• Telescopic Extension: A straight boom that extends linearly to increase reach.
  
• Self-Propelled Platform: A lift that can drive and steer under its own power while elevated.
  

Erratic Control Behavior and Safety Implications
Operators have reported issues with the SB60’s controls behaving unpredictably—such as sudden jerks, delayed response, or unintended movement. These symptoms pose serious safety risks, especially when working at height or near sensitive structures.
Common manifestations include:

• Boom drift or twitching during extension
  
• Platform rotation without input
  
• Drive motors engaging erratically
  
• Control panel lights flickering or resetting
  
• Audible relay clicks without function activation
  

Such behavior often stems from electrical faults, including:

• Loose or corroded connectors in the control box
  
• Grounding issues affecting signal stability
  
• Faulty joystick potentiometers
  
• Moisture intrusion into relays or logic boards
  
• Voltage drops due to aging batteries or wiring fatigue
  

In one maintenance facility in Ohio, an SB60 began rotating the platform without joystick input. The cause was traced to a cracked solder joint on the control board. After reflowing the joint and resecuring the harness, the issue was resolved.
Control Box Inspection and Wiring Integrity
The SB60’s upper control box houses the joystick, toggle switches, and diagnostic indicators. It communicates with the lower control module via a multi-core cable. When controls become erratic, this interface is the first place to inspect.
Diagnostic steps:

• Open the control box and inspect for moisture, corrosion, or loose terminals
  
• Test joystick output voltage (typically 0–5V range) for smooth response
  
• Check continuity across the main harness using a multimeter
  
• Wiggle connectors while monitoring voltage to detect intermittent faults
  
• Clean all contacts with electrical cleaner and apply dielectric grease
  

Terminology Annotation:

• Potentiometer: A variable resistor used to measure joystick position and translate it into voltage signals.
  
• Continuity Test: A check to determine if electricity can flow through a wire or switch.
  
• Dielectric Grease: A non-conductive lubricant that prevents corrosion on electrical contacts.
  

In one rental fleet in Alberta, erratic boom movement was resolved by replacing the joystick potentiometer and reseating the main connector with new pins.
Relay and Logic Board Reliability
The SB60 relies on relays to activate hydraulic valves and drive motors. These relays are controlled by the logic board, which interprets joystick and switch inputs. Over time, vibration, heat, and oxidation can degrade relay performance.
Recommendations:

• Replace relays every 2,000 hours or during major service
  
• Use relays rated for vibration and outdoor use (IP65 or higher)
  
• Inspect solder joints on the logic board for cracks or cold joints
  
• Mount the board securely to reduce vibration stress
  
• Keep the enclosure sealed and dry with desiccant packs if needed
  

Terminology Annotation:

• Cold Joint: A solder connection that appears intact but lacks proper electrical conductivity.
  
• IP65 Rating: A standard indicating protection against dust and low-pressure water jets.
  
• Desiccant Pack: A moisture-absorbing pouch used to keep enclosures dry.
  

In one industrial site in Texas, a platform rotation fault was traced to a relay that had oxidized internally. Replacing the relay and resealing the enclosure restored full control.
Battery Health and Voltage Stability
Even though the SB60 is engine-powered, its control system relies on stable voltage from the battery. Low voltage can cause logic errors, relay chatter, and signal dropout.
Preventative measures:

• Test battery voltage under load (should remain above 11.5V)
  
• Replace batteries every 3–4 years or when capacity drops
  
• Clean terminals monthly and apply anti-corrosion spray
  
• Use a voltage monitor in the control box to alert operators
  
• Avoid jump-starting without verifying system voltage
  

Terminology Annotation:

• Relay Chatter: Rapid clicking of a relay due to unstable voltage or signal.
  
• Voltage Dropout: A sudden loss of electrical power that disrupts control logic.
  
• Anti-Corrosion Spray: A protective coating that prevents oxidation on metal surfaces.
  

In one warehouse in Oregon, erratic drive behavior was resolved by replacing a sulfated battery and installing a voltage stabilizer.
Operator Training and Emergency Protocols
Erratic controls demand clear operator protocols. Recommendations include:

• Train operators to recognize control anomalies and stop operation immediately
  
• Keep a laminated fault checklist in the cab
  
• Install an emergency stop button within easy reach
  
• Document all control faults and repairs for trend analysis
  
• Perform monthly function tests on all control inputs
  

In one airport maintenance crew in Florida, implementing a pre-shift control test reduced unexpected faults and improved operator confidence.
Conclusion
The Upright SB60 remains a capable aerial platform—but erratic controls can compromise safety and productivity. By inspecting electrical connections, maintaining voltage stability, and replacing aging components, operators can restore smooth and predictable performance. In elevated work, control is everything—and the SB60 demands attention to every wire, relay, and signal to keep its reach reliable.