Blog
Industry insights, buying guides, and expert tips on used rotary drilling rigs.
Rotary Drilling Rig Crowd Cylinder Would Not Move: Isolating a Failed KA4 Relay
A field case showing how function comparison, pressure checks, valve and seal inspection, and changeover-circuit tracing isolated a failed KA4 relay.
Rotary Drilling Rig Mast Leveling Had No Response: Tracing a Worn Balance-Valve Spool
A field case showing how electrical, calibration, valve-spool, and port checks traced a no-response mast-leveling fault to a worn balance-valve spool.
SANY SR280 Main Winch Was Slow in Both Directions: Tracing Low Pilot Pressure
A Guangzhou field case showing how pressure tests traced slow SR280 main-winch lifting and lowering to low pilot pressure at the pilot-pump relief valve.
Rotary Drilling Rig Mast Drifted While Parked: Diagnosing Internal Cylinder Leakage
A field case showing how static hold tests and balance-valve port checks traced gradual rotary drilling rig mast drift to a damaged cylinder seal.
Rotary Drilling Rig Tracked to One Side: Isolating a Sticking Travel-Valve Spool
A field case using pressure checks and controlled left-right circuit swaps to trace travel deviation to a sticking main-valve spool.
Rotary Drilling Rig Hydraulic Oil Overheated: Tracing the Fault to Contaminated Oil and Filters
A field case showing how cooler, fan, drive, belt, bypass-valve, and oil-condition checks traced hydraulic overheating to contaminated oil and filters.
Rotary Drilling Rig Would Not Start: Diagnosing an F15 Fuse and ECM Output-Circuit Fault
A field case showing how circuit isolation, output testing, and harness inspection traced a no-start condition and repeated F15 fuse failure to an ECM output fault.
Rotary Drilling Rig Lost Swing in One Direction: Tracing a Shorted Solenoid Circuit
A field case showing how normal pilot pressure, directional comparison, and solenoid-circuit testing traced a one-direction swing fault to shorted wiring.
Rotary Drilling Rig Would Not Travel: Isolating a Failed Pilot Solenoid Coil
A field diagnosis that compared hydraulic functions and traced a complete loss of travel to a failed travel pilot-solenoid coil.
Rotary Drilling Rig Depth Reading Jumped Unexpectedly: Diagnosing a Failed Shaft Encoder
A field case showing how wiring checks and controlled component substitution traced an unstable drilling-depth display to a failed shaft encoder.
Rotary Drilling Rig Crowd Pressure Was Weak and Slow: A Broken Balance-Valve Spring
A hydraulic field case tracing weak, slow crowd-pressure movement to a broken relief spring inside the crowd-cylinder balance valve.
How a Cracked Rotary Drilling Rig Mast Was Replaced: A Controlled Field Procedure
A source-based field case showing how a cracked rotary drilling rig mast was removed and replaced using two cranes, controlled disconnection, contamination protection, and final function testing.
SANY SR150 Engine Running but the Machine Would Not Move: Diagnosing a Worn Pump Coupling
A field repair case showing how zero hydraulic pressure and a working pilot-solenoid command led technicians to a worn engine-to-pump coupling on a SANY SR150.
Rotary Drilling Rig Depth Reading Moved in Only One Direction: A Signal-Circuit Diagnosis
A field case showing how technicians isolated a rotary drilling rig depth display that changed in only one direction and restored the proximity-switch signal wiring.
Rotary Drilling Rig Main Winch Kept Crushing Wire Rope: Finding the Hidden Drum Misalignment
A rotary drilling rig repair case tracing repeated main-winch wire-rope damage to eight broken end-bearing retaining bolts and drum misalignment.
SANY SR220C Would Not Start: Diagnosing a Repeated F15 ECM Fuse Failure
A field repair case showing how a repeated F15 ECM fuse failure on a SANY SR220C was traced to incorrect preheat-relay connector wiring.
Rotary Drilling Rig Display Went Black During Starting: A Burned Relay Connection Case
A real rotary drilling rig repair case in which a display blackout and no-start condition were traced to a burned starter-relay connection.
SANY Rotary Drilling Rig Mast Cylinder Would Not Retract: A Sequence Valve Diagnosis
A field repair case showing how technicians isolated a SANY rotary drilling rig mast-cylinder fault and traced it to a failed sequence valve.
Used Rotary Drilling Rig Electrical Inspection: 7 Checks Before You Buy
Learn seven practical checks for the electrical and control system of a used rotary drilling rig, including starting, displays, wiring, sensors, safety interlocks, and test evidence.
How to Inspect a Used Rotary Drilling Rig Chassis: 5 Critical Systems Buyers Should Check
A practical five-system chassis inspection guide for overseas buyers evaluating a used rotary drilling rig before purchase and shipment.
SANY SR280RC Main Winch Motor Fracture: Failure Analysis and Preventive Measures
A field case analysis of a fractured SANY SR280RC main-winch motor, covering damage evidence, probable shock-load causes, and preventive measures.
SANY SR280 Main Winch Running Slowly: Hydraulic Diagnosis and Repair
A field repair case explaining how low pilot pressure caused slow hoisting and lowering on a SANY SR280 rotary drilling rig, including pressure tests, diagnosis, adjustment, and results.
How to Buy a Quality Used Rotary Drilling Rig from China
A practical guide for global contractors buying used rotary drilling rigs from China, including brand selection, SANY vs XCMG, inspection tips, and supplier checks.