Skip to main content

General Troubleshooting Guide

View PDF

General Troubleshooting Guide

When a rip saw or related woodworking machine stops running correctly, effective woodworking machinery troubleshooting starts with isolating where the problem lives — the electrical and power systems, the feed bed, the CamLock tooling, or the cut quality fundamentals. This general guide covers the issues common to Mereen-Johnson rip saws across models, organized in the order an experienced technician would diagnose them. For machine-specific guidance, see the model-specific troubleshooting guides linked throughout and at the bottom of this page.

Safety first: Always disconnect the main power supply before servicing the machine. Unevenly surfaced or bowed material can cause serious personal injury — confirm material condition before ripping.

For a complete downloadable reference, you can also view the full General Troubleshooting Guide PDF.

Operations: Arbor Motor Fails to Start

When the machine has power but the arbor motor won’t start — or has no power at all — work through these causes in order. Most “dead machine” calls trace back to a tripped disconnect, blown fuse, open door interlock, or lubrication/air cutout rather than an actual component failure.

Probable Cause: No Power to the Saw

  • Main power disconnect may be off: Check the disconnect switch on the main Buss line
  • Fuses pulled or blown: Check the disconnect box; replace blown fuses with ones of the same size
  • Overload in the main starter cabinet: One or more starters may be tripped. The overloaded starter displays a flag and its reset button pushes in with resistance. Push the manual reset. (Newer machines have one reset button; some state codes require automatic resets that reset once heater relays cool)
  • Control circuit breaker (110V) tripped: Reset the breaker on or near the main control transformer (see your schematic for location)

Probable Cause: Arbor Access Door Interlock Not Made

Motors won’t start if the doors are ajar. Make sure access doors are properly closed and securely latched, and check whether the switches are loose.

Probable Cause: Lubrication, Air, or Overload Issues

  • Low oil in oil mist generators actuates the low-level cutout. Fill the system per the Oil Mist Lubrication notice on the machine
  • Low or no air pressure: Check the compressed air supply line. With system air present, increase the press roll air pressure until the arbor motor starts — minimum 20 PSI
  • Feed drive frequency control interlock not working: Check input voltages to the controller (main voltage must be present)
  • Tripped overload: Reset the arbor overload switch and the feed overload switch
  • Master control relay not energized: Check the electrical schematic for system control operations

Operations: Feed Bed Fails to Run

  • Arbor motors not running: Start the arbor motors first — the feed bed won’t run if the arbor isn’t running
  • Feed variable frequency drive tripped: Reset the feed VFD per the Maintenance Section
  • Low oil in oil mist generators: Fill the system per the machine instructions

Operations: Feed Bed Does Not Run Smoothly

A rough-running feed bed almost always traces back to lubrication delivery problems or sawdust buildup. Always disconnect main power before servicing.

Probable Cause: Dry Chains or Oil Mist Problems

Extended feed chain pins and bottom vees are dry — check the oil mist generator. Reposition nozzles so one sprays on the bottom of the chain and the other on the extended pins. Clean blocked nozzle ends and check alignment before start-up. Replace a defective oil mist generator.

Probable Cause: Sawdust Buildup

  • Dip cam area: Remove and clean the dip cams
  • Feed sprocket teeth and chain center link: Remove several feed slats from the outfeed end near the feed sprockets, then inspect and clean the hardened dust buildup
  • Blow down the machine daily with compressed air to reduce sawdust buildup

Probable Cause: Worn Dip Cams, Feed Chains, or Coupling

  • Dip cams can be switched side-for-side once; after that, install new cams (keep the spacers). Order new dip cams from Mereen-Johnson Customer Service
  • Feed chains: Replace or rebuild when pins measure less than .450″ from the flat to the opposite side
  • Worn roller chain coupling on the feed motor: Replace, adjust, and lubricate with roller chain oil
  • Unstable frequency controller: Consult the controller manufacturer’s manual

CamLock Collar Moves

The CamLock system holds blade position on the arbor (on moving-blade Select Rip Saws). When a CamLock collar moves, work through these causes:

  • Wrong orientation: The cam should be on the arbor motor side with the lobe toward the outfeed when on the top side of the arbor
  • Bent shoulder bolt: Replace it
  • Infeed system steering material: Make sure the infeed feeding system is aligned properly and jumped up off the part before it enters the saw blade
  • Oil on the arbor: The CamLock mounting area must be clean and oil-free for proper operation
  • Moving saw stop not set: The moving saw hits the CamLock and moves it — set the moving saw stop
  • Outfeed table at wrong height: Adjust the outfeed table or take-away system to the correct level
  • Pressure head setting too low: Reset per the Operations Section
  • Worn tooling with no side clearance: Replace tooling

Cut Quality: Bow Cuts

When the machine produces bowed cuts (curved instead of straight rips), work through these causes:

  • Worn slat inserts: Replace them, and check the press roll adjustment to prevent material slippage
  • Bent aluminum feed slats: Install new Mereen-Johnson feed slats (call Customer Service for pricing)
  • Press rolls out of adjustment: On air-loaded models, check the air regulator functions and settings
  • Infeed/outfeed conveyors influencing feeding: Realign and relevel — the infeed conveyor speed must match the rip saw feed speed exactly
  • Bowed material: Turn the concave side toward the guide so the material is forced against the guide as it feeds
  • Bent feed slats from excessive holddown or thick material: Ensure material is of uniform thickness

Cut Quality: Tapered Cuts

Tapered cuts (one end wider than the other) usually trace back to unevenly surfaced material. Material that’s unevenly surfaced side-to-side causes the high areas to hold the press rolls up off the thinner areas, making the thinner ripped pieces float sideways. Make sure material is evenly surfaced before ripping.

Danger: Unevenly surfaced material can cause serious personal injury. Confirm material condition before ripping.

Cut Quality: Poor Quality of Cut

When overall cut quality has degraded, work through these causes:

  • Saw kerf cuts in the bed plate too wide: Install sharp tooling (contact Customer Service about new tooling) and/or install a new bed plate
  • Press roll to bed plate relationship incorrect: Refer to the Press Roll and Bed Plate sections of the manual
  • Arbor motor bearings failing: Install new motor bearings per the Arbor Motor Section
  • Slip-off bearing fails: Install a new slip-off bearing
  • Non-MJ infeed pinch roll feeder set wrong: Adjust the infeed pinch roll to jump up before the material hits the saw blade

Electrical: Emergency Light Is On

If any Emergency Stop pushbutton is pushed in and the red Emergency Stop light is on:

  • Tripped overload on any starter: Reset the tripped overload
  • Arbor access door ajar or open: Close and lock securely
  • Control Relay Master (CRM) not working correctly: Check system integration for other inhibiting devices or controls

Electrical: Main Power Issues

If main power is on, all Emergency Stops are pulled out, and the lights are off:

  • Incoming power may not actually be on — use an AC voltmeter to verify
  • A fuse near the control transformer may be blown — replace with a proper-size fuse

If the arbor doesn’t start when the arbor pushbutton is pressed:

  • Low Air Main Switch triggered: Check the air supply and lines
  • Low Lube Switch triggered: Fill the oil reservoirs
  • Emergency Stop pushbutton is in: Check for a fault on the feed drive

Electrical: E-Stop Light Comes On for No Apparent Reason

If the machine stops for no apparent reason and the E-Stop light comes on:

  • Check the air pressure, plus the oil level and air pressure of the oil mist generator
  • Check for overloads that have tripped on any of the starters
  • Check for a fault on the feed drive

Machine-Specific Troubleshooting Guides

This general guide covers issues common across Mereen-Johnson rip saws. For troubleshooting specific to your machine, see the model-specific guides:

Related Maintenance and Reference Guides

Still Can’t Resolve the Issue?

If you’ve worked through the relevant section above and your machine still isn’t running correctly, our factory service team can help. Mereen-Johnson technicians have hands-on experience with every machine we’ve built and maintain the original manufacturing records and parts inventory — which means we can diagnose issues other service providers can’t and source exact-fit replacement parts.

Contact Mereen-Johnson service or call (612) 529-7791 to speak with a factory technician.