Below is information on how to trouble shoot issues that may happen, with your knitting machine, and you always do have issues.  That way you can try to figure it out what is going on yourself before sending it in for repairs.  I found this information on line at the Knitting Closet. With that said, I would discourage you from taking apart the knitting carriage unless you know what you are doing, I did this and created a mess.

"Make your Knitting Machine Sing"
One book that is a must have for all machine knitters is Make your Knitting Machine Sing.  It is the best book out on the market to make sure your knitting machine runs like a dream.  Just google it as many places sell it like DK Knits for around $23 and AMAZON for about $26.

In addition to the information below, I have information on how to properly align your knitting machine with your ribber which is one of the most important things you can do for successful double bed knitting.  If this is not done correctly, even if everything else is ok, you will get dropped stitches or other issues.  The pamphlet shows both Brother/KnitKing and Silver Reed/Studio knitting machine main bed and ribber alignment.

                        
How to Align your Ribber Properly
                                 (both Silver Reed/Studio and Brother KM.'s)

                                                 
Brother Chunky Ribber Adjustment
                                                                   
Brother Standard Ribber Adjustment
        
In addition here is an article from Machine-Knitting.net that explains how to trouble shoot your Brother KH930 Knitting Machine that will not turn on or has a no power fault issue:
                                                                         
Brother KH930 won't turn on white paper


What you can do on a Regular Basis 

  • Clean and Lubricate regularly and be sure to use only "Knitting Machine Oil" - do not use sewing machine oil or WD-40
  • examine magnets for attached debris
  • examine brushes for yarn or strings caught - remove yarn 
  • examine for loose or broken parts 
  • examine for loose screws
  • replace needle presser bar (sponge bar) every couple of years - clean bar track also using long cattail/rattail brush - especially if using home spun yarns!
  • replace worn brushes as needed - remove brushes and remove lint and/or yarn from under brush journal shaft
  • replace worn, bent or broken needles - check needle presser bar (sponge bar) for wear every 3 months.

What you should not do to your Knitting Machine 

  • do not dig into needle bed track 
  • do not set carriage down on metal opbject 
  • do not try to force jammed carriage 
  • do not change carriage settings in mid row. 
  • do not attempt to disassemble carriage 
  • do not attempt to disassemble punch card or mylar reader mechanisms
  • do not use sewing machine oil or WD-40 

Dropped Stitches 
•    First check your needle retainer bar(sponge bar to most of us) to make sure it is not compressed or damaged.  Replace if foam is not at least 3/8 inch above metal backing. 
•    Every row - same spot 

  • Bent needle at knee 
  • Bent, sticky or broken latches 
  • Card punched wrong 
  • Bent gate pegs 

•    Random Locations 

  • Feeder plate adjustment, 
  • Antenna (tension spring) setting incorrect 
  • Needle latches missing, bent or broken
  • Yarn Threaded wrong

•    Now and Then 

  • Yarn threaded wrong 
  • Yarn hang up from cone 
  • tension pulling too tight 
  • 2nd antenna wire (tension spring) not hooked up 
  • Worn needle presser bar 
  • Too few weights or possibly hung in wrong spot 
  • Trying to make lace on end needle 
  • Knitting with too tight garment tension


Carriage hanging up or hard to push 

  • Lack of lubrication 
  • loose fabric presser assembly (carriage not seated properly) 
  • worn or damaged needle guides in carriage
  • Worn or damaged needle slots in machine bed (needle tracks) 
  • damaged or broken tripper lever 
  • broken tripper lever springs  
  • yarn under carriage brushes (or caught in carriage mechanism)  
  • worn needle presser bar (sponge bar) 
  • metal derbis stuck to magnets
  • cast on too tight
  • yarn tensions too tight
  • If your machine has roller balls, they need lubrication


Drops work off in lap while knitting 

  • color button on - no 2nd yarn in feeder
  • yarn not threaded properly in feeder 
  • no yarn in yarn feeder 
  • yarn too loose with tension on mast or stitch dial
  • cast on too loose
  • yarn broken while knitting the row

                                                        

A Place for Knitting Machine Enthusiasts

Machine Damage - common problems 
•    Main Bed - look for the following 

  • needle track damage (infrequent cleaning and/or lubrication) 
  • sinker post bent (dropped machine - Improper handling of machine) 
  • internal machine problem (infrequent cleaning and/or lubrication) 
  • broken needle in bed (needle presser bar (sponge bar) worn or torn 
  • dropped stitches (needle presser bar worn or torn (sponge bar) 

•    Main Carriage 

  • needle guides or mechanism bent or not working properly (dropped carriage) 
  • broken cams, wheels or guides (infrequent cleaning and/or lubrication), possibly dropped carriage. 
  • buttons do not work independently of each other (especially some Brother models) - (infrequent or improper cleaning and/or lubrication) 
  • broken springs (older machine - possibly metal fatigue) 
  • sticky cams - (infrequent cleaning and/or wrong lube or no lube) Do not use WD-40 - using WD-40, sewing machine or similar lube other than knitting machine oil will RUIN your machine and making it unrepairable. 
  • lack of symmetry in levers  (possible dropped carriage damage or infrequent cleaning and/or lubrication)

•    Lace Carriage  

  • presser wheels bent (damaged - possibly dropped carriage) 
  • presser wheels pushed in too far (older machine - possible rubber or metal fatigue) 
  • worn or damaged wheels or guides (older machine - possibly rubber or metal fatigue)

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Trouble Shooting Simple Issues

​UPDATED 11/2016

Faulty Pattern Selection 
•    Same place every row 

  • bent needle 
  • bent latch 
  • card punched wrong 
  • card not feeding properly

•    Random 

  • failure to select pattern properly 
  • internal machine problem 
  • tension too tight 
  • bent latches 
  • worn needle presser bar (sponge bar) 
  • excessive knitting speed. SLOW DOWN!

Looping 
•    One side only 

  • worn or frayed brush 
  • fabric presser (carriage) out of adjustment 
  • yarn wrapped around a brush 
  • carriage travel excessive 
  • weaving brush left on. 
  • worn needle presser bar (sponge bar)

•    Both sides 

  • worn or frayed brush 
  • weaving brushes left on 
  • yarn or lint under brushes 
  • fabric presser (carriage) out of adjustment 
  • carriage travel too excessive 
  • inadequate yarn tension 
  • yarn hang up in yarn path 
  • yarn not threaded properly 
  • antennae (tension spring) not pulling up slack in yarn (yarn too heavy?) 
  • short antennae (tension spring) not hooked in 2nd color 
  • worn needle presser bar (sponge bar)