If the knives do not close all the way, then the black component will not be under the sensor above it. Anyway this black component is part of the trim sensor, in that when the knife opens the black component moves to the left away from the sensor, when the knives close, this same component moves to the right as it is also attached to the same thin silver shaft that the silver knives are connected to. This black component sort of resembles a tall black screw with some hex bolts on it. If you were to follow that thin shaft to the right as if you were looking from the back of the machine, you will see a black component that will probably have an LED light attached to the top of it. When the plunger gets fired up into the cam, both knives move in unison by way of them being connected to that thin silver shaft. Now as I have mentioned both silver moving knives are connected to a linkage on a thin silver shaft behind the machine and under the table.
The plunger once fired upwards into the cam then follows the groove as the cam spins, this is what makes the silver moving knife under the needle plate open, At the time the cam has made a full rotation, the plunger as it is called (Smaller chrome colored shaft) falls back into its steel casing, and readies itself for the trim solenoid to fire it upwards into that cam again on the next trim command. When the machine issues a trim command, their is a smaller chrome colored shaft on the right hand side of the machine under the table, that gets fired upwards into a cam that has a groove cut out of it, This smaller shaft is called the PLUNGER, The plunger gets fired upwards by the Trim solenoid. All the heads silver knifes are secured to a linkage, which is attached to a thin chrome colored shaft in the back of the machine. If you had a birds nest occur on one of the heads, then you need to swing the knife out from under that black piece and look for any thread or any debris caught under the black piece which would disallow the silver knife to fully seat under that black piece. When the machine executes a trim the silver knife swings out from under the small black piece which has the SWF logo engraved on it, the silver knife then collects the upper thread and the bobbin thread and pushes it under the black piece which does all the trimming. Remove the needle plates from the machine and you will find that under those needle plates are your knives for your trimmer.
Let me explain how your trimming system works, that way you will have a better understanding how to correct this. All of the heads on a Multi Head Machines trimming assembly are connected together and are not independent. 1) You had a birds nest occur on one of the heads and when the knife tried to do a trim, the silver knife under the needle plate was able to fully open and then could not go back under the black piece.ΔΆ 2) Grease has accumulated on the plunger and will not recess back to its original position to be able to fire again on the next trim command. Why is thread not trimming on my multi head? Error 103 An Error 103 indicates that the knives did not return to their start position. 7) The last tension adjustment you want to make is to the main tension.
6) Next, you want to make sure the pre-tension is adjusted correctly.
5) Once the bobbin case is clean, reinsert the bobbin and ensure the tension is correct. 2) Remove the bobbin and case from the rotary hook. To do this, you will probably have to cut away all of the nested thread with a pair of scissors. Steps 1) Remove the excess thread from underneath the needle plate. Bird nesting typically occurs when the bobbin is not set properly: whether the tension is incorrect, the bobbin case is dirty, or the bobbin is not properly placed in the case. The most common occurrences of these errors are caused by having thread caught in the hook area, commonly referred to as a "Bird's Nest". 1 What are ERRORS 101 AND 102 (Main Board and Overload) and how to resolve it.