Welcome To SIRUBA

◎ The needle thread is not tight enough.

Check：

Is the needle thread tension too weak, or is the lower thread tension too strong?

Adjustment：

Adjust the needle thread tension or lower thread tension.

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◎ The lower thread is not tight enough.

Check：

Is the lower thread tension too weak, or is the needle thread tension too strong?

Adjustment：

Adjust the lower thread tension or needle thread tension.

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◎Loops appear in seam.

Check：

Is the thread path not smooth enough?

Adjustment：

Use sandpaper to polish smooth the thread path.

Check：

Is the bobbin not turning smoothly?

Adjustment：

Pull out the lower thread to check that there is no slackness in the thread tension, or replace the bobbin or bobbin case.

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◎ Skipping stitches occur while sewing.

Check：

Is the needle tip bent? Is the needle tip blunt?

Adjustment：

If the needle tip is bent or broken, replace it.

Check：

Is the needle properly installed?

Adjustment：

If it is incorrect, install the needle correctly.

Check：

Is the machine properly threaded?

Adjustment：

If it is incorrect, thread the thread correctly.

Check：

Is the presser foot pressure too weak?

Adjustment：

Adjust the presser foot pressure.

Check：

Is the needle too thin?

Adjustment：

Replace the needle with a needle that is one rank thicker.

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◎ Skipping stitches occur while sewing.

Check：

Is the presser foot too high?

Adjustment：

Adjust the presser foot height.

Check：

Is the thread take-up spring tension too weak?

Adjustment：

Adjust the thread take-up tension.

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◎ Skipped stitches or unraveled thread at sewing start.

Check：

Is the thread take-up spring tension too strong?

Adjustment：

Reduce the tension of the thread take-up spring.

Check：

Is the thread take-up spring operating range too large?

Adjustment：

Lower the position of the thread take-up spring.

Check：

Are the trailing lengths of the needle threads too short after thread trimming?

Adjustment：

Adjust the tension.

Check：

Are the threads not being trimmed cleanly?

Adjustment：

Sharpen the fixed knives, or replace the fixed and moveable knives if necessary.

Check：

Is the needle too thick?

Adjustment：

Try using a needle with a count that is one lower than the current needle.

Check：

Is the length of thread trailing out from the bobbin case after thread trimming too short?

Adjustment：

If the bobbin is spinning loosely and idly, replace the anti-spin spring in the bobbin case.

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◎ Uneven seam.

Check：

Is the presser foot pressure too weak?

Adjustment：

Adjust the presser foot pressure.

Check：

Is the feed dog too low?

Adjustment：

Adjust the feed dog height.

Check：

Is the bobbin scratched?

Adjustment：

If the bobbin is damaged, smooth it with an oiled grindstone or replace it.

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◎ Large degree of puckering (excess tension)

Check：

Is the needle thread tension too strong?

Adjustment：

Make the needle thread tension as weak as possible.

Check：

Is the lower thread tension too strong?

Adjustment：

Make the lower thread tension as weak as possible.

Check：

Are the thread take-up spring tensions too strong?

Adjustment：

Make the thread take-up spring tension as weak as possible.

Check：

Is the thread take-up spring operating range too large?

Adjustment：

Lower the thread take-up spring as low as possible.

Check：

Is the presser foot pressure too strong?

Adjustment：

Adjust the presser foot pressure.

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Check：

Is the sewing speed too fast?

Adjustment：

Use the sewing speed control keys to gradually reduce the sewing speed.

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◎ Material slippage.

Check：

Is the presser foot pressure too strong?

Adjustment：

Adjust the presser foot pressure.

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◎ Lower thread is tangled at the sewing start. The bobbin does idle
　 running during thread trimming

Check：

Is the bobbin spinning direction correct when the lower thread is being pulled?

Adjustment：

Set the bobbin so that it turns in the opposite direction to the rotary hook.

Check：

Is there too much thread wound onto the bobbin?

Adjustment：

The bobbin winding amount should not be more than 80%.

Check：

Is the anti-spin spring attached?

Adjustment：

Attach the anti-spin spring.

Check：

Is the bobbin turning smoothly?

Adjustment：

If the bobbin is not turning smoothly, replace the bobbin.

Check：

Is a bobbin other that specified by SIRUBA being used?

Adjustment：

Use only bobbins which are specified by SIRUBA

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◎ Needle and lower threads are breaking.

Check：

Is the needle bent or is the needle tip broken?

Adjustment：

Replace the needle if it is bent or broken.

Check：

Is the needle correctlyinstalled?

Adjustment：

If it is incorrect, installed needle correctly.

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Check：

Is the machine properly threaded?

Adjustment：

If it is incorrect, thread the thread correctly.

Check：

Is the rotary hook sufficiently lubricated?

Adjustment：

(M1/H1/L2/M2 specifications)
If the oil gauge is down to the lower reference line in the oil gauge window, add more oil.

Check：

Is the upper or lower thread tension too weak or too strong?

Adjustment：

Adjust the needle thread or lower thread tension.

Check：

Is the needle thread may be loose because the thread take-up spring operating range is too small?

Adjustment：

Adjust the position of the thread take-up spring.

Check：

Is the rotary hook, feed dog or other part damaged?

Adjustment：

If they are damaged, smooth them with an oiled grindstone or replace the damaged parts.

Check：

Is the thread path damaged?

Adjustment：

If the thread path is damaged, smooth it with sandpaper or replace the damaged part.

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◎ Incorrect thread trimming (Upper and lower threads are both not
　 being trimmed)

Check：

Is the fixed knife or movable knife damaged or worn?

Adjustment：

Replace the fixed knife or the movable knife.

Check：

Is the needle properly installed?

Adjustment：

If it is incorrect, install the needle correctly.

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◎ Broken needle.

Check：

Is the material being pushed or pulled with excessive force during sewing?

Check：

Is the needle properly installed?

Adjustment：

If it is incorrect, install the needle correctly.

Check：

Is the needle bent, is the needle tip broken, or is the needle hole blocked?

Adjustment：

Change the needle.

Check：

It is extremely dangerous to leave any pieces of broken needle sticking in the material.

Adjustment：

If the needle breaks, search for all pieces until the whole of the needle is found.

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◎ Oil gauge (1) is not visible in oil gauge window.

Check：

Is the oil reservoir empty?

Adjustment：

(M1/H1/L2/M2 specifications)
Fill the oil tank with oil.

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◎ Machine does not operate when power is turned on and treadle
　 is pressed.

Check：

Is the power supply connector disconnected from the control box?

Adjustment：

Insert the connector securely.

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◎ Machine does not operate at high speed.

Check：

Is the sewing speed setting or backtack speed setting incorrect?

Adjustment：

Use the sewing speed control keys to set the high speed.

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◎ Machine stops during sewing.

Check：

Is the fixed stitch key turned on?

Adjustment：

Turn off the function of fixed stitch key.

Check：

Is the power supply voltage too low?

Adjustment：

Check the power supply. (If the power cord is too long or too many appliances are being run from a single outlet, this may cause voltage drops.)

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◎ Nothing appears on the operation panel display.

Check：

Is the power supply connector disconnected from the control box?

Adjustment：

Insert the connector securely.

Check：

Is the operation panel connector inside the control box disconnected?

Adjustment：

Insert the connector securely.

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