background image

 b

0

0

1

1

 B

 F

 W

0

1

0

1

 O

0

1

- 15 -

b. Condition of switches and

sensors

The condition of each switch and sensor is indicated as
follows.

BH f: Buttonhole lever switch -Front

1=Neutral

0=Lever is pushed.

BH b: Buttonhole lever switch -Back

1=Neutral

0=Lever is pulled.

Lower the buttonhole lever and check these switches by
pushing or pulling this lever.
Also, using this mode, you can adjust the buttonhole lever
position. See next page “b-1 Adjustments for buttonhole
lever position”.

S: Stop sensor

1=not intercepted

0=intercepted

T: Timing sensor

1=not intercepted

0=intercepted

s: Speed sensor

1=not intercepted

0=intercepted

These sensors are intercepted by the slit plates on the
main shaft.
Stop sensor = Stop slit, Timing sensor = Timing slit,
Speed sensor = Speed slit
Turn the handwheel and check the response of each
sensor.

B: Sensor of needle bar position
1=not intercepted

0=intercepted (left needle position)

This sensor is intercepted by the lever of gear on the
zigzag pulse motor shaft.
Move the needle bar right or left and check the response
of this sensor.

F: Feed sensor
1=not intercepted

0=intercepted (feed dog is coming

most frontward)
This sensor is intercepted by the lever of gear on the feed
pulse motor shaft.
Remove the base and turn this pulley to check the
response of this sensor.

W: Bobbin winder switch
1=Bobbin winder spindle is in right position
0=Spindle is left position
Move the bobbin winder spindle left or right and check
this switch.

O: Presser foot switch
1=Presser foot is lowered, 0=Presser foot is lifted

Lower or lift the presser foot lifter and check the response
of this switch.

Buttonhole lever switch -Front

Buttonhole lever switch -Back

Stop sensor

Timing sensor

Speed sensor

Sensor of needle bar position

Feed sensor

Bobbin winder switch

Presser foot switch

Stop slit

Timing slit

Speed slit

Sensor

Main shaft

Sensor

Gear

Sensor

Gear

Содержание PRO BL8800

Страница 1: ...MODEL BL8800 SERVICE MANUAL...

Страница 2: ...11 11 ZIGZAG TIMING NEEDLE STOP POSITION 12 12 MOTOR BELT TENSION 12 13 TIMING BELT TENSION 12 14 BACKLASH OF HOOK GEAR 13 15 UPPER THREAD TENSION UNIT 13 16 ADJUSTING THE LOWER THREAD TENSION 13 LOCA...

Страница 3: ...e light cover fig A 1 2 Remove the left side screw b inside the thread take up lever cover fig A 2 3 Remove the screw c located on the backside of machine above the spool pin fig A 3 4 Tilt the machin...

Страница 4: ...knob f fig A 6 Slide them to the left and remove the knob 7 Hook the tip of screwdriver to the front cover holder g and pull down fig A 7 8 Tilt the machine backward again Hold the machine casting and...

Страница 5: ...ension guide n fig B 2 3 4 Check that the tension releasing mechanism has been connected certainly 4 Press the left side of front cover downward so that the hook inside of cover will snap into a place...

Страница 6: ...cing between the surface of hook race and the top edge of needle eye must be 5 2 0 2 mm fig 1 2 Turn the handwheel until the top edge of needle eye is aligned with the surface of hook race at this tim...

Страница 7: ...d you until the needle will cross over the hook fig 2 1 Then check the gap between needle and hook is about 0 02 to 0 1 mm fig 2 2 If the needle is hitting against the hook or if the gap is too much a...

Страница 8: ...t side of needle fig 3 1 At this time the gap between the tip of hook and the top edge of needle eye should be 1 5 to 2 0 mm If the gap is too small or too large adjust as follows 5 Tilt the machine b...

Страница 9: ...of the feed dog correctly by turning the inner screw b fig 4 2 4 Hold the screw b and re tighten the lock nut a 5 Re check the height and motion of feed dog by turning the handwheel 5 NEEDLE PLATE AND...

Страница 10: ...l the guide lines on the lower shaft and feed cam are aligned 4 Tighten the screws a Next check the timing of the up down movements 5 Turn the handwheel toward you until the needle comes to its lowest...

Страница 11: ...the screw d fig 7 3 If the forward stitch is finer than the reverse stitch turn the screw to the right fig 7 2 b If the reverse stitch is finer than the forward stitch turn the screw to the left fig...

Страница 12: ...er foot lifter has a slight play in down position 10 HEIGHT OF NEEDLE THREADER If the height of needle threader is not correct the hook on therader will not enter the needle eye Adjsut as follows 1 Re...

Страница 13: ...N If the motor belt tension is too tight or too loose machine will not run smoothly Adjust as follows 1 Remove the front cover 2 Loosen the screw a fig 12 3 Push the pulley towards the belt so that th...

Страница 14: ...ou have adjusted the backlash of hook gear check the timing of the hook again sec 3 15 UPPER THREAD TENSION UNIT The upper thread tension regulator unit has been adjusted to the best sewing conditions...

Страница 15: ...ch fig I 3 When this program has started correctly the LCD will indicate the machine icon and version number of this program fig I When buttons are released the LCD will change to indicate the Frequen...

Страница 16: ...dle bar position 1 not intercepted 0 intercepted left needle position This sensor is intercepted by the lever of gear on the zigzag pulse motor shaft Move the needle bar right or left and check the re...

Страница 17: ...ile lifting the presser foot lifter slightly Then slowly move frame back again Lower the lifter when BH f changes to 0 5 At this time the presser foot frame should be about 1 mm forward from the extre...

Страница 18: ...f foot controller and speed control lever The condition of foot controller is indicated on the first line of LCD Foot controller is not connected the number 255 will appear Connect the foot controller...

Страница 19: ...ser foot is lifted Check the Presser foot switch by Self diagnostic program Exchange the Presser foot switch Exchange the CPU circuit board Bobbin wind icon is appeared although the Bobbin winder spin...

Страница 20: ...rcuit board LCD does not indicate Exchange the LCD board Exchange the CPU circuit board Can not control sewing speed by Speed control lever Check the condition of the Speed control lever by Self diagn...

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