background image

f

 fig A-6

 fig A-7

g

 fig A-8

h

i

j

 fig A-9

- 3 -

6. Stand up the machine.

The terminal cover will come out.
Insert the screwdriver into the hole of machine from
backside.
Hook the tip of driver into the groove of forward-
reverse adjusting 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 push the left bottom
corner (h) of front cover upward. The hook inside of the
cover will come off. (fig. A-8)

9. Bring up the front cover carefully.

Disconnect the two cord connectors (i, j) from the CPU
curcuit board. (fig. A-9)

Terminal
cover

Summary of Contents for PRO BL8800

Page 1: ...MODEL BL8800 SERVICE MANUAL...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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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