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To identify the type of machine, the serial number will start with 136_ _ _ _ for a black sewing head and 903_ _ _ _ for a grey sewing head.

THE MACHINE WON'T COME ON. THE DISPLAY IS BLANK:

1. Check power cable to see if it is plugged in to the rear of unit and insure it is plugged into the wall socket.
2. Check that the wall socket has power.
3. Black Sewing Head: If the fan in the rear of the machine is not turning, (Do not remove fan cover.) turn off the machine and remove the left side (Melco Logo) and turn the machine back on. Are there any lights illuminating. Disconnect the power harness inside the unit. The harness in a Black Head is located in the cabinet behind the black painted metal grill near the bottom. Remove the two screws securing the assembly and gently slide the assembly out. There will be three connectors (small, medium and large). Disconnect the large one first and slide the assembly back in and turn power on. Observe the fan. If there is power to the fan then there is a problem in the circuit board area or possibly in the power supply strip. Disconnect the next connector and repeat process. If the fan never come back on replace the power supply. Refer to the Illustrated Parts Manual and find part number. Call your local distributor to order the part.
4. If there are lights from the above procedure. Remove the theta PCB (Second smallest PCB, three red lights) using grounding precautions (refer to Grounding Precautions and PCB Removal). With PCB removed turn unit on. Is the fan turning or the lights on? The Theta PCB is probably bad. Refer to the Illustrated Parts Manual and find part number. Call your local distributor to order the part.
5. Gray Head: To disconnect the power harness one must remove the keyboard cover (Refer to tech. man.). Then look towards the front of the power supply, the bottom, and locate the clear or white colored connector with a bunch of wires going to it. If you are looking at wires on a round cylinder closest to the Y drive belt your are in the wrong area. Go more to the right side if standing in front of unit. Turn on the switch and observe the fan. If it does not move then replace the fuse(s). To do this disconnect the power cable. Then take a small screw driver and find the notch above where the power cable would normally go into and pop out the plastic piece. Replace the fuse(s). Check with a local hardware or Radio Shack. If the fuses blow again, then the power supply needs to be replaced.
6. If the fan starts to work, after replacing the fuse(s). Reconnect the harness and remove the 4 axis PCB (procedure is in the tech. manual). Turn unit on and see if the lights work. If not, then either the PCB is bad or there is another load to the power supply. Disconnect all the connectors in the head housing area (theta motor area). Write down which way the wires are positioned and located. Turn unit on and observe the lights on the left side. If the lights come on, then reconnect the wires one at a time to determine the cause of the lights to go out. This will help narrow the source of the problem down.

BURN SMELL OR SMOKE:

1. Turn off the unit! Remove power cord in the rear. If you are reading this and just now turned off the unit and it was doing either, more than likely it is to late. Write down where the smoke or odor was coming from. Take a piece of tape and place it near the area. Refer to the following:
2. Remove Melco logo cover and observe PCB(s). Look for any burn marks or damaged components. Remove PCB(s) one at a time and replace. Refer. tech. Manual for PCB removal. If a damaged PCB is found refer. to the Illustrated Parts Manual to find the part number order the part from your local distributor.
3. Next remove the keyboard cover to the right of the sewing head. Look for cable discoloration or shorted wires. Look at the connectors. Disconnect them and reconnect with the power off. If a damaged cable is found keep unit off and disconnected and call your local distributor for service.

THETA TIME OUT ERROR:

1. Turn unit off and check for any mechanical bind in the theta area (red knob in front of head) or Z drive (rear motor belt) by turning the mechanical parts. If a bind is present then remove the needle plate and check for birds nesting or broken needle tips.
2. Next, remove the PCB cover and turn unit on. Are all of the lights on? If not turn unit off and remove the theta PCB, then turn unit on again. Did the error go away?. Remove the X/Y amp next. Turn unit on. Did the error go away? If not turn unit off, put cards back in. If no bind is present, Then replace the theta PCB and install the most current RSA files.

PRESSER FOOT NOT UP:

1. Check wire connections on the switch. The switches are located above and below the presser foot handle. Each switch has two wires connected to it. With a flat head screw driver, push and hold the contact of the switch, does the unit continue to power up? Does touching the sensor contact several times cause the machine to make a clicking noise? Try both switches. See if the handle is touching the little contact point on the switch. If not adjust the switch up/down by loosening its screws. If it cannot be adjusted any further then adjust the handle height.

THREAD IS NOT PICKING UP:

1. More than likely the thread has not been pulled through the outer hole and the looper hole (referred to as the snake eye). Check the needle to see if the tip is intact, or in the proper position (nine o'clock), needle depth, thread tension, or looper position are proper. Rethread the looper hole, replace the needle, adjust tensions, and then adjust the looper position so half of the looper hole is exposed.

POOR SEWING QUALITY:

1. If the moss is looking poor, verify the design structure. Do other designs sew fine? Check needle plate hole for proper size, free of burrs, proper looper settings, nipple is not cracked, looper setting, thread tension, thread path, and theta belt. Is the needle loose inside the needle bar rod? If so remove needle, clean thread area and use red loctite to secure it. Let it set for over an hour for proper querying. Look at the presser foot and see if it is centered around the nipple. Check the presser foot height, nipple height from the needle plate hole, needle height position, and the needle type. Check the needle type: Long hook, Short hook, or no hook. Long hook is designed to sew better on chain stitch designs, Short hook is a universal needle and can sew both moss and chain effectively, no hook is well suited for moss applications.

SOMETIMES IT IS NECESSARY TO ADJUST THE TENSIONS SO LOOSE THAT THE KNOBS ARE ABOUT TO FALL OFF:

1. Chenille tension is generally loose. This often depends on what type of thread is being used. If it has a lot of fibers, this will create more resistance in the thread path. Select different style of needle, or different type of thread and adjust the tension(s) correctly.

THREAD BREAKS:

1. Check the needle plate for any burrs on the inner ring and the needle plate hole for any burrs or scaring. Check thread path for any sharp points of contact. Take a piece of thread and run it over any surface that the thread makes contact with. If any surface causes the thread to fray, replace the defective part.
2. Insure the proper hole is selected for the proper needle. Check that the proper nipple size is being used.
3. Adjust proper needle height. Replace the needle plate, needle, and possibly the nipple if needed.
4. Check and adjust the Looper timing if needed.
5. Try a different thread. Possibly the cone being used is old and brittle.
6. Observe that the presser foot is touching the fabric as it is sewing. If it is not touching, then lower the presser foot so it will touch the fabric while sewing. If the presser foot is too low then it will reduce the sewing quality. Sometimes with the presser foot too low, it will get stuck in the moss and cause a needle break. If the presser foot cannot be adjusted any higher, remove the presser foot and the barrel and gently tap the presser foot shaft back into the barrel.

Z TIME OUT ERROR:

1. Make sure there is no thread build up under the needle plate.
2. Lubricate the oiling and greasing points throughout the machine.
3. Clean the looper area.
4. Check for a mechanical bind, by turning the Z motor belt in the read, with the unit off. Feel the Z motor to see if it is warm indicating a bind. Replace any part causing a bind.
5. Check cabling and connections.
6. Turn the machine off and back on and reconfigure the unit.
7. Go to head timing menu and cycle to head up by pressing the Alt-Up arrow key at the same time.
8. If all of the above fail to fix the problem, replace the CPU PCB.

POWER UP MESSAGE:

1. If the display remains on "power up" and the computer is on and in the EDS program, the RSA files disk may need to be re-installed. To install the software refer to the proper EDS Operation Manuals. A test to see if it can possibly be the RSA files, is to configure the unit as an EMC6. If the machine goes beyond the power up mode and into the normal display mode, the RSA files disk needs to be installed.
2. Remove the cover on the left side and turn on the unit. Look to make sure that all of the lights are on. If the light on the front green circuit board is out. Turn the machine off and disconnect the harness that goes to the theta motor and the actuator. Turn the unit back on and see if it powers up normal into the CH-1 mode. If it does then reconnect one of the plugs and try it again. If it the light goes back out then a theta PCB and or the CPU may need to be replaced.
3. This applies only to the black headed CH-1 units. Check all voltage levels and see if the 24DC volts are present on the theta PCB. This PCB is the mid sized one and is located towards the front of the unit. There are three test points labeled TP-1(+24 DC Volts) TP-2(+5 DC Volts), and TP-3(Ground). If the voltage on TP-1 and TP-3 reads 0 DC Volts or is very low then the power supply needs to be replaced.

FAN IS NOT TURNING/MAKING NOISE:

1. (Black Sewing Head) To verify if the fan is not turning place your hand near the fan outlet to feel the air. If there is none, turn unit off and remove the filter. Turn unit back on and observe the fan. If it turns then the fan filter needs to be cleaned or replaced.
2. If there is still no fan, check the keyboard display to see if there is power to the unit. If there is still no power, remove the power cord from the rear of the unit. Next remove the two screws located behind the main tensioning knob assembly on the black metal grill. Gently slide out the power supply assembly. DO NOT pull on the wires. Verify that unit is off. Disconnect one of the connectors, plug in the power cord and turn the machine on. Is the fan working? Repeat the above steps for the other connectors. DO NOT keep hands near the power supply when turning unit on. If the fan come back on, something else in the machine is loading the power supply down. If the fan does not come back on, disconnect the power supply harness in the rear of the unit and slide the whole power supply out when all of the connectors are removed. Locate the fan and insure the wires are intact. To test the fan, unplug the connector and place a new 9 volt battery across the leads of the fan. Bridging wires will be needed for this process. If the fan turns, then the power supply is probably bad. Refer to the Illustrated Parts Manual and order the proper part form your local distributor.
3. (Gray Sewing Head) If the fan in the rear of the machine is not blowing air out, make sure there is information on the keyboard display. If not, disconnect the power harness under the keyboard cover and turn unit back on. If there is no airflow, replace the fuses inside the black socket where the power chord plugs into the power supply. Use a screw driver and pop out the tab where he power cord fits into. If replacing the fuses doe not work, replace the power supply. Refer to the Illustrated Parts Manual and locate the part. Call your local distributor to order the part.
4. (Black/Gray Sewing Head side fan cover) The side cover fan is not blowing. Place your hand to feel the air being circulated into the head. If nothing can be felt, turn off the unit and remove plate. Be sure not to remove the cover completely. The fan harness has a limited amount of wire reach. Observe the connector and the wires. If the wire is damaged, have it repaired. For the gray sewing head, if the wires are intact, replace the 4-axis PCB.

THETA NOISE:

1. If there is a groaning noise after the needle has been brought up, adjust the belt tension on the theta motor a little tighter. Do not place too much tension on the belt or it may break. If the problem gets worse, then loosen up on the belt tension. If it remains the same, then possibly the belt needs to be replaced. Look at the inner side of the belt. Rotate the pulley manually with the unit off and check the teeth. Look for a mechanical bind in the theta movement with the unit off by rotating the needle assembly (George) in a clockwise direction.

THREAD IS NOT BEING PICKED UP:

1. Check the needle height position and the angle of the needle.
2. Check the looper position. It can be seen by looking through the outer hole in line with the needle path. The hole should be 1/4 to 1/2 exposed toward the front of the unit. If the whole is fully exposed it may need to be adjusted.
3. The tension may be too tight. Loosen up both pretension and main tension.
4. Select another needle height much higher.

THETA POSITION IS OFF:

1. If powering up the unit the needle bar drive assembly does not line up consistently do the following. Turn off the unit and remove the left side cover with the Melco Logo on it. Raise the red collar (Located in the front needle case) up by loosening it's screws. Insure it does not touch the metal bracket of the needle case housing. Next loosen the single screw in the gear below the red knob and raise it up. Line up the locking plate (Tongue) manually. Turn the unit on and let it power up. Make sure the needle drive assembly (George) is squared. Observe the red light on the smaller board on the theta PCB. All three lights should be on. Loosen and bring the gear back down and mesh it into the receiving gear (leave a little clearance to the gears). Tighten down the screws and turn off the unit and wait a minute and turn it back on. The unit should power up normal. If not repeat the process.

LOCKING PLATE IS STICKING OUT:

1. If the locking plate (Tongue) is sticking out after the needle has been brought up, remove the needle bar holder and take off the two Philip head screws that secure the top plate. Observe the springs to see if they are damaged or are missing the pins that fit inside. Replace the pins or springs if they are damaged. Refer to theta position off section for adjustments if needed. Go to the section on Theta Position is off and go through its steps.

THETA KEEPS TURNING:

1. If after turning on the machine the theta keeps spinning in cycles, turn the machine off and check the wire(s)/connectors inside the sewing head that hook up to the small PCB. Remove the side fan cover so the theta motor is exposed. Next remove the small PCB (be careful not to lose any of the washers or disconnect any wires). Next turn theta manually until the narrow slit is visible. Take a piece of paper and run it through the opening. Sometimes oil can get inside there and clog the signal that needs to pass through. Next look at the small circuit board for any burn marks or damaged components. Clean the black "U" shaped sensor with a piece of cloth. Avoid using any chemicals in cleaning the sensor. If cleaning does not provide the solution, then replace the encoder PCB, replace the Theta PCB, and/or reconfigure the machine.

NEEDLE BREAKS:

1. Check the needle plate. Make sure it is centered and that the proper needle hole has been selected.
2. Try other various materials or needle types.
3. Check the needle height.
4. Look under the needle plate for any thread gathering or piling up.
5. Replace the nipple with a new one and of the proper size.

NO X/Y MOVEMENT:

1. Turn off the power and remove the left side cover
2. Observe the bank of red lights (that are off) on the rear large PCB.
3. Move the carriage back and forth moderately and left and right Do two lights flicker or glow? If they do then the wiring and the motor appear to be fine. One should check the 24 volts coming from the power supply. Replace the X/Y amp PCB. Part number is located on the printed circuit board.

NO X MOVEMENT:

1. Repeat the procedure as above.
2. If it randomly does not work. Replace the flex cable.
3. If the Led(s) come on one way but not the other then replace the X/Y PCB. This is the little circuit board located on the big board.

NO Y MOVEMENT:

1. Repeat the procedure for No X/Y Movement.
2. Check the encoder connector located at the rear of the motor. Push it in lightly.
3. Move the pulley on the motor shaft in and out and see if it is loose.
4. If the Led(s) come on one way but not the other then replace the X/Y PCB. This is the little circuit board located on the big board.

X RACK NOT DONE:

1. If the error is getting progressively worse, replace the flex cable located on the left had side of the unit (Black sewing heads only).
2. Turn unit off. Make sure that the wires going to the motor from the circuit board are properly connected (Left side cover needs to be removed).
3. Check the wiring going behind the brass plate of the motor mount bracket to see if any of the several wires are crossing over one another.
4. Replace the X/Y Circuit Board located under the left rear cover, on the bigger circuit board.

X BEAM ERRATIC MOVEMENT:

1. Do the steps in No X/Y and No X or Y Movements.
2. Determine where and in which direction the beam was sewing before the erratic behavior. Look at the sew pattern to determine which way it was sewing. Turn unit off and check wiring that is related to the movement. For example; if it was sewing left to right , then check all of the X motor wiring. If, it is in the Y movement then check Y motor wiring.
3. If in the X then replacement of the flex cable or motor maybe needed.

POOR SEWING QUALITY IN THE X DIRECTION:

1. Look at the belt itself. Located under the X beam. Observe the belt teeth which are located on the inside of the belt. Move the carriage from left to right. Are teeth missing? If so, replacement of the belt is needed. Procedures for replacing the belt can also be obtained.
2. Tighten the X belt pulley a little. The screw is located on the side of the right side of the beam . Turn the Allen screw a quarter at a time and no more than one and a half revolutions at the most. Note! Tightening the belt to much it already tight or over tightening will cause damage to parts on the sewing unit.

POOR SEWING QUALITY IN THE Y DIRECTION:

1. Remove the two most outer side covers and look at both long belts. Move the beam to the rear and pinch the belt in the middle on both sides. Do they both have the same tensions? If not adjust the screw on the front pulley and move the beam from front to back a few times to distribute the tension. Check the tension one more time.
2. Remove the right rear cover where the keyboard is located. Check the pulley and the belt also. Do not adjust it, unless it is obvious that it needs it. If adjusting is required, then only in small incremental turns. If the tension is to tight one can damage other parts of the unit.

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