Melco EMC-6 Use and care manual

File: 16397 Rev. A Page 1 of 4
EMC6 Z-DRIVE ENCODER
REPLACEMENT PROCEDURE
P/N 16397 Rev. A
This procedure will step through removing and replacing the Hewlett-Packard encoder on the EMC6
(Black Head) Z-Drive with an equivalent U. S. Digital encoder. All the steps will either reference the
figure one assembly break out or the attached U.S. Digital encoder installation instructions.
Figure 1
Removal of Non-functioning Encoder:
1. Remove the top rear cover over the z-drive. At this point if the encoder will still take the machine
to head-up, a scribe mark or ink mark should be put across the black collar and bearing just in case
it is needed to set the head up function later.
2. Shut the machine off and disconnect the power to the machine.
3. Relieve the belt tension by backing off the two Item 10 screws enough for the motor bracket to
move up so the Item 5 pulley will come through the belt.
4. Remove the sheet metal plate Item 8, which allows access to the set screws that hold the pulley
(Item 5) to the Z-shaft. Loosen the two set screws and make sure the pulley is loose on the shaft.

File: 16397 Rev. A Page 2 of 4
5. Unplug the encoder from the CPU Board.
6. Remove the three Item 1 screws that hold the encoder mount plate (Item 4) in place.
7. You should now be able to remove the whole assembly of pulley, plate, and encoder. The encoder
internal disc is glued to the pulley shaft, so it will all have to come out together.
Installation of the New Encoder:
1. Install the new pulley on the shaft so it lines up with the motor pulley and tighten the two set
screws.
2. Put the belt back on the top pulley and tension it to specification by moving the motor bracket and
secure it once it is set.
3. Install the small cover, Item 8, back in its original position.
4. Install the encoder body onto the new encoder plate with the three tiny #0-80 screws.
5. Using the centering tool and the procedure included in the attached encoder installation
instructions, attach the plate back onto the standoffs with the Item 1,2,3 hardware. (See attachment
A)
6. Using the spacer on the install the encoder hub disk onto the shaft and only snug the set screws so
it will stay in this position.
7. Snap the encoder module into place and secure it with the two shorter 4-40 Pan Head Phillips
screws.
8. Plug the PCB into the encoder module and secure it to the Mounting plate with the two 6-32 Pan
Head Phillips screws with the two nylon spacers between the board and the mount plate.
9. Plug the cable into the new PC Board and then into the CPU Board where previous one was
plugged in.
Setting the Encoder Index to Machine Head-up
1. The best procedure to do this is to use a head up fixture that fits into the reciprocator and rests on
the top of the head. The fixture numbers are 994937-01 and 002920-01. To do this the Melco
network cable will need to be removed from the machine and then the power turned on.
IMPORTANT: This will prevent the RSA from downloading and causing the Z-Axis to run
away.
2. Remove the needle case and other parts so the fixture can be used on the reciprocator. Once it is in
place loosen the set screws on the encoder disk and rotate it until the green LED on the top corner
of the CPU Board turns on. Lock the set screws on the disk in place making sure that it is still
properly spaced and then remove the spacer that was put in #5 above.
3. Hold the encoder module so it doesn’t move and remove the two short 6-32 screws, snap the
encoder cover in place and install the two long 6-32 screws to hold it on.
4. This should complete the installation, and all the screws should be checked to insure they are tight.
5. Install the needle case and other associated parts back to their original position.
6. Power down the machine and plug the Melco Network cable back into the machine.
7. Power up and let the machine download.
8. Check for proper operation and if everything is ok put the rear cover back.
9. Happy Sewing!!!!!!!!!!!
Note: For other encoder setting options/procedures call the Remanufacturing/Depot Repair
Department at Melco Embroidery Systems, Inc.

File: 16397 Rev. A Page 3 of 4
Attachment A
1. Base Mounting
Secure base to mounting surface using two or three screws. If a centering tool is used, slip it over shaft
and into center hole of base. Tighten mounting screws, remove centering tool.
2. Spacer Installation
• For shafts less than 3/8", snap spacer tool clip around shaft. (Fig. A)
• For shafts equal to or larger than 3/8", place spacer tool next to shaft. (Fig. B)
Figure A Figure B
3. Hub/Disk Assembly Installation
Slip hub disk assembly over shaft with disk side down until it bottoms out against spacer tool. Tighten
set screw with hex wrench provided while pressing down on hub.

File: 16397 Rev. A Page 4 of 4
4. Encoder Module Installation
Slip optical module into position until two alignment pins slip into holes of module. Thick side side of
module should be out.
5. Cover Installation
Place housing (cover) over assembly and secure with two 4-40 x 5/8" cover screws (supplied).