This procedure is SPECIFIC TO THE PFAFF 7570. It MAY work for you. Try at your own risk.
Small flat screw driver.
Large Phillips screw driver
Small torx screw driver
Large torx screw driver
Small cleaning brush
Small scissors and long tweezers.
Old tooth brush.
Lots of care and patience.
In this particular case, perseverance was the winner. I'm quite handy with mechanical things, so I had to partially disassemble the machine until I found the cause of the problem. The foot presser mechanism DOES have a spring, but it's concealed and out of sight. I never suspected it, but that was the case. When I found it, white grease that was put there at the factory to lubricate its movement had turned into a think sticky gunk. That was what was holding the foot presser in the up position. This gunk was so stubborn! I had to clean the spring, the housing and a plastic pin really well, and then oiled all the components inside their housing. More below.
The shaft of the foot presser is hollow at the top. This is designed to hold a 1-5/8" spring and a 5/8" black plastic pin that's inserted at the top of the spring and protrudes from the hollow shaft.
Start placing the 7570 on a table that has a height that's comfortable for you. You'll be standing and squatting a lot to accomplish the task.
Standing behind the machine, and looking down, there's a metallic plate on your right that holds the thread tension discs. This plate covers the shaft, found underneath, and holds together the mechanism with the round wheel with numbers that protrudes slightly on the side of the machine's body.
Several pieces had to be disassembled in order to get to this plate, although at this point I'm doubting whether or not so much work was necessary, since I was so excited upon the discovery that I forgot to notice whether I could have found the spring and remove it without having to disassemble so many pieces.
The metal plate is black and thick, and is held down with a heavy gauge black machine screw. The plastic pin makes contact with the underside of this plate, which compresses the spring when the foot presser lever is up. Once the lever is disengaged from its locked or resting position (in the case of the embroidery position), the compressed spring pushes the entire foot presser down, as it DID when I first bought the machine.
These are the disassembly steps, without diagrams, but use your imagination as best you can to picture my description.
1 - Top cover removal.
The top cover (the one with the different built-in patterns drawn on its inside face) is held in place by two thin black metal plates where it hinges. A little bit of pressure towards the outside on the top of one of the plates (on either side) will release the pivot pin on one end, and then a little jiggle in the same direction will release the other. Put the cover aside.
2 - Concave top cover removal.
This cover is the one that houses the thread spool in the horizontal position, if that is your choice when sewing. It is held down by two plated machine screws, one short and one long. After removing the screws a little jiggling will help removing it, pulling it mainly upwards. You may need to put the large handle up, to allow for more movement. Put it aside once removed.
3 - Side cover removal.
This covers the area where the foot presser is housed, on the left side of the machine, as you face the buttons on the front of the machine.
Standing behind the machine, once step 2 has been achieved, one can see from the top, looking down, a large black machine screw on your right hand side, just inside the cover. You don't need to remove it completely, just about 1/2 turn will loosen the pressure to release the cover. Pull the cover outwards and sideways and set aside. You may want to also remove the light bulb, to be able to get to the mechanism to clean it, to remove pieces of thread that may be lying around or caught in the different moving parts. Push the light bulb gently in while turning it counter clockwise. You'll feel it disengaging from its socket. Pull it out and set it aside. Clean it if necessary. Use the scissors and the tweezers to remove any lint and debris.
4 - Pressure discs plate removal.
I'm not 100% sure now that this can be done at this stage, but continue. If this particular plate cannot be removed, because other components get in the way, then skip to step #4A below and come back here later.
Standing behind the machine, looking down at the housing, you'll see another large black machine screw holding down a black metal plate. Remove it completely and put it aside. Next, remove the plate, gently nudging its way out of the different obstacles that may be present. One of them may be the sewing shaft mechanism. If this is the case, gently turn the wheel manually to cause the mechanism to move up or down, as to allow more room for the plate to be completely removed.
Make sure you lift this plate slowly, as to prevent the spring and plastic pin from spilling inside the machine's body. Put the plate aside. Now you see the black plastic pin, perhaps stuck inside the hollow part of the foot presser. If so, pry it loose gently and clean it with a sudsy solution, and use an old tooth brush to remove the gunk from its coils. Do likewise to the plastic pin.
While you have the housing exposed with lots of space, I would suggest you should remove any debris, dust, etc, and oil all the moving parts with sewing machine oil.
5 - Assembly.
This is done in the reverse order. Congratulations! You've done it!
Additional steps, if metal plate in step 4 above cannot be removed after step 3.
4A - Front plate removal (The one with the colored buttons and LCD display).
Standing behind the machine, looking down, you'll see a grey ribbon cable crossing the case from back to front, under the main shaft. Remove its connector by pulling it up gently. No force or tools are necessary. Bend the ribbon to one side and set it aside, out of the way.
Squatting a little from the same position, looking inside the foot presser housing, you'll see two small plated screws, close to the edge of the housing, one towards the top and another towards the bottom. Remove completely.
In the same squatting position, and moving your attention to the main machine housing, you'll see the green PCB board. It's held by at least three screws. One of them, on your extreme left, is not visible because it's concealed by a plastic insert at the top of the left end of the 7570. This insert is held down in place by a thin black metal plate. This plate has a tiny hole where the top cover of step 1 hinges.
Gently turn the small torx screw holding down this plate 1/2 turn counter clockwise to release the pressure. Once loosened, slide the plate slightly towards your right. This will allow you to pull the insert up.
With the insert out of the way, squatting again, you'll see the third plated screw on your left. Remove it.
Turn the machine upside down and ensure it's not rocking from side to side.
Use the large torx driver to remove the machine's base. This base contains a power supply box, and another green PCB board. It's connected to the rest of the machine with several ribbon cables of different colors. The base is attached by 4 machine screws. Loosen the screws completely and remove using the tweezers.
Raise the base from the right end, allowing its other end to rest on the edge of the inverted 7570 body and stand it at 90°. Inspect the location, orientation, and general layout of the cabling. You may need to unlatch one or more plastic holders for the ribbons, which hold them flat and organized. Remove these holders to have greater access to the connectors.
Jot down the order of the different ribbons and the way the are inserted into their sockets on the PCB found inside the base. Fortunately the connectors are of different sizes, and there should be no way to insert the wrong one in the wrong socket, but it's best to be safe. Jot down order, color, etc.
Gently pull on the different connectors from the PCB board. A little bit of force is all that is needed. Push them aside one by one in order to allow you to see more and create more space.
Next, disconnect the large power cord. You need to insert a small flat screw driver to release pressure on the sides of the socket. Do it one side at a time, and then gently pull it out. Set the base aside. You're almost done!
Next, looking down, pushing the ribbon cables away from you, you'll see two plated screws in each corner of the inverted 7570 housing, on the side closest to you. Remove completely. At this time you should be able to remove the face plate, gently threading the widest of the ribbon cables through the opening on your left, in order to put the base aside.
With the face plate out of its position, put the machine in its straight up position and step 4 above can be accomplished.
Now, I also did remove the 7570 main handle in order to create more space and see more in the reduced area of the foot presser housing. If you too find it necessary to do so, use the corner of the tip of a small flat screw driver to pry the lock ring open, being careful not to allow it to spring out of your fingers and falling inside the case. Slide the pin out and then the handle itself, horizontally.
Go back to step 4 above if you came here because you could not do step 4.
on Jun 02, 2020