Here's a video showing how to replace the top panel. It shows the large model but the 128 is identical except for the length. If you're replacing the white playing surface, simply install the new surface instead of replacing the existing one.

When replacing the white playing surface and top panel, note that the white playing surface is intentionally made slightly small, so you must stretch it slightly while attaching the screws. This stretching will help prevent the playing surface from becoming loose if hot weather causes the silicone material to expand. Also, note that the screws press together the electrical contacts of the internal touch sensor and circuit board. So if a screw is too loose, the sensor won't make contact and Y-axis may not work on the nearly columns. Or if too tight, the silicone rubber will bulge out and not look pretty. The panel screws can be tightened within a very wide range and still work fine. Here's how to correctly stretch the playing surface and to correctly tighten the screws: 

1) align the white playing surface centered on the sensor and circuit board below it.
2) Replace the top panel, aligning the 8 left-side control buttons in the 8 holes of the panel.
3) Insert 2 screws above and below the left column of pads and tighten them using this giuideline:

Tighten the screw until its head is level with the top panel and you start to feel the increased resistance of the screw being fully seated in the hole. Then tighten an additional 1/4 turn only and no more.

4) Now stretch the right side of the playing surface slightly such that there is a 1mm margin between the edges of the pads and the inside edge of the top panel. 1mm is half the distance that is between any 2 pads. While holding the playing surface stretched, tighten the 2 screws above and below the right column using the above tightening rule.
5) Insert the screws along the rear edge, stretching the rear edge of the playing surface so that there is a 1mm border between the upper edge of the pads and the inside edge of the top panel, then tighten the screws using the above rule.
6) Insert the screws along the front edge, stretching the front edge of the playing surface so that there is a 1mm border between the lower edge of the pads and the inside edge of the top panel, then tighten the screws using the above rule.
7) Insert the 2 left-side and 2 right-side screws, tightening only enough that the screw head is level with the top panel and no more.
8) To insure that the screws are tightened correctly, test Y-axis response on one pad within each column by moving your finger forward and backward while watching a MIDI monitoring app to check for CC74 (default) output, or any other way to verify that Y-axis is working. If one column isn't sending Y-axis, tighten the screw above or below that column by 1/4 turn to fix it.

If you live in hot weather and your replacement touch sensor sheet arrived warm, give it some time to cool down.

Here's a video showing how to disassemble and reassemble your LinnStrument. It shows the large model but the 128 is identical except for the length. Follow the video to:

1) Remove the top panel screws and top panel,
2) Peel off the white playing surface,
3) Carefully remove the black Touch Sensor Sheet from the circuit board,
4) Fast-forward to position 7:00 and carefully insert the new Touch Sensor Sheet,
5) Replace the white playing surface,

Next you will replace the top panel. Note that the white playing surface is intentionally made slightly small, so you must stretch it slightly while attaching the screws. This stretching will help prevent the playing surface from becoming loose if hot weather causes the silicone material to expand. Also, note that the screws press together the electrical contacts of the internal touch sensor and circuit board. So if a screw is too loose, the sensor won't make contact and Y-axis may not work on the nearly columns. Or if too tight, the silicone rubber will bulge out and not look pretty. The panel screws can be tightened within a very wide range and still work fine. Here's how to correctly stretch the playing surface and to correctly tighten the screws: 

6) align the white playing surface centered on the sensor and circuit board below it.
7) Replace the top panel, aligning the 8 left-side control buttons in the 8 holes of the panel.
8) Insert 2 screws above and below the left column of pads and tighten them using this giuideline:

Tighten the screw until its head is level with the top panel and you start to feel the increased resistance of the screw being fully seated in the hole. Then tighten an additional 1/4 turn only and no more.

9) Now stretch the right side of the playing surface slightly such that there is a 1mm margin between the edges of the pads and the inside edge of the top panel. 1mm is half the distance that is between any 2 pads. While holding the playing surface stretched, tighten the 2 screws above and below the right column using the above tightening rule.
10) Insert the screws along the rear edge, stretching the rear edge of the playing surface so that there is a 1mm border between the upper edge of the pads and the inside edge of the top panel, then tighten the screws using the above rule.
11) Insert the screws along the front edge, stretching the front edge of the playing surface so that there is a 1mm border between the lower edge of the pads and the inside edge of the top panel, then tighten the screws using the above rule.
12) Insert the 2 left-side and 2 right-side screws, tightening only enough that the screw head is level with the top panel and no more.
13) To insure that the screws are tightened correctly, test Y-axis response on one pad within each column by moving your finger forward and backward while watching a MIDI monitoring app to check for CC74 (default) output, or any other way to verify that Y-axis is working. If one column isn't sending Y-axis, tighten the screw above or below that column by 1/4 turn to fix it.

While stretching the playing surface sheet, tighten the screw until its head is level with the top panel and you start to feel the increased resistance of the screw being fully seated in the hole. Then tighten an additional 1/4 turn only and no more.

Finally, perform a Touch Sensor Calibration, as described on the Panel Settings page, Global Settings tab, "Actions" section, "Calibrate" subsection. This will teach the internal computer the exact boundaries of each of the pads.

Note that replacing your Main (larger) circuit board will reset all of your settings to new factory defaults.

‍Here's a video showing how to disassemble and reassemble your LinnStrument. It shows the large model but the 128 is identical except for the length. Follow the video to:

1) Remove the top panel screws and top panel,
2) Peel off the white playing surface,
3) Remove the circuit board assembly from the chassis, being careful not to apply any force to the black Touch Sensor Sheet,
4) On the back of the circuit board assembly, remove the 6 (4 on LinnStrument 128) hex nuts and ribbon connector, then separate the 2 circuit boards,
5) Replace the faulty circuit board (larger Main board or smaller LED board) with the new circuit board, then reattach the boards together with the same hex nuts and ribbon cable,
6) Reinsert the circuit board assembly back into the chassis,
7) Replace the white playing surface,

Next you will replace the top panel. Note that the white playing surface is intentionally made slightly small, so you must stretch it slightly while attaching the screws. This stretching will help prevent the playing surface from becoming loose if hot weather causes the silicone material to expand. Also, note that the screws press together the electrical contacts of the internal touch sensor and circuit board. So if a screw is too loose, the sensor won't make contact and Y-axis may not work on the nearly columns. Or if too tight, the silicone rubber will bulge out and not look pretty. The panel screws can be tightened within a very wide range and still work fine. Here's how to correctly stretch the playing surface and to correctly tighten the screws: 

8) align the white playing surface centered on the sensor and circuit board below it.
9) Replace the top panel, aligning the 8 left-side control buttons in the 8 holes of the panel.
10) Insert 2 screws above and below the left column of pads and tighten them using this giuideline:

Tighten the screw until its head is level with the top panel and you start to feel the increased resistance of the screw being fully seated in the hole. Then tighten an additional 1/4 turn only and no more.

11) Now stretch the right side of the playing surface slightly such that there is a 1mm margin between the edges of the pads and the inside edge of the top panel. 1mm is half the distance that is between any 2 pads. While holding the playing surface stretched, tighten the 2 screws above and below the right column using the above tightening rule.
12) Insert the screws along the rear edge, stretching the rear edge of the playing surface so that there is a 1mm border between the upper edge of the pads and the inside edge of the top panel, then tighten the screws using the above rule.
13) Insert the screws along the front edge, stretching the front edge of the playing surface so that there is a 1mm border between the lower edge of the pads and the inside edge of the top panel, then tighten the screws using the above rule.
14) Insert the 2 left-side and 2 right-side screws, tightening only enough that the screw head is level with the top panel and no more.
15) To insure that the screws are tightened correctly, test Y-axis response on one pad within each column by moving your finger forward and backward while watching a MIDI monitoring app to check for CC74 (default) output, or any other way to verify that Y-axis is working. If one column isn't sending Y-axis, tighten the screw above or below that column by 1/4 turn to fix it.

If you replaced the larger Main (larger) circuit board, you must perform a Touch Sensor Calibration, as described on the Panel Settings page, Global Settings tab, Actions section, "Calibrate" subsection.

If you replaced the Main (larger) circuit board on a LinnStrument 128, please change the value of the Touch Sensor Prescale setting to 90. To learn how to do this, open the Panel Settings page, Global Settings tab, and search for "prescale".