Epson ET-2760 Error 100077 After Mainboard Replacement: Scanner Lamp and Motor Troubleshooting

Question

I installed a new mainboard from BCH Technologies in my Epson EcoTank ET-2760. As soon as I powered the printer back on, it displayed error code 100077. I checked the scanner cables, and they appear to be connected correctly, clean, and undamaged. Nothing seems to be blocking the scanner carriage from moving, but turning the printer off and back on does not clear the error. What should I check next?

Answer

The E-02 / 100077 error is generally associated with the scanner unit failing its startup initialization. When the printer powers on, the scanner assembly should perform a brief self-test. The scanner lamp should illuminate, and the scanner carriage should move from its resting position, travel a short distance, and return to its home position. If the printer does not detect the expected lamp or carriage response, it can stop the startup sequence and display error 100077.

Since the error appeared immediately after replacing the mainboard, begin by observing exactly what the scanner does during startup.

Check Whether the Scanner Lamp Illuminates

Turn the printer off, wait approximately 30 seconds, and then turn it back on while watching through the scanner glass.

The scanner lamp should light briefly during initialization. Depending on the scanner design, the light may appear white or slightly bluish. You may need to view it from an angle or perform the test in a dimmer room to see it clearly.

If the scanner lamp does not illuminate at all, possible causes include:

• A disconnected or incorrectly seated scanner ribbon cable

• A damaged scanner cable or connector

• Contamination on the cable contacts

• A failed scanner lamp or scanner sensor assembly

• A damaged connector or scanner-control circuit on the replacement mainboard

• A mainboard that is incompatible with the exact ET-2760 hardware revision

If the scanner lamp remains completely dark even after the cables have been reseated, the scanner lamp or scanner image-sensor assembly may have failed. The lamp is normally integrated into the scanner carriage rather than replaced as a simple standalone bulb, so the practical repair may require replacing the scanner carriage assembly or the complete scanner unit.

Before concluding that the lamp is defective, unplug the printer and carefully inspect the scanner cable again. Ribbon cables can look connected while still being slightly crooked or not inserted deeply enough. Make sure the cable is fully inserted, perfectly straight, and locked into the connector. Also inspect the cable contacts for scratches, ink contamination, oxidation, folds, or torn conductive traces.

Check Whether the Scanner Carriage Moves

If the lamp illuminates, watch and listen for scanner movement.

The scanner carriage should normally move during startup. You may hear a short motor sound, followed by the carriage traveling across a small portion of the scanner bed. If the lamp turns on but the carriage remains stationary, the scanner motor or its drive system may not be operating.

Possible causes include:

• A disconnected scanner motor cable

• A failed scanner motor

• A jammed scanner carriage

• A damaged scanner drive belt

• A loose, stretched, or detached belt

• A broken scanner gear or pulley

• A damaged scanner motor driver circuit on the mainboard

• A cable connected to the wrong socket or inserted in the wrong orientation

With the printer unplugged, inspect the scanner mechanism for anything that could prevent the carriage from moving. Even if the scanner bed looks clear from above, the carriage may be mechanically jammed underneath the glass. A displaced belt, broken plastic guide, foreign object, or dried lubricant can stop the carriage from completing initialization.

Do not force the scanner carriage aggressively. Applying too much pressure can damage the belt, motor, carriage guide, or scanner sensor. If the carriage can be accessed safely, it should move with controlled resistance rather than feeling completely locked.

If the scanner lamp turns on but there is no motor sound or movement, the scanner motor circuit becomes the primary area to investigate. Check the scanner motor cable at both ends, if accessible. A cable may have been loosened while the printer was opened for the mainboard replacement.

Inspect All Scanner Connections Again

The timing of the failure is important. Because error 100077 appeared immediately after installing the new board, the problem may be related to a connection rather than a scanner component that happened to fail at the same moment.

Unplug the printer from the wall before touching any internal cables. Then check the following:

1. Confirm that every scanner-related ribbon cable is connected to the correct mainboard socket.

2. Make sure each ribbon cable is facing the correct direction.

3. Verify that the connector locking tabs are fully closed.

4. Look for bent contacts, cracked sockets, or partially lifted connector locks.

5. Check whether any ribbon cable was pinched beneath a cover or screw.

6. Compare the new board with the original board to confirm that all connectors and component numbers match.

7. Inspect nearby cables that may control the scanner motor, lamp, or home-position sensor.

Ribbon cables are especially sensitive. If a cable is inserted at a slight angle, some electrical contacts may connect while others do not. This can allow the printer to power on normally but prevent the scanner from initializing.

If you still have the original mainboard and it was able to power the scanner before the replacement, reinstalling it temporarily may help isolate the problem. If the scanner operates with the original board but shows 100077 with the replacement board, the issue may involve board compatibility, a defective replacement board, or a connection that changes when the replacement board is installed. If the same error occurs with both boards, the scanner assembly, motor, cable, or sensor is more likely to be responsible.

Check the Scanner Home-Position Sensor

The scanner carriage must detect its home position during startup. If the carriage moves but cannot identify the starting position, the printer may continue attempting to initialize and then display error 100077.

Possible home-position problems include:

• A dirty scanner calibration strip

• A blocked or defective home-position sensor

• A carriage that cannot travel fully to its home position

• A loose scanner belt

• A damaged scanner carriage flag or sensor tab

• Contamination inside the scanner assembly

If the carriage moves repeatedly, makes a grinding sound, or travels in the wrong direction before the error appears, the home-position sensing system should be examined. Do not continue cycling the printer repeatedly if the carriage is grinding, because this can damage the scanner belt or gears.

Confirm Mainboard Compatibility

The Epson ET-2760 may have different production revisions, regional versions, or board firmware configurations. A replacement board can appear physically identical while still having a different firmware, connector layout, or hardware revision.

Compare the identification numbers printed on the original board and replacement board. Minor differences do not always indicate incompatibility, but a substantially different board number or regional designation can be significant.

If the scanner worked before the board replacement and all cables are confirmed to be installed correctly, provide BCH Technologies with the original board number, replacement board number, printer serial information, and clear photographs of the board connections. This information can help determine whether the replacement board is the correct revision for the printer.

Most Likely Diagnosis Based on What the Scanner Does

The scanner's behavior during startup provides the most useful clue:

• The scanner lamp does not illuminate: Suspect the scanner lamp or image-sensor assembly, scanner ribbon cable, connector, power circuit, or an incompatible or defective mainboard.

• The lamp illuminates, but the carriage does not move: Suspect the scanner motor, motor cable, drive belt, gear system, mechanical obstruction, or motor-control circuit.

• The lamp illuminates and the carriage moves but cannot complete initialization: Suspect the home-position sensor, calibration strip, carriage obstruction, loose belt, or incorrect scanner feedback to the mainboard.

• Nothing happens in the scanner area: Recheck all scanner power, signal, and motor connections, and verify that the replacement board matches the printer.

• The scanner worked before the board replacement: Give special attention to cable seating, connector damage, board compatibility, and the possibility of a defective replacement board.

The related BCH Technologies video, Solved! The Secret to Fixing Error E-02 100077 for Epson WF-2830 and WF-2850 [https://www.youtube.com/watch?v=_YWAtMXJbcU], discusses the same general scanner initialization error. Although the printer models differ, the central diagnostic principle remains useful: determine whether the scanner lamp illuminates and whether the scanner carriage moves.

Addressing printer issues can be complicated because many faults require direct observation, disassembly, electrical testing, and hands-on inspection. For that reason, we are unable to provide individualized remote troubleshooting, repair instructions, or ongoing repair support. We do offer in-person evaluation and repair through our local printer diagnostic and repair facility [https://bchtechnologies.com/printer-repair-service]. Due to high demand, services are handled on a first-come, first-served basis, and it may take several weeks before an appointment or printer drop-off becomes available. Our service options cover either a complete printer or certain removable components, with instructions provided on the service page. We also recognize that professional repair may not be the most economical option for every printer, so we strongly encourage self-guided research when appropriate. You can begin with YouTube or visit the BCH Technologies YouTube channel [https://youtube.com/@bchtechnologies]. On our channel page, use the search icon near the "About" section to search for your printer model, error code, or specific component. We receive dozens of questions each day requesting particular videos, and after producing repair content for more than nine years, it is difficult to remember every video by title. YouTube's search feature is therefore the fastest way to locate relevant material, and it may also recommend helpful videos from other repair channels.

Thank you again for contacting BCH Technologies and for taking the time to explain what happened after the mainboard installation. We sincerely appreciate your support and hope these observations help you determine whether error 100077 is being caused by the scanner lamp, scanner motor, cable connections, home-position system, or mainboard compatibility.