Epson 1390 Error 0x55 After Carriage Replacement: Diagnosing a UNINET DTF 1000 That Will Not Home

Question

My UNINET DTF 1000, which uses an Epson 1390 J-series printing mechanism, developed a bad carriage sensor. After replacing the carriage and reassembling the printer, the carriage will no longer return to its home position. The printer displays flashing white and blue lights, and WICReset reports fatal error 0x55, described as an "out of paper" error.

I have already checked the carriage belt and the encoder strip, but the problem remains. What else could cause error 0x55 and prevent the carriage from homing?

Answer

What Epson Error 0x55 Usually Indicates

On an Epson 1390-based printer, error 0x55 is generally associated with the paper-feed, or PF, drive system. Although WICReset may describe it as "out of paper," this does not necessarily mean that the printer is simply waiting for paper.

In this context, the error can indicate that the printer commanded the PF motor or paper-feed mechanism to move but did not receive the expected encoder feedback. It may also occur when the paper-feed mechanism is physically overloaded, mechanically locked, disconnected, or unable to rotate the expected distance.

Possible causes include:

• A disconnected PF motor cable

• A disconnected or damaged PF encoder FFC

• A PF encoder scale that is outside the sensor slot

• A dirty or damaged PF encoder sensor

• A jammed paper-feed roller or gear

• An incorrectly installed PF timing belt

• A mechanically overloaded paper-feed system

• A damaged PF motor

• A defective motor-driver circuit on the mainboard

The Epson 1390 service documentation identifies the PF motor, PF encoder sensor, PF encoder FFC, PF scale, timing belt, gears, and mainboard connections as important parts of the paper-feed feedback system. (studylib.net)

However, because this problem began immediately after replacing the carriage, the reported error may be the result of a cable, sensor, or mechanical component that was disturbed during the carriage replacement. The carriage and paper-feed systems are checked together during the printer's startup sequence, so a reassembly problem in either system can stop the sequence and produce a fatal error.

Retrieve the Printer's Stored Error With the Epson Adjustment Program

The first step is to confirm the most recent internal error using the Epson Adjustment Program for the Epson 1390 platform. WICReset is helpful for reading counters and certain status information, but its error descriptions can be abbreviated or generic.

To retrieve the stored error:

1. Connect the printer directly to the computer with a USB cable.

2. Open the Epson 1390 Adjustment Program.

3. Select the printer model and the USB port showing the printer's name.

4. Select Particular Adjustment Mode.

5. Scroll down and select Printer Information Check.

6. Click Check.

7. Review the error history displayed by the program.

The newest stored error should appear at the top as Error No. 1. Record the complete number exactly as displayed. A longer internal error code may provide more specific information than the shorter 0x55 message shown by WICReset.

A video demonstrating this diagnostic process is available here:

Epson Adjustment Program error-checking video [https://youtube.com/shorts/FPZzpyYuZLE]

You can then search for "BCH Epson Error" or visit our Epson Triple Secret Error Codes reference [https://bchtechnologies.com/blogs/blog/epsons-triple-secret-error-codes] to look for the longer code and its component-specific meaning. BCH's Adjustment Program guidance also explains that the newest stored error appears as Error No. 1 under Printer Information Check. (BCH Technologies)

The Adjustment Program is normally intended for technicians and printer servicing. Some DTF printer manufacturers provide the correct version for the Epson mechanism used in their equipment. It is best to request it from the printer supplier or obtain it from a trusted source, because unknown download sites may distribute incorrect or unsafe files.

Recheck the Carriage Encoder Strip and Encoder Sensor

Since the carriage was replaced, the carriage encoder system should be inspected again even if the strip itself appears undamaged.

The clear encoder strip must pass directly through the narrow slot in the carriage encoder sensor. It is possible for the strip to appear correctly positioned from the front while actually running behind, above, or beside the sensor slot.

Check the following:

• The encoder strip passes through the center of the encoder sensor.

• The strip is not twisted.

• The strip is not installed backward.

• Both ends are correctly attached and under proper tension.

• The strip is not rubbing against the carriage frame.

• There are no fingerprints, grease, ink, or cleaning solution on the strip.

• The encoder sensor is firmly attached to the replacement carriage.

• The encoder sensor board is not cracked or tilted.

• The sensor FFC is fully inserted into the encoder board.

• The other end of the sensor FFC is fully inserted into the mainboard.

The Epson 1390 service documentation specifically notes that a carriage that moves incorrectly or strikes the printer frame can be caused by the carriage encoder strip not passing through the sensor, a dirty strip, a contaminated encoder sensor, a damaged sensor board, or a disconnected sensor FFC. (studylib.net)

Clean the encoder strip only with a soft, lint-free material and minimal pressure. Avoid pulling the strip sideways or using strong solvents, because the position markings can be damaged.

Inspect the Sensor FFC From the Replacement Carriage

The sensor FFC deserves particular attention because it may have been disconnected, folded, pinched, or partially inserted during the carriage replacement.

On the Epson 1390 mechanism, the sensor FFC connects the carriage encoder sensor board to the mainboard. If this cable is disconnected or damaged, the printer cannot reliably determine where the carriage is located.

Inspect it for:

• A connector that is not fully seated

• A cable inserted at an angle

• Exposed contacts that are not completely inside the socket

• A reversed contact orientation

• Sharp folds or creases

• Torn cable edges

• Cracked conductive traces

• Ink or cleaning-fluid contamination

• Damage where the cable passes through a retaining guide

• Pinching between the carriage assembly and printer frame

Disconnect the printer from power before touching any FFC cable. Do not insert or remove an FFC while the printer is powered. A crooked or contaminated cable can create an electrical short and damage the sensor, printhead, or mainboard.

Check the Relay FFC and Carriage-Motor Connections

Replacing the carriage often requires removing covers and moving cables near the relay board. A loose relay FFC can create a fatal startup error even when the carriage belt and encoder strip are installed correctly.

Inspect the relay FFC between the relay board and mainboard. On the Epson 1390 platform, this connection is associated with relay-board connector CN1 and mainboard connector CN5. Also inspect the carriage-motor circuit and the connection associated with mainboard connector CN6.

A connector can look installed while being slightly offset or not fully locked. Remove power, release the connector carefully, inspect the cable contacts, and reinstall the cable straight and evenly.

The Epson service manual lists a disconnected relay FFC, a damaged relay FFC, a disconnected CR motor cable, and a damaged carriage-motor connection among the possible causes of a fatal error during startup. (studylib.net)

Confirm That the Carriage Can Move Freely

With the printer turned off and unplugged, check whether the carriage can move smoothly across the entire carriage shaft. Do not force it while the carriage lock or capping station is engaged.

Look for the following conditions:

• The carriage belt is installed on both pulleys.

• The belt teeth are properly engaged with the motor pulley.

• The belt is not twisted.

• The belt tensioner and spring are correctly installed.

• The replacement carriage sits correctly on the carriage shaft.

• The carriage bushings are not binding.

• No FFC cable, ink tube, or circulation tube is pulling against the carriage.

• No tube or wire is trapped beneath the carriage.

• The carriage does not contact the printer frame.

• The carriage can enter and leave the capping station without obstruction.

A DTF conversion introduces additional ink tubes, dampers, circulation lines, or cable chains that are not present in the original Epson configuration. After carriage replacement, one of these added components may be too short, routed incorrectly, or caught behind the carriage.

The carriage should move with consistent resistance. A tight spot in one area can indicate a bent shaft, misaligned carriage bushing, incorrectly installed carriage, or obstruction.

Do not apply random household oil to the carriage shaft. Excessive or unsuitable lubricant can contaminate the encoder strip and attract dust. Epson's service documentation calls for a specified lubricant on the carriage shaft when servicing the carriage drive. (studylib.net)

Inspect the Capping Station and Carriage Lock

A carriage that appears unable to home may actually be blocked by the capping station or carriage-lock mechanism.

Check whether:

• The carriage lock releases during startup.

• The capping platform can move vertically.

• The wiper is not jammed against the printhead.

• Dried ink is not preventing the capping station from moving.

• The pump gears rotate without binding.

• The carriage can enter the home position without striking the cap.

• The waste-ink tubes are not interfering with the pump mechanism.

If the capping station is assembled out of phase or the carriage lock remains raised, the carriage motor may attempt to move the carriage but detect excessive resistance. The printer may then stop the initialization sequence and display a fatal error.

Inspect the APG Motor and Sensors

The Epson 1390 uses an APG, or automatic platen-gap, mechanism to change the printhead-to-paper spacing. This mechanism is involved in the startup sequence and can also prevent successful initialization.

Check:

• The APG motor connector associated with mainboard connector CN9

• Both APG sensor connections

• The APG sensor cables

• The APG gears and timing marks

• The carriage-shaft height mechanism

• Whether the APG assembly was reinstalled in the correct mechanical phase

If the APG assembly was moved during the carriage replacement, its gears may no longer be synchronized. The printer can interpret an incorrect APG position as a fatal startup condition. The Epson service documentation lists the APG motor, APG sensors, their connectors, and the relay-board connections among the components to inspect when a fatal error occurs during power-on. (studylib.net)

Check the PF Motor Connection

For error 0x55, inspect the PF motor cable even if the repair was performed mainly around the carriage.

The PF motor connects to mainboard connector CN7 on the original Epson 1390 mechanism. Verify that:

• The connector is fully inserted into CN7.

• The wires have not pulled out of the connector housing.

• The cable is not trapped beneath a cover or frame.

• The PF motor turns smoothly.

• The motor pinion is engaged with the PF timing belt.

• The timing belt is not loose, twisted, or off its pulley.

The Epson service manual identifies a disconnected PF motor cable, damaged motor wiring, or failed PF motor as possible causes when the PF motor does not operate during startup. (studylib.net)

Inspect the PF Encoder Sensor, FFC, and Scale

The PF motor uses rotary encoder feedback to determine how far the paper-feed rollers have moved. A PF encoder problem can produce a feed-related error even when there is no paper jam.

Inspect the PF encoder area for:

• A PF encoder scale or disc that is outside the sensor slot

• A loose PF encoder sensor holder

• A disconnected PF encoder FFC

• A damaged or creased encoder FFC

• Ink mist, dust, or grease on the scale

• Dust inside the optical sensor

• A cracked encoder disc or scale

• A damaged sensor board

• A missing screw or mounting tab

On this platform, the PF encoder FFC connects through the PF encoder sensor board and relay-board connector CN6. Be careful not to confuse this CN6 reference on the relay board with the carriage-motor connection designation on the mainboard.

A useful observation is the PF roller's behavior during startup. If the PF roller suddenly rotates very fast for approximately half a turn before the error occurs, the printer may not be receiving valid PF encoder feedback. Epson's troubleshooting documentation directs technicians to check the PF encoder holder, PF encoder FFC, sensor contamination, and whether the PF scale passes correctly through the sensor slot. (studylib.net)

Examine the Paper-Feed Mechanism for Mechanical Resistance

Turn the paper-feed mechanism carefully by hand with the printer unplugged. It should rotate without a hard stop, grinding noise, or unusually heavy resistance.

Inspect:

• The PF timing belt

• PF motor pinion gear

• PF roller gears

• Paper-eject roller gears

• ASF loading mechanism

• DTF film-feed modifications

• Added tension rollers

• Foreign objects in the paper path

• Loose screws or cable ties

• Hardened ink deposits

• Misaligned brackets

• A film sensor or guide pressing against a roller

Because the UNINET DTF 1000 is a converted system, it may contain film-handling components that differ from the original Epson 1390. A film-feed modification, external roller, or added sensor can overload the original PF mechanism or prevent the encoder from detecting expected movement.

Observe Exactly What Happens at Startup

The printer's movement before the lights begin flashing can help identify the affected system.

If the carriage does not move at all:
Check the CR motor, CR motor cable, relay cable, relay FFC, carriage lock, and mechanical binding.

If the carriage moves slightly and stops:
Check for a tight carriage, incorrectly routed tube, carriage lock interference, capping-station obstruction, APG positioning problem, or belt issue.

If the carriage moves in the wrong direction or strikes the frame:
Check the carriage encoder strip, encoder sensor, sensor FFC, and sensor-board connection.

If the carriage moves normally but the paper-feed rollers do not move:
Check the PF motor, CN7 connection, PF belt, gears, and mainboard motor-driver circuit.

If the PF roller turns rapidly and then stops:
Check the PF encoder scale, PF encoder sensor, sensor holder, and PF encoder FFC.

If the error begins when the carriage reaches the home position:
Check the capping station, carriage lock, pump mechanism, APG mechanism, and physical alignment of the replacement carriage.

These observations are usually more useful than the flashing-light pattern by itself, particularly on a converted DTF printer whose external controls may not match the original Epson control-panel design.

Disconnect Power Before Rechecking Connections

Turn the printer off and disconnect it from electrical power before checking internal cables or moving assemblies. Leave it unplugged for several minutes before touching the mainboard or FFC connections.

Do not repeatedly power the printer when a motor is stalled or the carriage is striking the frame. Repeated startup attempts can:

• Damage the carriage belt

• Overheat a motor

• Damage a motor-driver circuit

• Tear an FFC cable

• Break a gear

• Damage the replacement carriage

• Cause the printhead cables to short

After checking the mechanical movement and all disturbed connectors, reconnect the printer and perform one controlled startup while observing the sequence.

The Mainboard Should Be Considered After the Mechanical and Sensor Checks

A failed PF motor driver, carriage motor driver, damaged fuse, or other mainboard problem can produce a fatal error. However, because the printer worked before the carriage replacement, an assembly, connection, routing, sensor, or mechanical problem is statistically more likely than a mainboard failure unless power was applied with a cable reversed, offset, contaminated, or shorted.

Before replacing the mainboard, verify:

• All FFC cables are installed in the correct connectors.

• No FFC is shifted sideways by one contact.

• No connector contains ink or cleaning fluid.

• The carriage and PF mechanisms move freely.

• The CR and PF encoder systems are correctly assembled.

• The APG mechanism is properly phased.

• No motor cable was confused with another connector.

• The replacement carriage sensor is compatible and functional.

Addressing printer problems can be complicated because many diagnoses and repairs require direct, hands-on inspection. For that reason, we are unable to provide individualized remote troubleshooting, repair suggestions, or continuing technical support for printer repairs. We do offer in-person evaluation and repair through our local printer diagnostic and repair facility [https://bchtechnologies.com/printer-repair-service].

Because demand for this service is high, printers and repair components are accepted on a first-come, first-served basis. It may take several weeks before an appointment or drop-off opportunity becomes available. Our repair services are structured to address either a complete printer or certain removable components, with instructions explaining how to submit the appropriate item.

We also recognize that professional repair may not be the most economical solution for every printer. Therefore, we strongly encourage independent online research as a practical starting point. You can search YouTube generally or visit the BCH Technologies YouTube channel [https://youtube.com/@bchtechnologies].

On our channel homepage, use the search icon located near the "About" section on the right side of the menu bar. Search phrases such as Epson 1390 fatal error, Epson 1390 0x55, 1390 carriage encoder, 1390 PF encoder, 1390 twin lights flashing, or Epson Adjustment Program error check may help locate relevant videos.

We receive dozens of inquiries every day asking us to identify a particular video for a specific printer problem. After creating printer-repair content for more than nine years, it is difficult to remember every individual video. Using the channel's search function is usually the fastest and most efficient method. YouTube may also recommend useful videos from other channels that address the same mechanism or error.

Thank you again for contacting BCH Technologies and for providing the details about what happened before error 0x55 appeared. We sincerely appreciate your engagement and support, and we hope this information helps you identify the connection, sensor, or mechanical component preventing the Epson 1390 carriage from completing its home-position sequence.