Epson L1800 DTF Screeching Noise + Double-Error Lights After a Few Prints: Cap Station Alignment, APG Height, and Carriage Stop Adjustment

Customer Question

I watched your video about fixing a screeching DTF printer with double-error lights. I have an Epson L1800 with the same problem. I replaced the capping station and it works for a short time, but after about 4-5 prints the same screeching and double-error light issue comes back. How can I permanently fix it?

Answer

Why the problem returns after 4-5 prints even with a new capping station

When an Epson L1800 (and many L-series/1430/1390 style DTF builds) makes a screeching noise and then triggers double-error lights, it's often not that the cap station is "bad"-it's that something is misaligned, and the printhead is catching the cap assembly during parking/capping.

A brand-new capping station can temporarily "mask" the issue because the rubber seal is fresh and the springs are responsive, but if the geometry is off, the head will eventually catch again-especially as things warm up and shift slightly during repeated prints.

In other words: replacing the cap station helped, but the recurring failure strongly suggests an alignment/height/clearance issue, not a defective new part.

The most common root cause: APG height and capping clearance

The fix is to check and adjust the height of your APG, then confirm the parallelism and finally adjust the right frame stopper so the capping station won't catch the printhead.

These are the exact adjustments I recommend (in this order):

Step 1: Adjust APG height using the half-moon dial (right side)

On many L1800 frames, there's a half-moon dial on the right that changes the APG height. If the APG is too high (or uneven), the head can park too aggressively into the cap area, increasing the chance of catching or dragging.

What to do:

• Locate the half-moon dial on the right side of the carriage/APG mechanism.

• Adjust the height slightly and test.

• You're aiming for: solid sealing on the cap without the head "digging in" or scraping during the park motion.

Symptoms of APG too high:

• Head slams or drags at the far-right parking area

• Screeching happens right as it tries to cap

• The printer may stall, then flash the double error lights

Symptoms of APG too low:

• Poor cleaning performance

• Frequent nozzle dropouts because the cap doesn't seal well

• Ink drying issues / air ingestion

So you want the "sweet spot" where the head caps cleanly and quietly.

Step 2: Adjust the parallelism bar (left side)

Even if the overall APG height is close, the system can still be tilted-meaning one side is higher than the other. That tilt is often what causes intermittent catching after a few prints.

What to do:

• On the left side, adjust the parallelism bar so the head and cap interface are level across the width.

• If one side is higher, the head can rub or hook the cap edge, especially when the carriage returns fast.

Why this matters:
A slight tilt can "work" briefly, then fail once vibration/heat changes the mechanics during a run of prints.

Step 3: Move the right frame stopper about 1 mm to the right

Once APG height and parallelism are set, the final issue is often that the parking position is too tight. The carriage is stopping in a spot where the cap station can physically catch the head or the head carriage.

What to do:

• Identify the right frame stopper.

• Move it to the right by about 1 mm.

• This creates a tiny clearance buffer so the capping station won't catch the printhead during parking.

That 1 mm sounds small, but it's often the difference between:

• "Works for a few prints"
  and

• "Works consistently without random screech + double error lights"

Extra checks that help the fix stay permanent

Even after the three key adjustments above, these quick checks reduce repeat problems:

A) Confirm the cap station isn't shifted or skewed

If the cap station is not square to the head path, the head can catch one edge. Make sure mounting screws are snug and the assembly sits straight.

B) Watch for tube drag (DTF common)

DTF conversions add tubes, dampers, and routing that can pull the carriage slightly-especially near the parking area. If tubes tug when the carriage goes right, it can change the angle just enough to cause a catch.

C) Check for carriage rail friction

If the carriage doesn't glide smoothly, it can overshoot or slam slightly at the end position. Clean and lubricate appropriately (lightly and correctly-over-lubrication can create its own problems).

If you apply the adjustments in this order-APG height (half-moon dial on the right), then parallelism (bar on the left), and finally shift the right frame stopper ~1 mm to the right-that combination is the most reliable way to stop the recurring screeching and double-error light problem after a few prints.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. So, we're not able to provide remote troubleshooting, suggestions, or support for printer repairs. We do offer an in-person evaluation and repair service via our local diagnostic facility: Printer Repair Service (https://bchtechnologies.com/printer-repair-service). Given the high demand, we operate on a first-come, first-served basis, so it may take a few weeks before we can schedule your printer to be dropped off. Our services are structured to repair either a whole printer or specific parts, with clear instructions on how to proceed. However, we acknowledge that our rates aren't the most economical. Thus, we highly recommend that you resort to self-help via online research. You can start by checking out YouTube or visiting our YouTube channel's homepage BCH Technologies on YouTube (https://youtube.com/@bchtechnologies). Look for specific videos using the search icon next to "About" on the right-hand side of the menu bar. I receive dozens of queries every day asking about videos for specific topics. Having created videos over the past nine years, it's challenging to remember every single one. Therefore, using YouTube's search function would be most efficient. Plus, YouTube might suggest relevant videos from other channels that could assist you.

Thanks again for reaching out and for supporting the channel. I hope these adjustments help you get the L1800 running reliably-without the screeching return and without the double-error light shutdown after a few prints.