Procolored L1800 Not Printing Yellow After Installing a Grade B Printhead

Question:

I recently purchased and installed a Grade B printhead for my Procolored L1800 printer. I understand that printheads do not come with a warranty. I also spent many hours working with Procolored tech support while installing the printhead, new ink lines, new dampers, and a new printer cable. Even after going through troubleshooting with them, the printer still will not print yellow. What else can I check to get the yellow channel working?

Answer:

Since your Procolored L1800 is not printing yellow after a Grade B printhead installation, I would approach the issue as an ink-delivery and suction problem first, before assuming the yellow channel on the printhead itself is bad. A missing yellow channel can be caused by the printhead, but it can also be caused by an empty damper, poor damper seating, an air leak, a bad capping station seal, a clogged capping station, or a weak/blocked waste ink line.

The first thing to confirm is that the yellow damper has enough ink inside it. Since you already worked with Procolored tech support and replaced the ink lines and dampers, they probably checked this, but it is still worth verifying. The yellow damper should not be mostly air. If the damper is empty, half-empty, or full of bubbles, the printhead may not be receiving enough yellow ink even though the cartridge or tank has ink. Also make sure the yellow ink line is not kinked, pinched, blocked, or connected to the wrong channel.

Next, check whether the capping station is working correctly. On an Epson L1800-based DTF printer, the capping station is extremely important because it seals against the bottom of the printhead and allows the pump to pull ink through the nozzles during cleaning. If the capping station does not seal well, the printer may go through cleaning cycles without actually pulling ink through the yellow nozzles. This can make it look like the printhead is defective when the real issue is poor suction.

One basic way to check the capping station is to look for waste ink movement during a cleaning cycle. When you run a normal cleaning, you should see waste ink coming out through the waste ink line. If no waste ink comes out, or if the waste line only moves a tiny amount of ink, the pump, cap top, tubing, or seal may not be working properly.

Another useful test is a "park and prime" procedure. This helps you determine whether the printhead is sealing correctly on the capping station and whether ink can be pulled through the nozzles.

To do a park and prime, turn the printer on and allow the printhead to move and settle naturally on the capping station. It is safe to let the printer park itself with the power on. Once the printhead is parked, connect a syringe and tube to the printer's waste ink line. Hold the syringe upward and gently begin drawing from the waste line.

Start by gently drawing about 4 to 6 ml. At this point, you should feel slight, steady resistance. That resistance is important. If you pull only air with almost no resistance, then the printhead may not be parked correctly, the cap top may not be sealing against the printhead, or there may be an air leak in the capping station or waste ink tubing. If you feel complete resistance and cannot draw anything at all, the capping station or waste line may be clogged. In that case, the printhead cannot be properly primed until the blockage is cleared.

If the seal is good and the nozzles are open, you may hear or feel the damper membrane crinkle slightly as you draw. This usually means the suction is reaching the ink system. Continue pulling slowly until the syringe reaches the 10 ml mark. Because the syringe is held upward, the air and ink will separate. Ideally, after drawing to 10 ml, you may see ink rise to around the 6 ml mark, meaning you pulled roughly 4 ml of ink. Hold it for about 10 seconds before releasing.

Because DTF ink is thicker than regular dye ink, it often needs extra help to get started after a printhead, damper, or ink-line replacement. However, you should be gentle. Pulling too aggressively can introduce more air, damage dampers, or stress the printhead. The goal is to create steady suction, not forceful suction.

After the park and prime, run the printer's regular cleaning routine. Avoid strong cleaning within the next 12 hours if possible, and do not run back-to-back cleanings repeatedly without giving the printer time to rest. Too many cleaning cycles in a row can overheat or stress the printhead and may also flood the capping station.

If yellow still does not print after confirming the damper has ink and the capping station can pull ink properly, then the next areas to check are the yellow channel connection and the printhead electronics. Since you already replaced the printer cable, inspect the printhead cable seating again carefully. Make sure the cable is fully inserted, straight, clean, and not reversed. Also inspect the printhead connector for ink contamination, corrosion, bent pins, or damage. Even a small amount of ink on the cable contacts can affect one or more channels.

You should also confirm whether the printer is failing only on yellow, or whether yellow is partially firing. A nozzle check can tell you a lot. If the yellow section is completely blank, that usually points to one of three possibilities: no ink reaching the yellow nozzles, no suction through the yellow nozzles, or no electrical firing on that channel. If yellow appears broken, faint, or intermittent, that more often suggests air, clogging, weak ink flow, or partial nozzle blockage.

Because this is a Grade B printhead, there is also the possibility that the yellow channel was weak, clogged, or electrically damaged before installation. Grade B parts can be usable, but they are not the same as new printheads and may already have imperfections. That said, I would not assume the printhead is bad until you confirm that the yellow damper is filled, the cap top seals correctly, the waste line pulls ink with steady resistance, and the cable/connector area is clean and properly seated.

We have a video that may help with getting a printhead working after installation or ink-flow interruption: How to Get Your Printhead Working [https://youtu.be/CEXLEj6L6jw]. It may be especially useful for understanding the priming process and how the capping station helps pull ink through the printhead.

Addressing printer issues can be complicated because many of these problems require hands-on inspection. For that reason, we are not able to provide remote troubleshooting, suggestions, or repair support for individual printer repairs. We do offer an in-person evaluation and repair service through our local diagnostic facility, which you can find here: BCH Technologies Printer Repair Service [https://bchtechnologies.com/printer-repair-service]. Due to high demand, we operate on a first-come, first-served basis, so it may take a few weeks before you can drop off your printer. Our services are structured to repair either a complete printer or specific parts, with clear instructions on how to proceed. However, we understand that our rates may not be the most economical option for everyone. For that reason, we strongly recommend self-help through online research whenever possible. You can start with YouTube or visit our YouTube channel homepage at BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. Use the search icon next to the "About" tab on the right side of the menu bar to search for specific topics. I receive dozens of questions every day asking about videos for very specific printer problems, and after creating videos for the past nine years, it is difficult to remember every single one. YouTube's search function is usually the fastest way to find the most relevant video, and it may also recommend helpful videos from other channels.

Thank you again for reaching out and for supporting BCH Technologies. I hope these steps help you narrow down whether the missing yellow is caused by ink supply, capping station suction, cable connection, or the printhead itself.