Epson ET-8550 Only Printing Cyan After Replacing a Fried FFC Cable: Ink Delivery Checks Before Assuming a Shorted XP600 Printhead

Question

I'm looking for some expertise with an Epson ET-8550. The printer's FFC cable was accidentally damaged ("fried"), so we ordered a replacement cable and installed it. Now the printer will only print cyan-none of the other colors show up. We've run multiple nozzle cleanings and test prints, but nothing changes.

How likely is it that the XP600 printhead is short-circuited? Are there any other tips we should try?

Answer

You're asking the right question-"Did the printhead short?"-but the fact that cyan prints is a very important clue. In most ET-8550 cases after an FFC cable failure/replacement, the printhead is not electrically "dead", and the root cause is more often ink delivery, air intrusion, or poor suction/capping, not burned data lines.

1) How likely is a short-circuited XP600 printhead if cyan still prints?

The signal lines on the XP600 printhead (data, clock, and logic control) operate at very low current, so they are unlikely to burn or fail electrically in the way power lines do. Also, because cyan is printing, it strongly suggests the printhead is still receiving commands and responding-meaning the communication side is functioning.

A true electrical failure severe enough to kill multiple channels often shows up as:

• the printer not firing any ink at all,

• obvious driver/board faults, or

• repeated, consistent failures that aren't affected by ink delivery improvements.

So, while printhead damage is possible, it's not the first conclusion I'd draw when one channel is still firing.

2) Why "only cyan prints" often points to ink delivery, not electronics

After an FFC cable incident and replacement, it's extremely common for the ink system to be disturbed. Any of the following can cause multiple channels to stop printing even if the head electronics are fine:

• Air in the dampers/lines
  Air is the #1 enemy after a disturbance. A channel with air can fail to prime and will simply "not show," even with repeated cleanings.

• Dampers not fully primed (or partially collapsed)
  The printhead relies on stable ink feed. If dampers aren't properly filled/primed, several colors can starve while one (cyan) happens to recover first.

• Cap station not sealing properly
  Cleanings depend on suction through the cap. If the cap doesn't seal tightly against the printhead, the pump can't pull ink through the dead channels, and cleanings become ineffective or even introduce more air.

• Weak/blocked waste pump path
  If the pump can't move fluid properly, you'll see "no improvement" no matter how many cleans you run.

• Over-cleaning making things worse
  Repeated strong cleanings can overwork the system, increase air intrusion, and saturate the cap/wiper area. It can also overfill the waste path and create inconsistent suction.

3) What to focus on before assuming printhead damage

Before you treat this as a shorted head, your best diagnostic approach is to confirm the printer can reliably pull ink through all channels.

A. Prime ink delivery properly (remove trapped air)

• Make sure each channel has a solid ink column with minimal bubbles.

• If your setup allows it, carefully prime each damper so it's filled and stable (not half-air).

• If you see bubbles returning quickly after a cleaning, that often means the system is pulling air due to a leak, poor seal, or weak suction.

B. Verify the cap station seal and suction
A good cap seal is what makes cleanings work. Things to look for:

• cap rubber condition (swollen, torn, hardened, deformed),

• cap height/alignment,

• ink pooling patterns that suggest the head isn't sealing evenly,

• signs the pump is pulling (movement of fluid into the waste line during cleaning).

If the cap isn't sealing, cleanings may mostly pull air-not ink-from the inactive channels.

C. Use gentle recovery instead of repeated strong cleanings
If you've already done many cleanings with no change, doing more often:

• overheats/over-stresses the system,

• introduces more air, and

• wastes a lot of ink.

At that point, the smarter move is to step back and correct ink delivery fundamentals (prime + seal + suction).

4) When partial printhead damage becomes more likely

If you confirm all of the following:

• dampers are properly primed with stable ink,

• the cap station seals well,

• suction/pump is actually moving fluid, and

• ink can be drawn through the channels reliably,

...but only cyan still prints and every other channel remains completely absent over multiple controlled tests, then partial printhead damage becomes more plausible.

That said, even in that scenario, it's worth re-checking the basics one more time because "only one color prints" is still very commonly delivery-related-especially right after an FFC incident.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems, and that's why we're not able to provide remote troubleshooting, suggestions, or support for printer repairs. We do offer an in-person evaluation and repair service through our local diagnostic facility: printer repair service (https://bchtechnologies.com/printer-repair-service). Because demand stays high, we operate on a first-come, first-served basis, and it may take a few weeks before we can schedule a drop-off. Our services are structured to repair either an entire printer or specific parts, with clear instructions on how to proceed. We also recognize our rates aren't the most economical, so we strongly recommend self-help through online research first. You can start by checking YouTube or visiting our channel homepage, BCH Technologies on YouTube (https://youtube.com/@bchtechnologies). To find the most relevant videos, use the search icon next to "About" on the right-hand side of the menu bar. I receive dozens of questions every day asking if we have a video for a very specific symptom, and after creating videos for the past nine years, it's difficult to remember every single one-so YouTube's search tool is the fastest and most accurate way to locate what you need. YouTube may also suggest helpful videos from other channels that match your exact situation.

Thank you again for reaching out and for supporting BCH Technologies. I hope you're able to get all channels printing again soon.