Epson WF-3720 FFC Cable Mix-Up: Understanding AWM Markings, Matching by Length, and Safe Installation Tips

Question: I received cables for Order #S34225, but they don't match my Epson WorkForce Pro WF-3720 cables. Can I get an RMA and return label, and how do I handle the bends/adhesive alignment?

I received your shipment for Order #S34225, but the cables don't appear to be the correct ones for my Epson WorkForce Pro WF-3720. The cable I'm trying to replace is marked "SUMITOMO-V 0.5 mm pitch AWM 20624 80C 60V VW-1" and is 66 cm long. A second cable has similar markings and appears to be 6-pin.

The cables I received are marked "AWM 55402 BOC." I previously emailed on December 4 with the reference numbers (and an attachment). Caroline replied confirming the link to the cables I just received, but after measuring and comparing the corner bends used for installation, they don't match the original cable profile.

Please provide an RMA number and a return label so I can promptly return them. Also, I read your article about AWM markings not necessarily being a part number-if that applies here, how do I handle bending the cables to fit the printer's layout and make sure the adhesive aligns with the original securing points? For clarity, the cables were never inserted into the printer connections-only measured and compared.

Answer: 

1) Why the printed text (AWM 20624 vs AWM 55402) often does not mean "wrong part"

You're absolutely right to reference the AWM explanation you read. Markings like:

• AWM 20624 80C 60V VW-1

• AWM 55402 BOC

• SUMITOMO-V

• 0.5 mm pitch

...are typically wire/cable style certifications and manufacturing identifiers, not a guaranteed "Epson part number." In plain terms, the AWM code usually indicates a UL-recognized cable style/spec (temperature/voltage/flame rating), and the brand line (like Sumitomo) is the manufacturer. Two cables can perform identically in a printer yet carry different AWM style numbers due to different factories, materials, or certification families.

So, seeing AWM 55402 on the replacement does not automatically mean it's incompatible with the WF-3720.

2) How we sell and match these cables: primarily by length (and basic physical spec)

For FFC/FPC printer cables, we generally stock and sell them by length and common physical attributes (for example, pitch and number of conductors when specified). We do not sell them as "guaranteed WF-3720 OEM-bend-profile replacements," because Epson often uses custom fold geometries, adhesive placements, stiffeners, and routing paths that vary even among close variants.

That's why a cable can be correct electrically and dimensionally (length/pitch/contact type), but the factory bend points may not match your original cable's folds.

3) About your measurement concern: bends and "required profile" inside the printer

Your observation is important: many printers rely on cable folds to clear moving parts (carriage travel, hinges, scanner bed movement) and to prevent abrasion. However:

• A replacement FFC rarely ships pre-folded exactly like the original unless it's an OEM-labeled, model-specific harness.

• Most aftermarket or generic FFCs are shipped straight, and the installer must route and form them to match the machine layout.

That said, there are safe ways to evaluate and form an FFC, and there are unsafe ways that can ruin it quickly.

Safe handling rules for bending/forming FFC cables

• Never crease sharply like paper. A hard crease can crack internal conductors.

• Use gentle radius bends. If you must fold, make a smooth U-shaped bend rather than a tight V.

• Avoid bending right at the connector "gold finger" contact area or stiffener zone.

• Make sure the cable does not rub against sharp plastic edges or metal shields when the printer moves.

• If the cable must travel through a hinge area, keep slack controlled so it doesn't "saw" back and forth.

Because you specifically stated the cable was never inserted, you did the right thing by not forcing it into connectors. Forcing an incorrectly oriented or poorly routed FFC can damage a board-side connector or blow a fuse.

4) Adhesive alignment: why it won't always match, and what you can do

Many Epson assemblies use adhesive strips or anchor points to:

• keep the cable from vibrating loose,

• prevent it from contacting gears or rails,

• maintain the bend geometry.

A generic replacement cable may have:

• adhesive in different places,

• no adhesive,

• different stiffener placement.

If the adhesive does not line up with the original anchor points, the practical approach is usually to secure routing using the printer's existing guides/clips where possible, and only use non-permanent securing methods that won't stress the cable. We can't guide the exact method remotely because each printer's internal layout differs and the risk of damage is high if something is routed incorrectly.

5) Pin count and contact orientation still matter

You mentioned a second cable that "appears to be a 6-pin." That detail is important because cable compatibility is not just length:

• Number of conductors (pins)

• Pitch (e.g., 0.5 mm)

• Type (FFC vs FPC, thickness)

• Contact orientation (Type A same-side vs Type B opposite-side exposed contacts)

• Stiffener location relative to contacts

A cable can be 66 cm long and still be wrong if the pin count or contact orientation differs from your original. The safest method is to match those physical attributes exactly.

6) Regarding your RMA / return label request

For returns and RMAs, we can only process them through our standard customer service workflow so the team can verify the order details and the item condition based on our policy. Since you confirmed the cables were never inserted (only measured/compared), that's helpful context to include in the return request.

Addressing printer issues can be complicated because these problems are hands-on and highly dependent on the exact internal routing and physical condition of the machine. Because of that, 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). Due to high demand, we work on a first-come, first-served basis, and it may take a few weeks before we can schedule a printer drop-off. Our services are structured to repair either a whole printer or specific parts, with clear instructions on how to proceed. However, we recognize our rates aren't the most economical, so we strongly recommend self-help through online research. You can start on YouTube or by visiting BCH Technologies on YouTube (https://youtube.com/@bchtechnologies). Use the search icon next to "About" on the right-hand side of the menu bar to locate videos by keyword. I receive dozens of requests daily asking for a video on a specific topic, and after creating videos for the past nine years, it's difficult to remember every single one-so YouTube search is the fastest and most accurate method. Plus, YouTube may recommend other creators' videos that also apply to your situation.

Thank you again for reaching out and for being careful not to insert the cables before verifying fitment. We appreciate your support and your attention to detail, and we'll do our best to help through the proper service channels.