The short answer: choose the supplier you can verify, not the one with the best brochure. Five things decide whether an LED project goes well — whether the factory builds the pitch you need from its own modules, whether its quality checks are documented before shipping rather than promised after, whether the person who signs the spec sheet owns the production line, whether spare parts are guaranteed for the life of the screen, and how the supplier behaves in the first 90 days after installation.
Everything below is a way to test those five things without flying to China.
Factory or trading company — does it actually matter?
Less than most buyers think, and more than suppliers admit.
A trading company can deliver a good 15 m² order: they aggregate modules from a factory, handle export paperwork, and often communicate better in English. The problems start at three points:
- Above roughly 50 m², when something goes wrong mid-production, you need a person who can walk onto the line.
- When you need a non-standard pitch or cabinet, because a trader has to ask someone else whether it is possible, and the answer degrades each time it is relayed.
- Year 3, when you need 40 replacement modules from a batch that is no longer current.
The practical test: ask for a video call on the production floor with the SMT line running, and ask them to pan to the machines that are placing LEDs. A factory can do this in ten minutes. A trader will offer a photo set instead.
The 12 questions that separate suppliers
| # | Ask | Why it matters | A good answer sounds like | Red flag |
|---|
| 1 | Which pitch and cabinet does this line come from — your own module or a bought-in one? | Bought-in modules mean no control over binning | Names the module, driver IC and the line | "Same as everyone's" |
| 2 | Who signs the spec sheet? | Accountability has a name | A process engineer, with a title | "Our engineer will confirm later" |
| 3 | What is your dead-pixel rate, measured on the finished cabinet? | The number that shows up in year 2 | A figure plus how it is measured | "Zero defects" |
| 4 | How many hours of aging before packing? | Catches early LED and driver failures | 72 h at rated brightness, with a log | "We test every unit" |
| 5 | Can I see a full aging report for a past order? | Proves the check is real | A redacted PDF with serials | Refuses, cites confidentiality |
| 6 | What are your replacement-part terms, in years? | Determines the screen's real lifespan | Written years, spare modules quoted in the contract | Verbal "we support forever" |
| 7 | Which driver IC and which LED brand are in this BOM? | The two components that decide quality | Specific part numbers | "High quality chips" |
| 8 | Is the cabinet steel, die-cast aluminium, or a mix — and what is the tolerance? | Drives flatness and seams | A tolerance in mm | "Industry standard" |
| 9 | What happens if the screen fails in month 2 — who pays freight? | The most common dispute | A stated policy, in writing | "We will handle it" |
| 10 | Can I speak to two customers who bought this exact model? | Reality check on the brochure | Two contacts, same product | "Our clients are confidential" |
| 11 | What is the MOQ for a repeat order of spare modules? | Tells you if year-3 support exists | Low or none | Full-container MOQ |
| 12 | Who owns the packing spec — do you crate for sea or air? | Most transit damage is packaging | A crate drawing with foam spec | "We pack very well" |
Ten good answers and two evasions is normal. Six evasions is a decision.
The numbers to require in writing
These are the parameters that predict how the screen looks and lasts. Ask for them per model, not per company, and ask for the measurement method alongside the value.
| Parameter | What to require | Why this one |
|---|
| Dead pixel rate | ≤ 3 per 10,000 pixels, measured on the finished cabinet | The threshold most warranty claims are fought over |
| Brightness uniformity | ≥ 97% across the module | Visible as patchy "clouds" on a white field |
| Cabinet flatness | ≤ 0.5 mm between adjacent cabinets | Shows up as dark seams at oblique angles |
| Grey scale | 14-bit processing or better | Determines whether shadows band |
| Refresh rate | ≥ 1,920 Hz for rental/broadcast, ≥ 3,840 Hz where cameras are close | Banding on video is almost always refresh |
| Power consumption | Max and average, per m² | Sizing the electrical supply is your cost |
| IP rating | IP65 front for outdoor, stated per face | See IEC 60529 for what the digits mean |
| LED binning | Single bin, or state the bin range | The real cause of colour shift between batches |
If a supplier cannot give you the measurement method, the number is marketing.
What a factory audit proves — and what it does not
A third-party audit (TÜV Rheinland, SGS, Intertek) tells you that a factory exists, has the equipment it claims, and runs some form of documented process. It does not tell you that your specific order will be built well.
Useful audits are process audits with a scope you choose: incoming LED inspection, SMT first-article approval, aging records, and final QC sampling. Ask for the audit report's scope page, not the certificate. A certificate with no scope is a logo.
Industry standards are a useful shortcut when you audit:ISO 9001for the quality system,IPC-A-610for solder-joint acceptability — that is where "looks fine" becomes a pass/fail.
Why your three quotes are not comparable
Almost every "quote comparison" spreadsheet compares different things. Put the quotes on the same basis first:
- Incoterm. FOB Shenzhen and DDP Chicago are not the same number: freight, duty and final delivery sit outside one and inside the other. Pick one basis and convert before you compare.
- What is in the price. Structure, cabinets, power supplies, receiving cards, spares, control software, commissioning.
- Spare allowance. A 2% allowance and a 5% allowance produce different per-m² prices and different year-2 costs. Neither is wrong; mixing them in one spreadsheet is.
- Warranty start. From shipment or from installation? Those are different dates, and the gap is your exposure.
- Packing. Flight case versus crate is a real line item on rental screens, and the one most often left out of a comparison.
A supplier that refuses to itemise is telling you the itemisation is where the margin hides.
Sample, aging, and pre-shipment inspection
Three checkpoints, in order, each cheap relative to the failure it prevents:
- Sample. One cabinet, not one module. Pay for it. Test it at the brightness you will actually run, for a week.
- Aging report. Before packing, request the aging log for your serial numbers — not a sample log.
- Pre-shipment inspection. A third-party pre-shipment inspection costs little relative to the order and covers the classic failures: dead pixels, cabinet flatness, colour mismatch between cabinets, missing accessories.
For context on how these checks map onto a real production line: Nationvision runs a 12,000 m² factory in Bao'an, Shenzhen with 22 placement machines and a TÜV Rheinland-audited process, which is the level of detail worth asking any supplier to document.
FAQ
How long does a typical LED display order take from China?
Standard cabinets commonly run two to four weeks in production; custom pitches and custom cabinet tooling take longer. Then add roughly four to six weeks door to door by sea to the US, or under a week by air — but air only makes sense on small volumes, because cabinet weight makes the freight economics collapse quickly.
Is a cheaper supplier worth it for a first order?
Only if the price difference is under about 10% and the specification is identical. Beyond that, the saving is usually extracted from LED binning, driver ICs, or the power supply — three places that fail in year 2, not week 1.
Should I buy from a trading company?
For orders under roughly 30 m² with a standard product, a good trading company is a reasonable choice. Above that, or for anything custom, you want direct access to the line.
How do I verify a supplier is a real factory?
Ask for a live video walk-through with the SMT line running, then match the company name on the business licence to the name on the export documents and the bank account. A mismatch in any of the three is the answer.
What deposit is normal?
30% deposit and 70% before shipment is standard. 50/50 is common on first orders. Anything demanding full payment before production, or refusing a pre-shipment inspection, is worth walking away from.
Does the LED brand actually matter?
Yes, more than the pitch. National-standards-grade LEDs from tier-one suppliers bin more tightly, which is why two screens with identical specifications can look different in year 3. Ask for the bin code, not just the brand.
The one-line version
Ask twelve questions, require eight numbers together with their measurement method, and inspect before you pay the balance. Suppliers who can answer all three parts are rare enough that the answer is the selection process.