PLC · 8 min read · Updated October 2026
Mitsubishi MELSEC Legacy PLCs (A, QnA, AnS, FX2N): Spare Parts and Migration Guide
Thousands of machines across Asia still run on MELSEC-A, QnA, AnS and older FX controllers. Production of these families has ended — here is what that means, how to keep them running and how to move to Q, iQ-R or iQ-F without rebuilding the machine.
Mitsubishi MELSEC legacy PLCs are some of the most durable controllers ever built, which is exactly why so many are still in service long after production ended. According to Mitsubishi Electric, production of the MELSEC-A/QnA (large type) series was discontinued in September 2006, apart from some modules kept as spare products, and the repair service for these series ended at the end of September 2013. The small-type AnS/QnAS series followed; Mitsubishi Electric's regional information lists their production as terminated in September 2014. Older compact FX controllers such as FX1S, FX1N and FX2N have also been discontinued in favour of the FX3 and iQ-F (FX5) series.
Legacy MELSEC families at a glance
| Family | Status | Usual successor |
|---|---|---|
| MELSEC-A / QnA (large type) | Production discontinued September 2006 (some modules continued as spares); repair service ended September 2013 | MELSEC-Q, MELSEC iQ-R |
| MELSEC-AnS / QnAS (small type) | Production terminated September 2014 | MELSEC-Q, MELSEC iQ-R |
| FX1S / FX1N / FX2N (compact) | Discontinued | FX3 series, MELSEC iQ-F (FX5U / FX5UC) |
Status as published by Mitsubishi Electric. Always confirm a specific model number before planning.
What it means for a running plant
- No factory repair. For A/QnA, a failed module can no longer be sent back to Mitsubishi for repair; the plant depends on spares and third-party repair.
- Shrinking stock. CPUs, power supplies, base units and communication modules disappear from the market first.
- Old software and PCs. Programs were often written in GX Developer or older tools on PCs that are themselves near end of life — back up programs and comments now.
- Operator panels age too. Older GOT HMIs connected to these PLCs often fail before the PLC does.
Keep it running: the spare kit
- CPU for each CPU type, with the program and parameters backed up.
- Power supply and base unit (main and extension), or the compact main unit for FX machines.
- Network and communication modules (for example CC-Link, MELSECNET, serial) that link the PLC to drives, HMIs and other controllers.
- The I/O modules that fail most often on your machines, plus terminal blocks and cables.
- HMI (GOT) spare or a tested replacement panel with the converted screen project.
Discontinued parts come from remaining distributor stock and the surplus market, so documented origin is essential. Our obsolete parts service searches three layers of stock in parallel and only offers parts that pass traceability checks.
Migration paths
- A / QnA / AnS / QnAS → MELSEC-Q or iQ-R. Mitsubishi publishes transition guides for both the large and small types. Planning usually covers module-by-module replacement, I/O wiring re-use, network changes and program conversion.
- FX1S / FX1N / FX2N → FX3 or iQ-F (FX5U). For compact machines, an iQ-F main unit with built-in Ethernet usually replaces the old controller and adds remote access. Check I/O count, special adapters and positioning functions first.
- Programs. Older GX Developer projects can be opened in GX Works2 and converted to a newer CPU type; projects for iQ-F and iQ-R are engineered in GX Works3. Instructions, special relays and devices that differ between generations must be reviewed and tested.
A practical checklist
- List every machine with a legacy MELSEC PLC: model, I/O, networks, HMI.
- Back up programs, comments and parameters from the running CPUs.
- Rank machines by production impact and spare-part risk.
- Buy a minimum spare kit for machines that must run another 1–2 years.
- Select the target series and convert the program offline.
- Test with simulation or on a bench, then cut over during a planned stop with a fallback.
How HOANTRANTDH helps
From Hai Phong, Vietnam — close to many Japanese-owned factories — we source legacy MELSEC parts with an answer within 48 hours, supply current Mitsubishi Electric controllers such as the FX5U-32MR/ES, and our engineers carry out PLC migration and commissioning. Send your list of model numbers through the quote form.
Frequently asked questions
Is the Mitsubishi A series discontinued?
Yes. Mitsubishi Electric discontinued production of the MELSEC-A/QnA (large type) series in September 2006, except some modules kept as spares, and ended the repair service at the end of September 2013.
What replaces the Mitsubishi FX2N?
The FX3 series and the MELSEC iQ-F series (FX5U / FX5UC) are the usual successors. Check I/O count, special adapters and positioning before choosing.
Can I still buy MELSEC-A or FX2N parts?
Only from remaining stock and the surplus market. Availability differs by model, so check critical parts early and insist on documented origin.
Can old GX Developer programs be reused?
Yes, with conversion. GX Developer projects can be opened in GX Works2 and converted to a newer CPU type; differences in instructions and devices must be reviewed and tested.