Mitsubishi A2SHCPU CPU Module – Obsolete MELSEC A Series Spare Part

Technical Dossier

Product Details And Specifications

Mitsubishi A2SHCPU CPU Module – Obsolete MELSEC A Series Spare Part

DriveKNMS reviews sourcing options for this model through RFQ handling before quotation.

RFQ support for obsolete parts: Send the model number, required quantity and destination so DriveKNMS can confirm sourcing options before quotation.

Technical Specifications

Note: Electrical parameters such as program memory capacity, scan time, and I/O point counts vary by firmware revision. DriveKNMS does not publish unverified specifications. Contact us for unit-specific data sheets prior to purchase.

Solving the Discontinued Hardware Crisis

The MELSEC A Series was Mitsubishi Electric's workhorse PLC platform across heavy industry, automotive body shops, food processing lines, and utilities infrastructure throughout the 1980s and 1990s. Tens of thousands of these systems remain in active service globally — not because plant operators are unaware of the discontinuation, but because the cost and risk of migration outweigh the cost of maintenance, provided spare parts remain available.

The A2SHCPU sits at the center of this equation. It is the processing core of the control system. Every I/O module, every communication card, every HMI connection routes through this unit. When it fails, the entire line stops. There is no partial workaround. The system does not degrade gracefully — it halts.

Migrating away from the A Series to a current Mitsubishi iQ-R or iQ-F platform, or to a competitor's architecture, requires not only new hardware but a complete rewrite of ladder logic programs that may have been developed and refined over 20 or 30 years of production. Institutional knowledge embedded in those programs is frequently undocumented. The migration risk is real, and it is why experienced plant engineers prioritize securing a verified spare A2SHCPU over initiating a capital project.

How to extend your MELSEC A Series system life by 5 to 10 years at low cost:

Condition & Reliability Assurance

Sourcing obsolete industrial hardware carries inherent risk. DriveKNMS applies a structured 5-step inspection protocol to every A2SHCPU unit before it is offered for sale or shipment.

1. Visual and mechanical inspection. Physical examination of the PCB, connector pins, and housing for corrosion, impact damage, burn marks, or evidence of prior repair attempts. Units with compromised physical integrity are rejected at this stage.
2. Electrolytic capacitor assessment. Aged electrolytic capacitors are the primary failure mode in legacy PLC hardware stored for extended periods. Each unit is assessed for capacitor condition; units showing visible bulging, electrolyte leakage, or measured capacitance deviation are flagged for remediation or rejection.
3. Firmware version verification. The firmware revision is recorded and disclosed. Compatibility between firmware version and the target application is the customer's responsibility to confirm; DriveKNMS provides the version data to support that assessment.
4. Pin and connector integrity check. All backplane connector pins are inspected for oxidation, bending, and mechanical wear. Contact surfaces are cleaned where required.
5. Functional power-on test. Where test equipment permits, units are powered and observed for normal initialization behavior. Results are documented and available on request.

Key Features for System Maintenance

• Drop-in replacement. The A2SHCPU installs directly into the existing A Series base unit without mechanical modification. No new backplane, no new I/O wiring.
• No reprogramming required. Existing ladder logic programs transfer directly. There is no software migration, no logic rewrite, and no revalidation of control sequences — provided the replacement unit carries a compatible firmware revision.
• Avoids engineering reconstruction costs. A replacement CPU preserves the entire existing control architecture. The alternative — a platform migration — involves engineering hours, new hardware procurement, software development, and commissioning time that collectively represent costs orders of magnitude higher than a spare part.
• Maintains production continuity. A verified spare on the shelf converts a potential multi-week production halt into a same-shift swap. The operational value of that capability is not captured in the price of the part.

How do I know the unit is genuine and not counterfeit?
All units stocked by DriveKNMS are sourced through documented supply channels. Physical markings, label formats, and PCB characteristics are cross-referenced against known-genuine references. We do not source from unverified secondary markets. Inspection documentation is available on request.

Can DriveKNMS source other MELSEC A Series modules?
Yes. Contact us with your full bill of materials for the A Series system. We maintain or can source a range of A Series I/O, communication, and power supply modules in addition to CPU units.