Description
⚙️ Product Overview
The YAMATAKE HONEYWELL 51402755-100 is a K4LCN processor board / circuit card used in Honeywell legacy process-control systems. It is identified as a K4LCN processor card and is associated with the K4LCN architecture used within Honeywell Local Control Network (LCN) equipment.
The 51402755-100 is also identified as a K4LCN K4SS motherboard with 4 MW, while separate memory modules can be fitted depending on the system configuration. This makes accurate identification of the board revision and memory configuration important when selecting a replacement.
This is a legacy industrial automation spare suitable for maintenance, repair, system restoration, and critical spare inventory.
🔧 Key Features
- 🧠 K4LCN processor / control board architecture
- 🏭 Designed for Honeywell legacy industrial automation systems
- 🔌 Associated with Honeywell LCN-based control architecture
- 💾 Supports a dedicated memory-board configuration
- 🧩 4 MW K4SS motherboard configuration
- 🔄 Suitable for replacement of compatible legacy processor boards
- 🛠️ Useful for DCS maintenance and system restoration
- 📋 Part number: 51402755-100
- 🔖 K4LCN / K4LCN-4 identification
- 📦 Suitable for long-term critical spare inventory
📊 Technical Datasheet
| Parameter | Details |
|---|---|
| Brand | YAMATAKE HONEYWELL |
| Model | 51402755-100 |
| Series | K4LCN |
| Product Name | K4LCN Processor Board |
| Product Type | Processor / Control Circuit Board |
| Architecture | K4LCN / K4SS |
| Memory Configuration | 4 MW motherboard configuration |
| Associated Memory | Configuration-dependent K4LCN memory module |
| Application | Honeywell Legacy Process Control Systems |
| Product Status | Legacy / Industrial Automation Spare |
🧠 K4LCN Processor Function
The K4LCN board forms part of the processing architecture of compatible Honeywell control equipment. The board should be considered a dedicated system component rather than a general-purpose PLC CPU.
The 51402755-100 is documented as a K4LCN board that does not include the DIMM memory board in its base assembly. Associated K4LCN memory boards include dedicated memory modules that must be matched to the applicable hardware configuration.
🔗 System Integration
In a typical legacy Honeywell architecture, the processor board works together with other LCN-related assemblies and system interfaces.
A simplified architecture can be represented as:
Honeywell Control System → K4LCN Processor → LCN Interface / Node Electronics → Control & Monitoring Functions
When replacing the board, technicians should compare:
- 51402755-100 part number
- K4LCN identification
- Hardware revision
- Memory-board configuration
- Board markings
- Connector arrangement
- Existing chassis configuration
- Associated LCN interface boards
The K4LCN board should be replaced only with a configuration confirmed to be compatible with the installed system.
🧰 Installation & Commissioning
- Place the control system in the approved maintenance state.
- Isolate power according to the applicable Honeywell system procedure.
- Record the original board number and revision.
- Verify the replacement is 51402755-100 K4LCN.
- Check the associated memory board before installation.
- Inspect the backplane and connectors for contamination or physical damage.
- Install the board carefully and ensure proper seating.
- Restore system power according to the approved startup procedure.
- Check processor and system status indications.
- Verify LCN communication and system diagnostics.
- Confirm normal control-system operation before returning the equipment to service.
🔍 Troubleshooting Guide
Processor board does not initialize:
Check board seating, backplane connections, system power and hardware identification. A mismatched memory configuration can also affect system operation.
LCN communication fault appears after replacement:
Inspect the associated LCN interface hardware and communication connections. Confirm that the replacement board is appropriate for the installed node configuration.
System reports memory-related errors:
Check the installed K4LCN memory module and verify that it matches the processor-board configuration.
Intermittent processor faults:
Inspect connectors, backplane contacts and the board for oxidation, contamination or signs of component deterioration.
Replacement does not operate as expected:
Compare the original and replacement board revision, processor identification, memory configuration and system hardware before troubleshooting further.
🔧 Maintenance Recommendations
For legacy Honeywell installations, electronic processor boards should be handled as ESD-sensitive equipment.
Recommended practices include:
- Store spare boards in ESD-protective packaging.
- Keep boards away from moisture, dust and conductive contamination.
- Record the complete part number and revision in the spare-parts database.
- Inspect connectors before installation.
- Avoid unnecessary handling of exposed components.
- Maintain compatible memory modules together with processor boards where practical.
- Keep at least one tested spare for critical legacy control nodes.
📦 Replacement Considerations
The 51402755-100 has been identified as a K4LCN K4SS motherboard with a 4 MW configuration. Documentation also identifies 51403519-160 as a later K4LCN K4SDR motherboard that replaces 51402755-100 in certain architectures. This does not mean the newer board is automatically interchangeable in every installation; the complete system configuration must be checked.
For procurement, provide the following information whenever possible:
51402755-100 + K4LCN + hardware revision + memory configuration
This provides a much safer basis for compatibility checking than the part number alone.
❓ Frequently Asked Questions
Q: What is Honeywell 51402755-100?
A: It is a K4LCN processor/control board used in Honeywell legacy industrial automation equipment.
Q: Is 51402755-100 a PLC CPU?
A: It is a dedicated Honeywell K4LCN processor board rather than a conventional standalone PLC CPU.
Q: What does K4LCN mean?
A: K4LCN identifies a Honeywell LCN-related processor-board architecture used in legacy control-system equipment.
Q: Does 51402755-100 include the memory board?
A: The documented 51402755-100 configuration does not include the DIMM memory board. Compatible memory modules are specified separately depending on the system configuration.
Q: What memory is associated with this board?
A: K4LCN memory modules are available in configuration-specific versions. The exact memory should be verified against the installed system.
Q: Can 51403519-160 directly replace 51402755-100?
A: It is documented as a replacement in certain K4LCN configurations, but system-level compatibility must be confirmed before substitution.
Q: Is 51402755-100 suitable as a spare?
A: Yes. It is particularly useful as a maintenance spare for legacy Honeywell systems where continued operation depends on maintaining the original control architecture.
🔗 10 Related Honeywell Models / Spare Parts
- Honeywell 51401946-100 K4LCN Motherboard
- Honeywell 51403519-160 K4LCN K4SDR Motherboard
- Honeywell 51201793-160 K4LCN DIMM Memory Board
- Honeywell 51201793-800 K4LCN DIMM Memory Board
- Honeywell 51401551-801 K2LCN Board
- Honeywell 51402615-800 K2LCN Board
- Honeywell 51400978-100 HMPU Node Processor Board
- Honeywell 51401291-100 LLCN Board
- Honeywell 51305072-100 CLCN A/B Board
- Honeywell 51107403-100 LCN I/O Board
✅ Product Summary
The YAMATAKE HONEYWELL 51402755-100 | K4LCN Processor PCB is a specialized legacy processor board for Honeywell industrial control architecture. Its K4LCN/K4SS design and associated memory configuration make it an important spare for maintaining compatible legacy control systems.
For replacement projects, verify the 51402755-100 part number, hardware revision, K4LCN identification, memory configuration, and installed LCN architecture before commissioning.
