Allen-Bradley 1336T-MCB-SP51B Spare for 1336 PLUS II

Allen-Bradley 1336T-MCB-SP51B Spare for 1336 PLUS II Automation

The Allen-Bradley 1336T-MCB-SP51B is the original main control board (MCB) designed for the 1336 PLUS II series AC variable frequency drives. As a critical spare part in industrial automation environments, this board governs the core drive logic, speed reference processing, fault diagnostics, and communication interface management within the 1336 PLUS II drive platform. Sourced as a genuine original component, the 1336T-MCB-SP51B is fully tested prior to shipment and backed by a 12-month warranty, making it a reliable choice for maintenance engineers managing planned shutdowns, emergency replacements, and long-term spare parts inventory strategies.

For maintenance and procurement engineers operating facilities with Allen-Bradley 1336 PLUS II drives, unplanned downtime caused by a failed main control board can halt entire production lines. Stocking the 1336T-MCB-SP51B as a ready spare eliminates extended lead times and reduces mean time to repair (MTTR). This component is particularly critical in aging drive systems where the original board may have accumulated years of thermal cycling, vibration stress, and capacitor degradation. Proactive replacement during scheduled maintenance windows — rather than reactive replacement after failure — is the recommended strategy for high-availability systems.

Spare Maintenance Table

Maintenance Planning for Continuous Operation

When replacing the 1336T-MCB-SP51B main control board, a thorough inspection of the surrounding drive components is essential to ensure the root cause of failure is addressed and to prevent repeat faults. Maintenance engineers should begin by verifying the integrity of the 1336 PLUS II power supply board, as an unstable DC bus voltage or ripple on the internal 5V/15V rails is a common cause of MCB failure. The gate driver board and IGBT power module should also be inspected for signs of thermal damage or gate signal irregularities before the new MCB is energized.

On the I/O side, inspect all analog and digital I/O terminal blocks for loose wiring, corrosion, or insulation breakdown — particularly on speed reference inputs (0–10V or 4–20mA) and enable/run command circuits. If the drive communicates via a SCANport or DPI communication adapter (such as the 1203-GU6 or 22-COMM-E), verify adapter firmware compatibility with the replacement MCB revision. Mismatched firmware versions between the MCB and communication adapter are a known source of fault codes after board replacement.

For drives integrated into a broader control architecture, check the PLC output module supplying the drive’s run/stop and speed reference signals — a failed transistor output on a 1756-OB16E or similar ControlLogix output card can cause repeated MCB stress. Inspect signal isolators on analog reference lines to confirm they are within calibration range. Review the condition of input line fuses and MOV surge suppressors on the drive’s incoming power terminals, as transient overvoltage events are a leading cause of control board damage in industrial environments.

In control cabinets housing multiple drives, also inspect terminal strips and DIN rail mounted relay modules for contact wear, particularly on interlock and fault reset circuits. If the system includes a 1336-GM1 or 1336-BDB series dynamic braking module, verify its resistor and chopper circuit integrity, as braking faults can back-feed voltage spikes into the control board. Finally, confirm that cabinet cooling fans and heat exchanger filters are clean and operational — thermal management is the single most impactful factor in extending MCB service life in high-cycle applications.

Site Replacement Workflow

Replacing the 1336T-MCB-SP51B on-site is a straightforward procedure when proper precautions are followed. Begin by documenting the existing drive parameters using DriveExplorer or Studio 5000 Logix Designer — upload and save the full parameter file before powering down, as some parameter sets are stored on the MCB itself and will be lost upon board removal. Power down the drive, lock out/tag out (LOTO) the incoming supply, and discharge the DC bus capacitors per the 1336 PLUS II installation manual (minimum 5-minute wait after power removal).

Remove the front cover and carefully disconnect the ribbon cables and connector harnesses from the existing MCB. Note the orientation and routing of all cables before removal. Install the replacement 1336T-MCB-SP51B, reconnect all harnesses, and verify seating of the SCANport/DPI connector if applicable. After power-up, restore the saved parameter file and perform a no-load test run to confirm speed reference tracking, fault-free operation, and correct I/O response before returning the drive to production service.

This workflow minimizes downtime to under two hours in most field scenarios, compared to days or weeks for OEM repair or new drive procurement. Maintaining one 1336T-MCB-SP51B per critical drive in your spare parts inventory is the most cost-effective strategy for sustaining aging 1336 PLUS II installations and extending system life well beyond the original product lifecycle.

Spare Parts Support FAQ

Q1: Is the 1336T-MCB-SP51B compatible with all 1336 PLUS II drive ratings?
The 1336T-MCB-SP51B is the standard main control board for the 1336 PLUS II series across most voltage and current ratings. However, compatibility should be verified against the drive’s catalog number and existing MCB revision label, as certain high-power or special-option variants may use a different MCB suffix. Contact our technical team with your full drive catalog number for confirmation before ordering.

Q2: What pre-shipment testing is performed on this spare part?
All 1336T-MCB-SP51B units undergo functional electrical testing prior to shipment, including power-on verification, communication interface check, and visual inspection for component damage. Units are packed in anti-static ESD packaging with individual test records available upon request. The 12-month warranty covers functional failure under normal operating conditions.

Q3: How should I manage long-term spare parts inventory for aging 1336 PLUS II systems?
For facilities operating five or more 1336 PLUS II drives, we recommend maintaining a minimum of one 1336T-MCB-SP51B per site, supplemented by a power supply board and gate driver board as secondary spares. Given that the 1336 PLUS II series has reached end-of-life status with Rockwell Automation, sourcing and stocking critical boards now is strongly advised, as market availability will continue to decline. We offer long-term supply agreements for customers requiring guaranteed stock over multi-year horizons.

Q4: Can this board be used to replace a failed MCB in a drive that shows a “Hardware Fault” or “Control Board Fault” code?
Yes. Fault codes such as F002 (Control Board Fault), F048 (Hardware Fault), or persistent non-resettable faults that survive parameter reset are strong indicators of MCB failure in the 1336 PLUS II. After replacing the board, clear all faults, restore parameters, and perform a controlled test run. If faults persist after MCB replacement, the power supply board or gate driver should be investigated as secondary failure points.

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