Allen-Bradley 1336-PB-SP2B Original Industrial Spare 1336 PLUS II Compatible

Product Overview

Allen-Bradley 1336-PB-SP2B Original Industrial Spare 1336 PLUS II Compatible: System Stability and Industrial Spare Parts Maintenance Value

The Allen-Bradley 1336-PB-SP2B (Part No. 74101-502-51) is an original Precharge PC Board engineered specifically for the 1336 PLUS II series AC variable frequency drives. In industrial facilities where continuous production uptime is non-negotiable, the precharge circuit board plays a foundational role in protecting the drive’s DC bus capacitors from inrush current during power-on sequences. A failed or degraded precharge board is one of the most common root causes of drive fault codes, nuisance tripping, and unplanned shutdowns in 1336 PLUS II installations. Stocking a verified original replacement is not a luxury — it is a core element of any responsible maintenance strategy.

Whether you are managing a legacy automation system in a food processing plant, a water treatment facility, a paper mill, or a discrete manufacturing line, the 1336 PLUS II drive remains a workhorse in countless control cabinets worldwide. Rockwell Automation’s 1336 PLUS II platform has an extensive installed base, and sourcing original spare boards like the 1336-PB-SP2B ensures that your replacement maintains full electrical compatibility with the existing drive hardware — no firmware conflicts, no parameter re-mapping, no integration risk.

Critical Technical Specs Table

Preventive Maintenance Strategy

A precharge board failure rarely occurs in isolation. In most field cases, technicians who respond to a 1336 PLUS II drive fault discover that adjacent components have also been stressed by the same electrical event — whether it is a power surge, a capacitor aging issue, or a cooling failure that caused thermal stress across the power section. A disciplined preventive maintenance approach treats the 1336-PB-SP2B replacement as the starting point of a broader inspection, not the end of it.

During the same maintenance window, it is strongly advisable to inspect and, where appropriate, proactively replace the 1336-PB-SP2A Precharge Resistor Assembly, which works in tandem with the precharge board to limit inrush current. If the resistor assembly has been in service for more than three years, replacement alongside the board is a cost-effective decision that avoids a second shutdown within months.

The drive’s power supply board (1336-PB-SP1A or equivalent) should be checked for output voltage stability, as an unstable internal power supply can cause erratic precharge behavior and false fault codes that are often misdiagnosed as precharge board failures. Similarly, the gate driver board and IGBT power module within the 1336 PLUS II should be visually inspected for signs of carbon tracking, discoloration, or cracked solder joints — conditions that frequently accompany precharge circuit stress.

On the control side, verify the integrity of the 1336-MOD-A2 or 1336-MOD-B2 communication adapter modules if the drive is integrated into a DeviceNet or Remote I/O network. Communication module faults can mask underlying drive hardware issues and complicate fault diagnosis. While the cabinet is open, inspect all control terminal wiring and signal cables connecting the drive to the PLC — loose or corroded terminals on the 1336 PLUS II’s control board connector strip are a common source of intermittent faults.

For facilities running multiple 1336 PLUS II drives, a recommended inventory strategy is to maintain at least one spare 1336-PB-SP2B precharge board, one spare power supply board, and one spare control board assembly per drive family. This three-board spare kit approach covers the majority of field-replaceable failure modes and can reduce mean time to repair (MTTR) from days to under two hours. Additionally, stocking spare 24VDC control power fuses and DC bus fuse assemblies appropriate to the drive’s horsepower rating ensures that a simple fuse failure does not extend downtime while waiting for parts.

If the 1336 PLUS II drives in your facility are connected to a Rockwell Automation PLC-5 or SLC 500 controller via Remote I/O, it is worth scheduling a parallel inspection of the 1771-ASB Remote I/O Adapter and associated 1771 I/O rack backplane. These legacy components share the same maintenance lifecycle as the 1336 PLUS II and are equally critical to system continuity. Proactive replacement of aging backplane components prevents cascading failures that can take an entire production line offline.

Strategic Replacement Solutions

The 1336-PB-SP2B is a direct OEM replacement for the original precharge PC board installed in 1336 PLUS II drives at the time of manufacture. Unlike aftermarket alternatives, an original board eliminates compatibility risk — the component is designed to the same electrical tolerances, uses the same connector footprint, and requires no firmware or parameter changes after installation. This is particularly important in regulated industries such as pharmaceuticals, food and beverage, and utilities, where change management documentation requirements make aftermarket substitutions administratively burdensome.

For facilities managing aging 1336 PLUS II installations where the original drive is approaching end of supportable life, stocking the 1336-PB-SP2B as part of a system life extension strategy is a proven approach to deferring capital expenditure on new drive platforms. A single precharge board replacement can restore a drive to full operational status and extend its service life by three to five years, delivering a return on investment that far exceeds the cost of the spare part.

When planning a replacement, always cross-reference the drive’s nameplate data and the existing board’s part number label before ordering. The 1336 PLUS II was produced across multiple frame sizes and voltage ratings, and while the 1336-PB-SP2B covers a broad range of configurations, confirming the sub-part number (74101-502-51) against your drive’s bill of materials ensures a precise fit. Our technical team is available to assist with compatibility verification prior to shipment.

All units are dispatched with pre-shipment functional testing documentation and are covered by a 12-month warranty from the date of purchase. Fast international shipping is available, with most orders processed within 1–2 business days.

Support FAQ

Q1: How do I confirm the 1336-PB-SP2B is compatible with my specific 1336 PLUS II drive?
Locate the drive’s nameplate on the front of the unit and note the catalog number and series letter. Cross-reference the existing precharge board’s part label (74101-502-51) inside the drive. If you are unsure, contact us with the full drive catalog number and we will confirm compatibility before shipment.

Q2: What is the recommended inventory quantity for a facility running multiple 1336 PLUS II drives?
As a general guideline, maintain one spare precharge board per every three to five drives in service. For critical production lines where downtime cost is high, a one-to-one spare ratio is advisable. Bulk pricing is available for multi-unit orders.

Q3: What pre-shipment testing is performed on the 1336-PB-SP2B?
Each board undergoes functional electrical testing prior to dispatch to verify circuit integrity and component health. Units that do not pass testing are not shipped. A 12-month warranty covers any defects in materials or workmanship from the date of purchase.

Q4: Can this board be installed on-site by a maintenance technician, or does it require a specialist?
The 1336-PB-SP2B is a field-replaceable unit designed for on-site installation by qualified maintenance personnel familiar with VFD servicing procedures. Always de-energize the drive and follow Rockwell Automation’s lockout/tagout procedures before opening the drive enclosure. Allow the DC bus to fully discharge before handling internal components.