Siemens A5E00755411 — SINAMICS S120 PSBC2 Power Supply Board | Genuine OEM Spare | New Boxed

When a SINAMICS S120 booksize drive shuts down and won't recover after power cycling, the internal power supply board is one of the first components engineers check. The A5E00755411 — designated PSBC2 (Power Supply Board Compact 2) — is the OEM replacement board that restores the internal electronics supply rail in affected S120 booksize modules, getting production back online without the cost and lead time of a complete module replacement.

This listing is for a genuine Siemens A5E00755411, new and boxed. Not refurbished, not a third-party reproduction.

What Is the A5E00755411 PSBC2?

The PSBC2 is an internal PCB assembly within SINAMICS S120 booksize format power units. Its job is straightforward but critical: it converts the incoming DC bus voltage into the regulated low-voltage DC supplies (primarily 24V and auxiliary rails) that power the module's own control electronics — the gate driver circuitry, status LEDs, DRIVE-CLiQ interface, fan control, and temperature monitoring circuits.

In other words, the PSBC2 is what keeps the "brain" of the power module alive. The high-voltage power stage handles motor output, but without a functioning PSBC2 delivering stable internal supply voltages, the module cannot initialize, cannot communicate over DRIVE-CLiQ, and will not respond to enable signals from the CU320-2 Control Unit.

This distinction matters for troubleshooting: a failed PSBC2 typically manifests as a module that shows no LED activity at power-up, fails to appear in the DRIVE-CLiQ topology scan, or generates persistent F06010 (power supply fault) or similar electronics supply-related alarms — even when the DC link voltage and motor output wiring are intact.

Compatible S120 Platform — Where This Board Is Used

The A5E00755411 PSBC2 is a spare part for the SINAMICS S120 drive system, Siemens' high-performance modular servo and vector drive platform used extensively in machine tools, packaging lines, printing presses, automotive assembly, and industrial robots.

SINAMICS S120 operates as a multi-axis system: a single Control Unit (CU320-2 PN or CU320-2 DP) manages multiple booksize Motor Modules and Line Modules interconnected via DRIVE-CLiQ. Each booksize module contains its own internal electronics supply, and the PSBC2 is the power supply board serving that function.

The S120 booksize format covers a wide power range — from compact double-axis modules handling 3A + 3A up to single-axis modules rated at 200A+. Across this range, the internal power supply architecture requires a compact, reliable DC-to-DC converter board, and the PSBC2 series serves this role. The A5E00755411 (PSBC2) is the specific variant for relevant booksize modules in the S120 range; always cross-reference with the module's service documentation or the physical board label on the unit being repaired before ordering.

Why Replace the Board Rather Than the Whole Module?

It's a fair question, and the answer usually comes down to economics and lead time. A complete SINAMICS S120 booksize Motor Module — depending on the axis current rating — typically costs several thousand dollars new from Siemens distribution. An internal power board like the A5E00755411 is a fraction of that price.

More importantly, complete modules for specific S120 configurations can have extended lead times through official channels, especially for older installations. For a machine sitting idle waiting for a drive module, a week-long wait is a significant production loss. Sourcing the specific failed board — when the rest of the module's power stage, IGBTs, and mechanical assembly are confirmed intact — is a cost-effective path back to operation that experienced drive repair technicians have relied on for years.

The S120 Equipment Manuals (available on Siemens Industry Online Support) include documented procedures for replacing power supply boards in booksize chassis power units, acknowledging this as a supported service operation for qualified personnel.

Key Fault Symptoms Pointing to PSBC2 Failure

Not every S120 fault requires a PSBC2 replacement, but certain symptom patterns make it a likely candidate:

The clearest sign is a booksize module with no LED indication whatsoever at power-up, despite confirmed DC bus voltage at the module terminals. If the module's DRIVE-CLiQ port is dark and the CU320-2 cannot detect it in the topology scan, the internal electronics supply has almost certainly failed — and the PSBC2 is the component supplying that rail.

Secondary indicators include modules that appear intermittently in the topology (suggesting marginal internal supply voltage under load), repeated F06010 power supply fault codes that clear briefly and then return, or modules that run normally when cold but fail after thermal cycling — a pattern consistent with dry solder joints or failing capacitors on the internal power board.

Fault codes F30001 (overcurrent) and F30002 (DC link overvoltage) are power unit faults but originate from the power stage, not the PSBC2. If those faults are present with normal LED activity on the module, the PSBC2 is likely not the cause.

Part Details

Parameter	Information
Siemens Part Number	A5E00755411
Board Designation	PSBC2
Application	SINAMICS S120 booksize drive modules
Function	Internal electronics power supply board
Condition	New, original, boxed
Brand	Siemens
Compatibility	Cross-reference with S120 booksize module service documentation

⚠️ Compatibility verification note: Before ordering, confirm the A5E00755411 part number against the physical label on the board being replaced in your specific S120 module. Siemens has produced multiple PSBC variants across the S120 booksize range (PSBC, PSBC2, etc.), and the correct replacement must match the installed board. The A5E number printed on the existing board is the definitive reference.

Handling and Installation Notes

The PSBC2 is a PCB assembly containing sensitive electronic components including electrolytic capacitors, DC-DC converter stages, and signal isolation circuits. Standard ESD handling precautions apply — use a grounded wrist strap and ESD-safe workspace when handling the board outside its packaging.

Before replacing the PSBC2 in a live S120 module, the module must be fully de-energized: DC link voltage must be discharged (the S120 booksize modules include pre-charge circuitry, but the DC link capacitors retain voltage after AC input disconnection — verify with a calibrated meter before touching internal components). Siemens specifies a minimum waiting period after power-down before working inside modules; consult the relevant S120 Equipment Manual for the specific module type.

This is a component-level replacement intended for qualified drive service technicians. It is not a plug-in replacement in the same sense as swapping a complete module.

❓ FAQ — Siemens A5E00755411 PSBC2 Power Supply Board

Q1: What exactly is the A5E00755411, and what drive does it belong to?

The A5E00755411 is the PSBC2 power supply board — an internal PCB used in SINAMICS S120 booksize format drive modules. It is not a complete inverter or drive. It is a service spare part: the internal board that generates the regulated low-voltage supply rails (including 24V) powering the module's own control electronics. When this board fails, the module loses internal power, goes dark, and cannot communicate on DRIVE-CLiQ — even if the DC link and IGBT power stage are healthy. It is used in Siemens SINAMICS S120 systems, which are widely deployed in machine tools (CNC machining centers, grinding machines), packaging equipment, printing presses, and multi-axis servo applications across manufacturing industries.

Q2: How do I confirm this is the right part for my S120 module?

The safest method is to physically check the part number label on the board currently installed in your module. Siemens uses "A5E" prefixed part numbers (internal assembly numbers) on PCB components, and the correct replacement must match the A5E number on the installed board. The A5E00755411 should be verified against the failed board's label — do not rely solely on module model number matching without this check, as Siemens has produced multiple PSBC variants across S120 booksize generations. The S120 Equipment Manual for your specific module type (available at support.industry.siemens.com) also lists spare parts with their A5E numbers.

Q3: Can I replace the PSBC2 myself, or does it require a Siemens service engineer?

Board-level replacement in S120 modules is a documented service procedure, but it requires specific safety precautions and technical competence. The primary concern is the DC link voltage: S120 booksize modules store significant energy in the DC link capacitors, which remain charged for a period after input power is removed. Siemens specifies mandatory de-energization waiting times before internal access — working inside a module before this period elapses risks lethal electric shock. Beyond safety, the replacement requires correct ESD handling and reassembly per the module's service documentation. Experienced drive service technicians perform this regularly; it is not typically appropriate for personnel without specific training on SINAMICS S120 hardware.

Q4: What symptoms suggest the PSBC2 has failed rather than another S120 component?

The most diagnostic symptom is a booksize module with zero LED activity at power-up, despite confirmed DC bus voltage at the module's DC link terminals. If the DRIVE-CLiQ port shows no link activity and the CU320-2 cannot see the module in the topology scan, internal electronics supply failure (PSBC2) is the leading cause. This is distinct from power stage faults (F30001 overcurrent, F30002 DC overvoltage, F30004 heatsink overtemperature), which show LED activity and DRIVE-CLiQ communication. If the module communicates but throws power unit fault codes, the PSBC2 is likely healthy and the fault is in the power stage itself. Intermittent disappearance from the topology scan — particularly after the module warms up — can also indicate a marginal PSBC2 with temperature-sensitive components.

Q5: Is this a new board or refurbished?

This listing is for a new, original, boxed Siemens A5E00755411. New and genuine — not refurbished, not third-party reproduction, not pulled from a scrapped module. For a component going into a production machine, using a new OEM board rather than a refurbished one eliminates the question of prior failure history and residual component aging (particularly relevant for electrolytic capacitors, which degrade with thermal cycling even without visible failure).

Q6: What is the difference between PSBC and PSBC2?

The PSBC and PSBC2 designations indicate different generations of the internal power supply board used in S120 booksize modules. They are not interchangeable — the PSBC2 (A5E00755411) is the second-generation variant with revised circuitry. The correct board is determined by the specific module variant being serviced, not by user preference. Always match the A5E number on the replacement board to the A5E number on the board being replaced. If you are unsure which generation is installed in your module, the physical label on the existing board is the authoritative reference.

Q7: Can I use this board with SINAMICS S120 chassis format modules, or only booksize?

The A5E00755411 PSBC2 is associated with the booksize format S120 modules. Chassis format S120 modules (which handle higher power ratings and have a different physical construction) use different internal power supply boards. The format distinction in S120 is significant — booksize and chassis modules have entirely different internal architectures, cooling methods, and spare part ecosystems. If you are working on a chassis format module, the replacement board part number will differ. Verify against the physical label on the board in your specific module.

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