What the PSVO does in a GE Speedtronic Mark VIe system

Inside a Mark VIe turbine control, the servo output pack is what turns a position command into real hydraulic motion. This IS220PSVOH1A sits between the IONet Ethernet network(s) and the TSVO servo terminal board, and its WSVO servo driver closes up to two servo valve position loops — the loops that stroke fuel, inlet-guide-vane, and steam control valve actuators. One or two Ethernet connections tie it to the controller; a processor board with local power, flash, RAM, and an internal temperature sensor pairs with the servo acquisition board to do the work. Setup and monitoring live in ToolboxST, where the pack can be set to auto-reconfigure after a replacement.

Because it is a distributed pack, the PSVO mounts directly on the TSVO board rather than in a card rack, and it reports its own health back to the controller. That makes the faceplate LEDs (PWR, ATTN, the ENet link/status indications, and the ENA enables) and the ToolboxST alarm list your first and best diagnostic tools.

Diagnosing a suspected servo output failure

Servo faults are the classic case where the pack gets blamed for something upstream or downstream of it. If an actuator will not follow demand, spend a few minutes ruling out the usual suspects before ordering a replacement IS220PSVOH1A:

• Servo valve and coils: a contaminated or sticking valve, or an open or shorted coil, behaves like a dead output even though the drive electronics are healthy.
• LVDT/LVDR feedback: the position loop needs valid feedback to close. A degraded LVDT, wet connector, or broken wire produces hunting, drift, or a runaway that mimics a pack fault.
• TSVO terminal board and field wiring: loose landings, corrosion, or a failed board component can interrupt drive or feedback while the pack itself tests fine.
• IONet and power: a network cable, switch port, or power-feed problem can drop the pack offline in ToolboxST; the PWR and ENet LEDs tell you which.

The honest rule of thumb: if the same symptom follows the valve rather than the pack, or if only feedback (not drive) looks wrong, the money is usually on the valve, wiring, or terminal board. Confirm with ToolboxST diagnostics before you pull a pack from a running unit.

New surplus factory package: what the condition means here

This particular IS220PSVOH1A is offered as new surplus in the factory package (NSFP): unused stock in original packaging, which suits a fresh shelf spare or a like-for-like replacement without refurbished history. The exact condition and warranty for this unit are stated in the table below; we do not overstate condition, so please read it as written.

Suffix, revision, and matching your existing pack

The string breaks down as IS220 (Mark VIe distributed I/O platform) plus PSVO (servo output function) plus H1A (hardware revision and variant). A later H1B revision also exists. Rather than assume any two revisions are drop-in equivalents, match the suffix to what is installed and verify against your ControlST/ToolboxST version. Our GE Speedtronic Part Number Decoder explains how each character maps to a hardware attribute.

Cross-references and companion boards

If you keep a full Mark VIe spares kit, the PSVO usually sits next to analog, discrete, and protection packs on the same IONet. See the GE Speedtronic Turbine Control Boards and GE Mark VI IS200 Boards collections for companion hardware, and the Mark V vs Mark VI: DS200 to IS200 guide if you are comparing servo handling across control generations.

Building your quote request

Give us these details and we can confirm the correct unit quickly:

• Full part number and suffix (IS220PSVOH1A) plus the printed board revision.
• A photo of the pack label.
• Turbine model and control generation (Mark VIe or Mark VI).
• Quantity and required timing, including any outage deadline.

Get your IS220PSVOH1A quote in 24 hours

Send the information above through Request a Quote and we will respond within 24 hours with availability and a formal quotation. We ship worldwide on DDP terms and accept purchase orders from qualified buyers, so a quote request is the fastest way to lock in this unit for your system.