A servo trouble alarm on a running unit forces a fast judgment call, and replacing the wrong component costs a second outage window. This page covers the IS200TSVOH1BCC — GE's TSVO Servo Terminal Board, base number IS200TSVOH1B at the CC revision, supplied used, cleaned, and tested — together with the checks that tell you whether the terminal board is actually the component to replace.

First Response to a Servo Regulator Alarm

• Establish which loop and which channel. An alarm confined to one redundant channel suggests electronics or cabling on that channel; an alarm on all channels suggests the valve, the LVDT, or the field wiring they share.
• Test the valve circuit at the board. Coil resistance measured at the TSVO terminals catches opens, shorts, and grounds without dismantling anything.
• Verify LVDT excitation and feedback. Most regulator feedback out-of-limits conditions trace to the transducer or its conductors, not to the termination hardware.
• Reseat the processor cables. The runs to the servo processor pass through connectors that work loose over years of thermal cycling.
• Condemn the board last — unless it shows physical damage or the system flags its ID chip, which is a fault that genuinely originates on the TSVO.

What the TSVO Terminal Board Does

In the Mark VI architecture the TSVO is the termination point for two electro-hydraulic servo valve loops — the actuators that stroke steam and fuel valves. Servo drive current leaves through this board, and LVDT position feedback returns through it, giving the VSVO servo processor everything it needs to close both position loops. Connector JR1 carries signals in simplex systems; JR1, JS1, and JT1 distribute them in TMR systems so the <R>, <S>, and <T> channels stay independent; and plugs JD1 and JD2 accept an external trip from the protection module so a shutdown command has a path to the valves that does not rely on the normal control chain.

Field Wiring on the TSVO: Terminals, Shields, and Gauge

GE-derived documentation describes two I/O terminal blocks on the board, each held by two screws and carrying 24 terminals that accept conductors up to #12 AWG, with a shield termination strip bonded to chassis ground immediately left of each block. For a swap, that layout is your friend: photograph the landed wiring before removal, move conductors block by block, and terminate every shield on the strip rather than leaving drain wires floating. Sloppy shield work after a board change is a classic source of position-feedback noise that gets misdiagnosed as a defective replacement.

Part Number Anatomy: IS200TSVOH1BCC

IS200 identifies the Speedtronic board series, TSVO the Servo Terminal Board function, H1B the hardware group and version, and CC the production revision. Match the group (H1B here) strictly — an H1A exists in the field and GE's public literature does not define the difference, so mixing groups is a risk we recommend against — and quote the revision so we can match or advise. The complete numbering framework is explained in our GE Speedtronic Part Number Decoder.

The Hardware Around This Board

The TSVO never works alone: the VSVO processor closes the loops in Mark VI racks, the protection module ties in through the JD1/JD2 trip plugs, and on Mark VIe systems the IS220PSVO I/O pack takes over the processor role, connecting the same style of terminal board to redundant Ethernet networks. Companion boards are listed in GE Mark VI IS200 Boards and the full range in GE Speedtronic Turbine Control Boards; if your plant straddles control generations, start with Mark V vs Mark VI: DS200 to IS200.

Send These Details with Your Quote Request

• The label string in full — IS200TSVOH1BCC — plus a photo if you can get one
• Turbine model and control system generation
• Mating electronics on the loop: VSVO card or PSVO pack
• Simplex or TMR configuration
• Quantity, and whether the unit is down or the need is planned

Get a Quote Within 24 Hours

Use the Request a Quote form and our team will reply inside 24 hours with availability and lead time. We accept purchase orders and ship DDP worldwide, so import duties and customs clearance are already handled when the board arrives. This unit's specific condition and warranty are stated in the table below.

General Information about the Product
Part Number	IS200TSVOH1B Mark VI IS200
Description	IS200TSVOH1B By General Electric IS200TSVOH1BCC Servo Terminal Board MK VI IS200
Condition	used Cleaned and Tested. With 1 Year Warranty.