Every valve a Mark VI positions through an electro-hydraulic servo has its coil wiring and position feedback landed somewhere physical, and that somewhere is the TSVO servo terminal board. The IS200TSVOH1A — this unit carries the full string IS200TSVOH1AAA — terminates the servo loops for two valves and hands their signals to the servo I/O electronics. It is offered in used condition, cleaned and tested, with the warranty terms shown in the table at the end of this page.

Where the TSVO Board Fits in the Mark VI Servo Loop

GE's Mark VI documentation describes the Servo Terminal Board (TSVO) as the interface to two electro-hydraulic servo valves that actuate steam or fuel valves, with valve position measured by LVDTs wired to the same board. Two cables connect the board to the VSVO servo I/O processor — one to the J5 plug on the front of the VSVO, the other to the J3/J4 connectors on the VME rack. In simplex systems the signals ride the JR1 connector; in TMR systems they are distributed through JR1, JS1, and JT1 so that each of the <R>, <S>, and <T> channels sees the loop. Plugs JD1 and JD2 accept an external trip from the protection module, putting an independent shutdown path right at the valve interface.

Diagnose the Servo Loop Before Condemning the Board

Servo loop alarms implicate five things before the terminal board: the valve, the LVDTs, the field wiring, the cables, and the servo processor. A practical order of attack:

• Servo current out of limits or valve non-responsive: measure servo coil resistance right at the TSVO terminals and compare against the valve datasheet. A contaminated or sticking servo valve produces electrical-looking symptoms while being a hydraulic problem.
• Position (regulator) feedback out of limits: check LVDT excitation and signal wiring for opens, shorts, and swapped pairs — LVDT and wiring faults are far more common than terminal board faults.
• Loop trouble on one channel only: reseat the J5 and J3/J4 cabling and evaluate the VSVO card before the board; interconnect failures track to connectors more often than to etched copper.
• Fault stays on the position after processor and cables are exonerated: now the TSVO — including its ID chip, which the system monitors and flags on failure — becomes a legitimate suspect worth replacing.

IS200TSVOH1A: Group and Revision Explained

The number parses as IS200 (Speedtronic board series) + TSVO (Servo Terminal Board) + H1A (hardware group and version), with AA appended as the production revision to give IS200TSVOH1AAA. Both H1A and H1B boards circulate in the field; GE's public literature does not spell out the difference between the groups, so we advise matching the group letter on your existing label rather than mixing them. The general anatomy of these numbers is covered in our GE Speedtronic Part Number Decoder.

VSVO, PSVO, and Other Related Hardware

In the classic Mark VI rack, the mating electronics is the VSVO servo processor. In Mark VIe systems GE's IS220PSVO Servo Control I/O pack performs that role instead: it is documented as the electrical interface connecting a TSVO terminal board to one or two I/O Ethernet networks while running two servo valve position loops — and it must be manually reconfigured whenever the terminal board beneath it is changed, a step worth writing into any swap procedure. Find surrounding hardware in GE Mark VI IS200 Boards and the multi-generation catalog in GE Speedtronic Turbine Control Boards; for the DS200-to-IS200 story across platforms, see Mark V vs Mark VI: DS200 to IS200.

Quote Checklist for the IS200TSVOH1A

• Full part number with revision — here IS200TSVOH1AAA — exactly as the label shows
• A label photo whenever possible
• Turbine model, and whether the loop runs from a VSVO card or a PSVO pack
• Simplex or TMR configuration
• Quantity and the urgency of the requirement

Fast Quotes, Worldwide Delivery

Press Request a Quote with those details and you will hear back within 24 hours. We deliver worldwide on DDP terms, accept purchase orders, and package boards in ESD-safe materials for transit. This unit's condition and warranty are recorded in the table below.

General Information about the Product
Part Number	IS200TSVOH1A Mark VI IS200
Description	IS200TSVOH1A By GE IS200TSVOH1AAA Mark VI Servo Termination Board
Condition	used Cleaned and Tested. With 1 Year Warranty.