IS200TTURH1BAA: A Terminal Board, Not the VME Card

The IS200TTURH1BAA is GE's Turbine Termination Terminal Board (TTUR) for the Mark VI Speedtronic system — the physical panel where turbine-side field wiring actually lands. GE's own SPEEDTRONIC Mark VI documentation is specific about this point: the TTUR terminal board works together with a separate VME card, VTUR, which sits inside the R/S/T Control Module and runs the actual control logic. The TTUR connects to that card by cable, through six D-type connectors labeled JR1, JR5 (R channel), JS1, JS5 (S channel), and JT1, JT5 (T channel). If you're troubleshooting a synchronizing or speed-sensing problem, keeping that terminal-board-versus-VME-card distinction straight will save you from chasing the wrong part.

Functionally, the TTUR handles the turbine's speed and synchronizing inputs: passive magnetic pickups sensing a toothed wheel for turbine speed, generator and bus voltage signals from potential transformers for synchronizing, and shaft voltage/current monitoring. It also drives the generator breaker coil (52G) at a nominal 125 V DC through a set of synchronizing permissive relays — K25, K25P, and K25A — all of which need to be satisfied before the breaker will close. Field wiring for magnetic pickups, shaft pickups, potential transformers, and breaker relays connects to two removable terminal blocks, TB1 and TB2, each with 24 screw terminals rated for wire up to #12 AWG, with a shield termination strip to chassis ground beside each block. Jumpers JP1 and JP2 select simplex or TMR operation for the K25/K25P relay drivers.

What to Check Before You Replace This Board

A synchronizing failure or a speed-related alarm is often not a TTUR hardware failure. Work through this first:

• Synchronizing won't complete or the breaker won't close: check the external synch check relay wiring, the 52G/a breaker auxiliary feedback contact, the PT wiring and fuses feeding the board, and confirm the JP1/JP2 jumpers are set correctly for your simplex or TMR configuration.
• Erratic or false overspeed readings: this is very often a magnetic speed pickup that has drifted in its air gap, a loose or damaged cable run, or electrical noise between the pickup and TB1/TB2 — not a board failure. In TMR systems, a single bad pickup or wiring run usually shows up as a voting/disagreement alarm between R, S, and T rather than an outright board fault.
• Shaft voltage or shaft current alarms: these typically point to a grounding brush or bearing insulation problem on the actual turbine-generator shaft train. The TTUR (working with VTUR) only monitors that condition to protect the bearings from electrical discharge damage — replacing the terminal board will not fix a mechanical grounding issue.
• Check terminals and connectors before ordering a new board. A loose screw terminal on TB1/TB2 or a partially seated JR/JS/JT cable connector is a far more common failure mode than a dead terminal board.

Reading the IS200TTURH1BAA Part Number

IS200 is the platform prefix, TTUR is the function code, and H1BAA is the group and revision — H1B for the group/generation, AA for this specific hardware revision. Order against the complete string; GE's H1B and H1C groups (both stocked in this collection) share the same basic TTUR function but are not necessarily interchangeable revision-for-revision. Our GE Speedtronic Part Number Decoder covers how to read a full IS200 part number off a worn or partial label.

Related Boards

The TTUR's direct companion is the VTUR VME card inside the Control Module. The generator breaker trip circuit also involves the TRPG terminal board (driven by VTUR) and, in the Backup Protection Module, the TREG terminal board (driven by the VPRO card) — both are part of the same synchronizing and protection scheme. If you're also supporting Mark V equipment, see our Mark V vs Mark VI: DS200 to IS200 guide and GE Mark V DS200 Boards Explained article. Browse the rest of the family in our GE Mark VI IS200 Boards collection or the wider GE Speedtronic Turbine Control Boards collection.

What to Include in Your Quote Request

• Full part number with suffix: IS200TTURH1BAA
• Revision from the label
• Photo of the ID label
• Turbine/generator model and unit ID
• Planned outage or urgent need
• Quantity

Request a Quote

This IS200TTURH1BAA is listed in used condition, cleaned and tested, with a 1-year warranty (see table below). We quote every order directly rather than publishing prices — submit a Request a Quote and expect a reply within 24 hours. We ship worldwide DDP, accept purchase orders, and support both planned outages and urgent breakdown needs.

General Information about the Product
Part Number	IS200TTURH1B Mark VI IS200
Description	GE General Electric IS200TTURH1B IS200TTURH1BAA Termination PC Board Mark VI
Condition	used Cleaned and Tested. With 1 Year Warranty.