What a TCRA Relay Board Handles

On a Speedtronic Mark V, the DS200TCRA is where the control logic meets the field: a bank of up to thirty relays that switch solenoids and contacts on command. Each relay — K1 through K30 — is an electromechanical, plug-in device, and together they form the panel's contact-output layer for valves, ignition circuits, motor starters and status contacts. Because the relays physically make and break current, this is a board that sees real mechanical duty over a turbine's life.

It is worth being precise about where it lives. The TCRA is not a processor card in the <R>, <S>, <T> or <C> cores; it is part of the Mark V digital I/O, where a pair of TCRA boards is driven by a TCDA digital I/O board in the same core. The relay contacts terminate on the DTBC and DTBD boards, and the card carries no software — its behavior is fixed in hardware, with output type selected by terminal-board jumpers.

Rule Out the Driver and the Field Before Swapping

The most expensive mistake with a relay-output problem is replacing the TCRA when the fault is somewhere else in the chain. The Mark V drives each relay by holding one side of the coil at a fixed voltage on the TCDA and sinking the other side to common to pick it up. So an output that fails to operate can be caused by the TCDA driver, by the ribbon cable that links the TCDA to the TCRA, by the relay itself, or by a fault in the field — and only the last two involve this board.

Check these in order:

• Confirm the command actually reaches the TCDA. If it does not, the problem is upstream in the logic or communications, and no relay board will change that.
• If the command is there but nothing switches, look at the specific relay, the TCRA, and the ribbon connection; a disconnected-plug alarm points at the ribbon.
• Look hard at the field wiring. A shorted 125 VDC solenoid can destroy a relay and char the terminal board, and it will damage a replacement just as fast if the short is still present.

Field experience is consistent on this: the individual relays wear and are replaced far more often than the board fails outright, and a board-level failure usually traces back to a surge, a battery ground, or a downstream short. Diagnose to that level and you order the right part once.

Where the TCRA Sits Among the Mark V Boards

The relay board is one node in the Mark V I/O family. The TCDA digital I/O board is its driver, the DTBC and DTBD boards are its field terminations, the TCQA handles analog I/O, and the TCPS provides core power. Our GE Mark V DS200 Boards Explained guide maps the group, and the GE Mark V DS200 Boards collection lists current stock. For operators comparing generations, Mark V vs Mark VI: DS200 to IS200 covers how the same I/O roles carry over into the IS200 platform.

How the DS200TCRA Part Number Is Built

This board is a DS200TCRAG1A, full number DS200TCRAG1AAA. Read left to right, that is the DS200 Mark V series, the TCRA relay-output function, the G1 group, and a revision suffix (AAA). A separate group 2 version exists as DS200TCRAG2A; because the group can change form, fit or function details, match the group and revision your panel expects instead of assuming interchangeability. The GE Speedtronic Part Number Decoder covers each character, and the number should always be taken from the board's own silkscreen.

Information to Include in a Quote Request

• Full part number and revision suffix (DS200TCRAG1AAA) from the board label.
• A photo of the label and silkscreen so we can verify the exact build.
• Turbine model and Mark V architecture (Simplex or TMR).
• The serving core and the revisions in any partner cores.
• Quantity and urgency.

Get a Quote in 24 Hours

This DS200TCRAG1AAA is offered as new surplus, factory packaged and out of the box, with a one-year warranty. Send the details above through the Request a Quote button and we will reply within 24 hours with availability and lead time. Orders ship worldwide DDP, and purchase orders are welcome.