The Mark V's Relay Output Card, Explained

Every digital output the Mark V sends to the field passes through a relay, and on a Speedtronic panel those relays live on the DS200TCRA. The board holds up to thirty electromechanical plug-in relays, numbered K1 through K30, and switches the solenoids, contactors and permissive contacts that the turbine control logic calls for. It is one of the more frequently serviced boards in a Mark V lineup for a simple reason: relays are mechanical, and mechanical parts wear.

Physically, the TCRA sits in the digital I/O section rather than in the <R>, <S>, <T> or <C> control cores. A digital I/O core normally holds two TCRA boards paired with a TCDA digital I/O board, which is the card that actually commands the relay coils. Contacts are wired out to the DTBC and DTBD terminal boards. Whether a given output is a dry contact or a wetted solenoid supply is set by jumpers on those terminal boards, not on the TCRA, so the relay card itself is purely hardware with nothing to configure.

Is the TCRA Actually at Fault?

Before you buy a replacement, make sure the relay board is really the problem — on the Mark V it frequently is not. The TCDA keeps a voltage on one leg of each relay coil and energizes the relay by pulling the other leg down to common. That means a relay that never picks up can just as easily be a bad driver channel on the TCDA, or a poorly seated ribbon cable between the TCDA and TCRA, as a failed relay.

A quick way to divide the problem:

• Watch the output at the TCDA. If the command never arrives there, look upstream — the relay board is innocent.
• If the command is present but the contact stays open, suspect the individual relay, the TCRA, or the interconnect ribbon; a "plug disconnected" alarm names that ribbon directly.
• Inspect the field circuit. A solenoid that has shorted on a 125 VDC output can cook a relay and burn the terminal-board tracks, and it will take out a new board too if you fit one before the short is cleared.

In practice the plug-in relays are the wear item and are often replaced individually, while the board as a whole usually survives unless it has seen an overvoltage surge or a battery ground. Sorting that out first is what keeps you from swapping a healthy card.

Group and Revision on a DS200TCRA

The label on this board reads DS200TCRAG1A, with the full number DS200TCRAG1AAA. DS200 identifies the Mark V board series, TCRA is the relay-output function, G1 is the build group, and the letters that follow record the revision. GE also built the TCRA as a group 2 card (DS200TCRAG2A), and a different group is not automatically a drop-in, so order to the group and revision your panel was commissioned with unless a supersession has been confirmed. The GE Speedtronic Part Number Decoder explains the fields; read the number from the board itself, since slot labels are not always reliable.

Related TC-Series Cards and the Mark VI Path

Around the TCRA you will find the rest of the Mark V TC family: the TCDA that drives it, the TCQA analog I/O, and the TCPS supply that powers the core. The GE Mark V DS200 Boards Explained guide shows how they fit together, and our GE Speedtronic Turbine Control Boards collection covers the wider catalog. When a fleet is moving forward a generation, Mark V vs Mark VI: DS200 to IS200 outlines how the DS200 I/O was re-architected as IS200.

Details That Help Us Quote Your Board

• The complete part number with its revision suffix (DS200TCRAG1AAA).
• A photograph of the board's label and silkscreen.
• Turbine model, and whether the control is a Simplex or TMR Mark V.
• The core the board serves, plus the revisions in any paired cores.
• How many you need and your required timing.

Request Your Quote

This DS200TCRAG1AAA is new surplus in the original factory packaging, carrying a one-year warranty — a card that has never been through a turbine-cabinet thermal cycle. Tell us the details above and we will come back within 24 hours with availability and lead time. We deliver worldwide DDP and accept purchase orders; click Request a Quote to begin.