DS200TCDAH1BHD: Function and Placement

If you're chasing a contact-input or relay-output fault on a Speedtronic Mark V panel, the board responsible is the TCDA, and this listing is an H1-group DS200TCDAH1BHD unit. The card reads field contacts – limit switches, permissives, general status points – into the turbine control logic and drives relay outputs to contactors, solenoids, and annunciator circuits. Each terminal's role is defined by software configuration, not by the physical card.

The TCDA is mounted in one of the Mark V's control processor cores – <R>, <S>, or <T> in a TMR panel, or the single core in a Simplex panel – and is also documented as part of the card set in the <C> communication core on many systems. It works with a companion relay board (TCRA) and I/O cards such as TCQA, TCQE, and TCEA over the panel's IONET.

Diagnose Before You Commit to a Replacement

Since this unit ships new-surplus and factory-packaged, it's likely destined for a spares cabinet rather than an emergency same-day swap – which is exactly when it pays to build the correct diagnostic checklist for next time, rather than assuming any future TCDA alarm means this exact card has failed. Field-documented Mark V cases show these non-card causes behind classic TCDA symptoms (continuous I/O state cycling, repeated card-lost alarms):

• IONET termination resistors reversed. Termination should be IN at the TCDA and OUT on every TCEA card in the loop; one TCEA wired backwards reproduces the exact fault of a bad TCDA.
• A weak TCPS power supply feeding the core, rather than the TCDA card itself.
• Ripple or spikes on the DC control bus, from a battery charger or from de-energizing unsuppressed DC coils nearby.
• A firmware/PROM revision gap, which GE has resolved in some cases with a PROM upgrade rather than a hardware change.
• Loose card seating or a corroded connector pin.

It also helps to separate the TCDA from its relay-output partner, TCRA. TCRA relies on electromechanical relays that wear with switching cycles; the TCDA is solid-state and doesn't fail the same way. If the actual symptom is a relay output that won't energize, check TCRA first. On service life: there's no fixed age at which a TCDA needs replacing. Many stay in service eight-plus years, and general Mark V experience places mean time between failures in the low hundreds of thousands of hours, with cabinet heat, humidity, dust, and voltage transients being the more common real drivers of failure – which is also why keeping a tested spare like this one on the shelf, rather than waiting for a failure to source one cold, is common practice for critical units.

What H1BHD Tells You

DS200 is the Mark V-era series prefix, TCDA is the Digital I/O acronym, H1 is the product grouping, and BHD encodes this unit's functional and artwork revision levels. H1 and G1 are separate TCDA hardware groupings, not simply different ages of the same board – confirm which one your system calls for before ordering, and always match the complete suffix rather than just the base TCDA number.

Related Boards and Longer-Term Alternatives

TCDA is usually discussed alongside TCRA, TCQA, TCQE, TCEA, STCA, and UCPB. If your facility is weighing a platform change, GE's Mark VI system replaced the DS200 series with IS200-series boards under a different I/O architecture; see our Mark V vs Mark VI: DS200 to IS200 guide for the general mapping. For the logic behind GE's part numbers, see the GE Speedtronic Part Number Decoder, and for how TCDA fits among other DS200 boards, see GE Mark V DS200 Boards Explained.

What to Send With Your Quote Request

• Full part number and suffix, e.g., DS200TCDAH1BHD
• A photo of the label from your existing card, for comparison
• Turbine model and Mark V configuration (Simplex or TMR)
• Quantity
• Whether this is for stock/spares or an active outage

Request a Quote

This DS200TCDAH1BHD is new-surplus, factory-packaged stock with a 1-year warranty (see below). We don't publish prices online because Mark V board quotes depend on exact revision availability – submit a Request a Quote and our team will respond within 24 hours. We ship worldwide DDP, accept purchase orders, and support both spares planning and urgent turbine-down orders.

General Information about the Product
Part Number	DS200TCDAH1B Mark V DS200
Description	GE DS200TCDAH1B DS200TCDAH1BHD Digital I/O Board Mark V NEW
Condition	newSurplusFactoryPackage Original Factory Packaged. With 1 Year Warranty.