You are holding a GE Speedtronic board, or staring at an empty slot, and you need one answer before anything else: which Mark generation is this? Get it right and the correct spare is a short conversation. Get it wrong and you order a card that will never seat in your panel. The good news is that GE encodes the generation in the first characters of the part number, and the panel around the board confirms it. This guide shows you how to identify a Mark IV, V, VI, or VIe board fast — by prefix, and by the system it lives in.
This is the field-identification companion to our GE Speedtronic part number decoder; if you already have a clean part number, that guide breaks down every segment.
The prefix tells you the generation
The first block of characters on a Speedtronic board is the single most useful thing to know. Match it here, then browse the right shelf.
| Prefix | Speedtronic generation | Browse |
|---|---|---|
| IC3600 / IC3606 | Mark I and Mark II — early analog and discrete-logic cards | Mark I-II cards |
| DS3800 / DS3820 | Mark IV — early microprocessor control | Mark IV boards |
| DS200 | Mark V — triple-redundant (TMR) control | Mark V boards |
| IS200 / IS210 / IS215 / IS220 | Mark VI — VME-based control | Mark VI boards |
| IS400 / IS420 | Mark VIe and VIeS — current Ethernet (IONet) platform | Mark VIe boards |
Browse everything in one place in our GE Speedtronic Turbine Control Boards hub.
Confirm it by the system the board lives in
The prefix is definitive, but if a label is worn or you are working from a photo of the panel, the hardware architecture confirms the generation at a glance:
- Mark IV (DS3800): a card-frame of plug-in DS3800 boards, typically 1980s to early-1990s vintage. Analog termination, discrete cards, and a distinctive older cardrack. This is the generation most often being retired today.
- Mark V (DS200): DS200 boards arranged in the classic triple-redundant control scheme — the R, S, and T control cores plus a protective <P> core and common <C>/<Q> sections. If you see three matching control sections voting together, you are looking at Mark V. Our Mark V DS200 board guide explains the TCQA, TCEA, TCDA, TCRA and related cards and the R/S/T cores in detail.
- Mark VI (IS200): IS200-series boards seated in a VME rack, coordinated by a VCMI communication card. Available in simplex and TMR builds. See Mark V vs Mark VI for what changes at this transition.
- Mark VIe (IS420): a distributed design — small I/O packs mounted on terminal boards, tied together by an IONet Ethernet network to IS420 controllers. Per GE, Mark VIe supports simplex, dual, and dedicated triple-modular-redundant (TMR) configurations, so redundancy is a build option rather than a fixed trait.
The IS200 overlap — read the controller, not just an I/O pack
One nuance trips up buyers: IS200- and IS220-prefixed I/O packs appear in both Mark VI and Mark VIe systems. So a lone IS220 pack does not by itself tell you which of the two generations you have. The cleanest generational signal is the controller: a DS200 board is Mark V, a VME controller card is Mark VI, and an IS420 controller (with IONet Ethernet ports) is Mark VIe. When in doubt, identify the controller and the network — VME backplane versus IONet Ethernet — before you commit.
What the rest of the number changes
Once the prefix places the generation, the remaining characters identify the exact board. Take DS200TCQAG1BED:
- DS200 — the family (Mark V).
- TCQA — the functional acronym: what the board actually does.
- G1 — the group / style code. The letter that follows also signals the protective conformal-coating grade (a heavier-coating style is used in harsher environments).
- BED — the revision tail; each added letter tracks a functional revision of the board.
That revision tail is where ordering mistakes happen. Suppliers list the same board under a short number and a long number — for example DS200CSSAG1A and DS200CSSAG1AAA. The short form is the base catalogue number; the long form carries the specific revision letters. A later revision will usually drop into a slot that held an earlier one, but the reverse is not guaranteed and firmware or jumper expectations can differ. The full breakdown, including the G1A-versus-G1AAA question, is in the part number decoder.
Where to find the number on the board
On DS200 and IS200 cards the part number is silkscreened on the PCB, usually near an edge, and repeated on a paper or foil label. On older IC3600 and IC3606 cards it is often stamped on the card edge or the ejector tab. Read the number off the board itself, not the slot label in the cabinet — cabinet labels record what was originally installed, not necessarily what someone fitted during the last outage. If the silkscreen is unreadable, photograph the board; the component and connector layout is usually enough for us to identify the family.
What to send when you request a quote
- The full part number, revision tail included — DS200TCQAG1BED, not just "TCQA."
- The Mark generation and unit, and for Mark VI/VIe whether the panel is simplex or TMR.
- Which core or slot the board sits in — R, S, T, P or C on Mark V; the rack and slot on Mark VI.
- Condition you will accept — new surplus, open box, or tested used; on long-obsolete boards, new-in-box may not exist.
- Whether you can accept a superseding revision — this often turns a long hunt into a same-week shipment.
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