Owners of ageing turbine fleets ask the same question in two forms: can I put an IS200 card in my Mark V? and do I have to migrate? The short answers are no and not yet. The longer answer is worth understanding, because it determines how you buy spares for the next decade.
Browse: Mark V DS200 boards · Mark VI IS200 boards · all Speedtronic generations
They are different machines, not different revisions
Mark V (DS200) and Mark VI (IS200) are separate control system generations. Mark VI is built around a VME backplane, and its cards are VME cards. Mark V cards are not. A IS200PSCDG1A Mark VI board and a DS200CSSAG1A Mark V board share a manufacturer and a product name and essentially nothing else that matters mechanically or electrically.
There is no adapter, no carrier, no firmware trick. If someone offers to sell you one as a substitute for the other, walk away.
What actually changed
The controller
Mark VI centralises control on a UCVx-family controller — for example the IS215UCVEH2AAE, a single-slot VME board. External data reaches it through the VCMI communications board. Depending on the system, that data arrives either as process I/O (simplex) or as voted I/O (TMR).
Redundancy became a choice
This is the most consequential difference. Mark V was designed as a triple modular redundant system. Mark VI was designed to offer both TMR and simplex control. That means two Mark VI panels can be architecturally different from each other in a way two Mark V panels are not — and it means the board you need depends on which one you have.
The VCMI board makes this concrete: VCMI cards come in Simplex and TMR versions, and they are not the same part. The simplex card has one IONet port; the TMR version has three. Counting the IONet ports on the card in your rack is the fastest way to tell which architecture you are dealing with before you order.
Protection moved onto dedicated cards
On Mark VI, VTUR handles the turbine protection functions: it measures turbine speed to generate the primary overspeed trip, controls the three primary overspeed trip relays on the TRPx terminal board, and monitors eight flame detectors. VPRO is the companion protection module. If you are sourcing anything in the protection path, revision and architecture matching is not optional.
I/O cards
Mark VI analog I/O is handled by VME cards such as VAIC (analog input) and VAOC (analog output), rather than the Mark V TCQA / TCQC family. The IS200STCIH6A DIN-rail contact terminal board is an example of the Mark VI terminal-board approach.
The prefix trap: IS200 vs IS210 vs IS215
Within Mark VI you will see IS200, IS210, IS215 and IS220 numbers. These are all Mark VI-era numbers and they are frequently cross-referenced against each other by suppliers. Some boards genuinely appear under more than one prefix. Do not assume a prefix difference means a different board, and do not assume it means the same board. Quote the full number and confirm.
Our IS210MVRCH1A I/O interface board is a good example of an IS210-prefixed Mark VI card. And note that IS400 / IS420 numbers are not Mark VI at all — they belong to the newer Mark VIe and VIeS platform.
Should you migrate?
That is a capital decision, not a parts decision, and it depends on your outage windows, your risk tolerance and what your insurer and regulator expect. What we can tell you is the supply picture, because we live in it:
- Mark IV (DS3800) spares still move. The market is surplus and refurbished, not new production. Boards like the DS3800DGPA programming auxiliary and the DS3800HACB Series Six receiver board are findable, but lead times are unpredictable.
- Mark V (DS200) is the deepest surplus pool right now. If you run Mark V, the pragmatic strategy is to buy your critical spares while the pool is deep rather than when the board fails.
- Mark VI (IS200) is still widely supported and is where most fleets sit.
- Mark I / II (IC3600, IC3606) are genuinely scarce. If you are still running one of these, an on-shelf spare set is not a luxury. Even the service items — like the IC3606DEXB extender board used to test cards outside the rack, or the IC3600SOTE over-temperature card — are getting hard to find.
The honest framing: migration is driven by risk, not by whether a part exists. Parts exist for all of these systems today. The question is how long you want to depend on a surplus market for a machine you cannot afford to have down.
What to tell us when you ask for a quote
- Which Mark generation, and for Mark VI, whether the panel is TMR or simplex — count the IONet ports on the VCMI if you are unsure.
- The full part number with the revision tail, read off the board itself.
- The rack and slot, or on Mark V the core.
- Whether you can accept a superseding revision or an alternate prefix (IS200 vs IS210, for instance). This is frequently what makes a part findable.
- Whether this is a breakdown or a shelf spare. It changes what we go looking for.
We reply within 24 hours, ship worldwide DDP, and accept purchase orders.
Related: GE Speedtronic part number decoder and GE Mark V DS200 boards explained.