Extended Analog I/O for the Mark V Control Cores

Not every Speedtronic Mark V panel carries a TCQB — but the ones that do depend on it for shaft vibration, position, and valve feedback measurement. The DS200TCQBG1A, supplied here as new surplus revision DS200TCQBG1AFB in original factory packaging, is GE's RST Extended Analog I/O board. It installs at location 3 of the control cores — one board in <R> for a Simplex panel, one each in <R>, <S>, and <T> for TMR — and extends the analog capacity of the primary TCQA analog I/O card it works alongside. GE's Mark V application documentation (GEH-6195) lists the TCQB's function groups as proximitor inputs, LVDT/LVDR inputs, two regulator milliamp outputs, and LM vibration inputs, and notes its use on steam turbine Simplex panels and on TMR applications where proximity probes are required.

Physically the board carries a programmable logic device with socketed EPROM firmware modules, a bank of configuration jumpers, a 50-pin connector, and a single OK LED positioned to be visible from the side of the card rack. The first three proximitor input points (PRX01–PRX03) can alternatively accept accelerometer inputs; the selection is made with hardware jumpers on the board plus the matching I/O configuration constants in software.

Is the TCQB Actually Your Problem?

Analog channel trouble invites board-swapping, and the TCQB is rarely the right first suspect. Work the loop from the outside in:

• Sensor and wiring first. A dead or drifting vibration or position channel usually starts at the probe, extension cable, or termination — not on the card. On TMR panels, compare the same input across <R>, <S>, and <T>: three cores disagreeing with reality in unison points at the field side, because three simultaneous board failures do not happen.
• Jumpers after any sensor change. If a proximitor was swapped for an accelerometer (or vice versa) on inputs 1–3, wrong jumper positions produce exactly the "bad board" signature. Verify positions against the application documentation before ordering hardware.
• Power and cables inside the core. A dark OK LED with the core otherwise alive means checking card seating and the ribbon cables from the core's TCPS supply — a public Mark V field case traced cards dropping off the I/O status list to one loose power ribbon, and ended by replacing the TCPS, not the analog cards.
• Firmware seating. Socketed EPROMs with decades of thermal cycles develop pin corrosion; intermittent configuration and diagnostic errors sometimes clear with a careful reseat.
• Right sibling? Diagnostic alarms name the card they implicate. TCQA is the primary analog card and TCQC the analog expander; confirm the alarm text references TCQB before quoting one.

Understanding DS200TCQBG1AFB

DS200 is the GE board series; TCQB the extended analog function; G1A means Group 1 at base functional revision A; FB closes the string with the later revision letters — read by the trade as a subsequent functional revision F with artwork revision B. Group and base revision (G1A versus G1B versus G2A) are the compatibility boundaries to respect; we stock the G1B and G2A builds as well, so quote your label exactly. One planning note for replacement hardware: TCQB boards are supplied without application firmware installed — the EPROM modules from your existing board carry your unit's code and transfer to the replacement, or a matching PROM set from the DS200TCQBF1 series supplies it. Full lettering logic: GE Speedtronic Part Number Decoder.

The TCQA / TCQB / TCQC Analog Family

Mark V analog I/O in the control cores is a three-card family: TCQA carries the primary analog I/O, TCQB extends it, and TCQC handles overflow analog capacity — all three are documented on this site and stocked in the GE Mark V DS200 Boards collection. For how the cores and card locations fit together, see GE Mark V DS200 Boards Explained; for what became of these functions on the Mark VI platform, see Mark V vs Mark VI: DS200 to IS200.

Information That Speeds Up Your Quote

• Complete part number from the label — DS200TCQBG1AFB — including every revision letter
• A label photo, which settles group and revision questions immediately
• Panel type (Simplex or TMR) and turbine application (steam or gas), since board count differs
• Your firmware plan: transferring your existing EPROMs, or sourcing a PROM set alongside the board
• Quantity, urgency, and destination country

New Surplus Availability and Terms

This DS200TCQBG1AFB is new surplus in original factory packaging with the warranty stated in the table below. Use Request a Quote and our team will reply within 24 hours with availability and lead time. Worldwide delivery is DDP — landed at your plant with duties paid — and purchase orders are accepted.

General Information about the Product
Part Number	DS200TCQBG1A Mark V DS200
Description	GE DS200TCQBG1A DS200TCQBG1AFB RST Extended Analog I/O Board Mark V
Condition	newSurplusFactoryPackage Original Factory Packaged. With 1 Year Warranty.