Description
Hardware & Electrical Specifications
‑ Manufacturer: GE General Electric ‑ Compatible System: Speedtronic Mark‑V Turbine Control, EX2000 Excitation System ‑ Functional Acronym: TBQC (RST Analog Termination Board) ‑ Signal Types Handled: • 4‑20 mA / 0‑20 mA analog current loop inputs from field transmitters (pressure, flow, temperature) • LVDT/R position feedback signals • Analog current outputs configurable for 20 mA maximum or 200 mA maximum via hardware jumpers ‑ Terminal Blocks: 2 screw‑type terminal blocks (TB1, TB2), 83 terminals per block, total 166 field‑wiring connection points ‑ Inter‑Board Connectors: 3 ×40‑pin, 3 ×34‑pin ribbon‑cable headers for connection to TCQA core boards ‑ On‑Board Jumpers: Total 15 configurable Berg‑style jumpers; key jumper groups include JBR, JFR, JBS/T, JFS/T, TEST. Jumpers select output‑current limit mode, signal routing and channel assignment. All jumper positions must be exactly duplicated during replacement ‑ Protection Circuitry: TVS diodes, clamping capacitors and transient‑suppression components for surge and noise protection on field signal lines ‑ Power Source: Receives operating bias power from TCQA boards through multi‑pin ribbon connectors; no independent external power supply ‑ PCB Finish: Conformal coated multilayer FR‑4 PCB ‑ Compatibility Restriction: Works only for Mark‑V / EX2000. Not mechanically or electrically compatible with Mark‑VI / Mark‑VIe control racks.
Environmental Specifications
‑ Operating Temperature: 0 °C ~ +60 °C ‑ Storage Temperature: −40 °C ~ +85 °C ‑ Relative Humidity: 5%‑95 % non‑condensing ‑ Installation Environment: Control cabinet interior, Pollution Degree 2 ‑ EMC: Designed for power‑plant cabinet EMI, motor‑noise and switching‑transient conditions
Mechanical Data
‑ Physical Dimension: 286 mm × 76 mm (11.25 inch ×3 inch) ‑ Mounting: Four‑corner screw mounting holes for direct cabinet back‑plate installation ‑ Weight: approx 0.32 kg
Core Functions
- Field‑signal termination: High‑density screw terminals terminate field wiring for 4‑20 mA transmitters and LVDT/R position sensors. Standard twisted‑shield field cables land on TB1 and TB2 terminal blocks.
- Transient surge protection: On‑board suppression components absorb lightning‑induction and field‑wiring fault transients, isolating and protecting the downstream TCQA controller electronics.
- Configurable signal routing: 15 hardware jumpers define channel routing, select analog‑output maximum current limit (20 mA / 200 mA mode), match field device hardware requirements.
- Signal cross‑connect between field and core controller: Multi‑pin ribbon‑cable headers pass analog milliamp and LVDT/R signals back‑and‑forth between TBQC and each core’s TCQA processing board.
- Test access: Dedicated TEST connector provides convenient test‑point access for field technicians for signal measurement during commissioning and troubleshooting.
Installation, Replacement & Critical Warnings
- Complete system power‑down and lock‑out procedure required before servicing. Non‑hot‑swappable. ESD wrist‑strap protection is mandatory when handling the PCB assembly.
- Before removing the original TBQC board, record every single jumper position. The replacement board must replicate jumper settings 100 %; incorrect jumper configuration causes wrong output‑current range, lost analog channels, or erroneous turbine‑process measurements.
- Secure all screw‑terminal connections to proper torque; loose field‑wiring terminals produce drifting, noisy analog readings. Tighten all 34‑pin and 40‑pin ribbon‑cable connectors.
- After power restoration, perform loop‑check verification: validate 4‑20 mA input values at HMI, verify analog‑output drive levels, and confirm LVDT/R position feedback readings.
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Common failure mode: Surge damage originating from field‑wiring faults can blow suppression components on TBQC, while leaving the downstream TCQA board unharmed. Always inspect TVS and capacitor components during repair assessment.





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