Structural Features:​ The board accepts an optional auxiliary board (DS3800DBPA). When this auxiliary is installed it gives the motherboard access to its six potentiometers and several PCB snap-in screw mounts. The auxiliary board installs on the right-hand side of the motherboard, rests on four nylon pins and is held in place by twenty-nine board-to-board connectors. The board is alignment-marked and marked “NGPA 6DA08” and “6BA05”. It has been drilled in all corners. Extractor clips are installed in the right-hand corners. The board has one amber LED and six red LEDs in line with seventeen (TP) test points. Built with five transistors, one potentiometer, and multiple integrated circuits including dual operational amplifiers. Multiple diodes, capacitors, and resistors (primarily ceramic metal film) populate the board. Capacitors include one 25v 50 μf (orange) capacitor.

Working Principle:​ The board accepts low-level analog inputs from field sensors and amplifies them into clean, high-level linear signals compatible with the system’s central logic processors. Its multi-channel operational amplifier configuration, combined with multi-turn precision trimming potentiometers, ensures accurate gain and offset adjustment.

Application Scenarios:​ Widely used in legacy Speedtronic Mark IV turbine control panels for gas or steam turbine management. It automates some routines, including start-up and shutdown, and is designed to keep the system from operating during unsafe or adverse conditions.

Supply Chain Note:​ The Mark IV system is completely obsolete. Choosing unverified or used marketplace components exposes instrumentation loops to severe drift and calibration errors that can lead to false turbine trips. A New Surplus board avoids component aging, dried-out capacitors, and faded trace paths inherent to refurbished items.