DS3800DFPH1D1B (Open Box) for GE Mark IV

This listing is an open-box DS3800DFPH1D1B: new-surplus hardware supplied without its original sealed carton, cleaned and tested, and carrying a one-year warranty. Electrically it is the same GE Speedtronic Mark IV control board assembly as a boxed 1D1B; the difference is packaging and handling history, not the card itself.

What Open Box Means Here

An open-box unit has left its factory packaging at some point but has not been placed into turbine service. Before listing, the board is cleaned and functionally tested so you can install it with confidence. If you need certified new-in-box stock for a documentation trail, tell us and we will quote a factory-packaged 1D1B instead — otherwise this open-box card is a cost-effective, tested option for the same group and revision.

Placement in the Speedtronic Mark IV Rack

The Mark IV is GE's first triple modular redundant (TMR) Speedtronic system, running three control processors — <R>, <S> and <T> — that vote two-out-of-three, plus a <C> communications processor that feeds the CRT operator interface. The DFPH board is one DS3800 card in that rack, connected to the rest through ribbon cables and backplane connectors. Because the DFPH code marks a defined position, confirm the exact function of your card against the unit's elementary and renewal-parts list; we avoid quoting pin assignments or voltages that are not verifiable on the board.

Before You Fit It: Localize the Real Fault

Open-box or not, the smart move is to prove the board you removed was actually bad. On Mark IV cabinets, check these first:

• DC supply. Confirm the DS3800 power-supply rails feeding the rack; a marginal supply mimics logic-card faults.
• Cable and seating. Reseat the card and inspect the ribbon and backplane connector for damage or contamination before replacing anything.
• Which core alarms. Identify whether <R>, <S> or <T> disagrees; the vote often names the fault location.
• Adjacent boards. A companion card in the signal path can generate an alarm that looks like a DFPH fault.
• Trim settings. Copy any calibration adjustments from the old board so the replacement reads correctly from the start.

The 1D1B Suffix and Why It Must Match

The number reads DS3800 (Mark IV family) + DFPH (function) + 1D1B (group and revision). The 1D group and its 1B revision must match your installed board, because different groups of the same card can differ in configuration or firmware. Keep the full suffix in every request; the GE Speedtronic Part Number Decoder explains how the codes are built and why they change between production runs.

Related DS3800 Boards to Consider

Alongside the DFPH, a Mark IV cabinet holds many other DS3800 cards — microprocessor, memory, communication and power-supply boards among them. See the GE Mark IV DS3800 Boards collection for the family, or the wider GE Speedtronic Turbine Control Boards range for other generations. Evaluating a longer-term migration? Mark V vs Mark VI: DS200 to IS200 compares the later Speedtronic platforms.

What We Need to Prepare Your Quote

• Full part number and suffix (DS3800DFPH1D1B);
• Board revision and label photo where available;
• Turbine model and Mark IV confirmation;
• Quantity, plus whether packaging (open-box vs factory-sealed) matters for your order.

Start Your Quote Request

This open-box DS3800DFPH1D1B is cleaned, tested and warranted for one year. Use Request a Quote for a reply within 24 hours. We ship worldwide DDP and accept purchase orders from qualified organizations; let us know if you require factory-sealed packaging and we will quote that alternative as well.