New-Surplus DS3800HLIA1B1D Logic Input Board

This DS3800HLIA1B1D is offered as new surplus in factory packaging — a good fit when you want a shelf spare for the Mark IV logic input function rather than a repaired pull. Functionally it is the same GE Speedtronic DS3800 card described elsewhere as a logic input, High Voltage Logic Input Isolator, or Logic Input Auxiliary board, in the 1B1D group. Buying it as an unused spare is about protecting future availability of an obsolete part, since the Mark IV series has long been out of production.

What a Mark IV Logic Input Card Actually Does

The HLIA accepts high-voltage discrete inputs — the open or closed condition of field contacts, permissives, and switches — and converts them into isolated logic states the control can safely read. The isolation is the point: it blocks transients, induced noise, and ground disturbances on the field wiring from crossing into the low-voltage processor sections. In a Speedtronic Mark IV those sections are the triple-redundant <R>, <S>, and <T> controllers plus the <C> communications section, which vote two-out-of-three on the resulting logic. The card racks into the panel through a modular connector and is retained by levers that keep the connector fully engaged.

Commissioning a Spare: Check These Before You Rely on It

A new-surplus board still deserves a few checks before it goes on the shelf or into service:

• Verify the exact group code. Confirm the label reads DS3800HLIA1B1D and compare the revision against the card you intend to replace, so the spare is a true match when you need it.
• Inspect for storage effects. Look the board over for bent connector pins or handling damage before installation.
• Plan the swap with power off. When the time comes, de-energize the panel, release the levers, seat the new card firmly in the modular connector, and confirm the amber LED lights (powered and self-test passed) with the red indicators showing activity.
• Keep the field side in mind. If an input still misreads after fitting a known-good new card, the field contact or wiring is the more likely cause.

Group Suffix, Revision, and Interchangeability

In the DS3800 scheme, DS3800 is the Mark IV series, HLIA is the logic-input function, and 1B1D is the group code identifying this precise version and revision. Different group codes within the HLIA family can reflect different hardware or firmware, so a spare is only truly interchangeable when its code matches the installed card. Because GE does not publish a public key to every character, the safest approach is exact-code matching, backed by a photo of the board. Our GE Speedtronic Part Number Decoder covers the convention.

Related GE Speedtronic Control Boards

Browse the wider DS3800 set in our GE Mark IV DS3800 Boards collection, or the full GE Speedtronic Turbine Control Boards range across Speedtronic generations.

Request Your DS3800HLIA1B1D Quote

Tell us the full part number with the 1B1D suffix, the revision you need to match, and include a photo of your existing board label along with the turbine frame, Mark generation, quantity, and urgency. We confirm the correct card and availability, respond within 24 hours, ship worldwide DDP, and accept purchase orders.