IC3600LRDH1B1D relay driver card: function and placement

Inside a GE Speedtronic Mark I / Mark II panel, the IC3600LRDH1B1D is the card that turns control decisions into physical action. As a member of the IC3600LRD relay-driver group, it accepts low-level commands from the turbine control logic and switches the output relays that drive the machine's solenoids, valves, ignition, contactors and alarm circuits. Without a healthy relay driver, the logic can call for an action all day and nothing moves in the field.

This is the LRDH variant at revision 1B1D. It is a discrete through-hole board that plugs into the control rack on an edge connector, with an individual transistor output behind each relay channel. That per-channel design is the key to efficient troubleshooting, because it lets you separate a single failed output from a fault affecting the whole card.

Separate a board fault from a field fault

On a relay driver, the most expensive mistake is treating a field problem as a board problem. The device that will not operate sits downstream of a long chain — logic, driver, relay, wiring, load — and any link can be the cause. Before you commit a spare:

• Start at the load and work back. Confirm the solenoid, valve or contactor and its wiring are intact. A shorted or open field device fails in ways that look identical to a dead driver channel.
• Check the relay coil and contacts. An interposing relay with an open coil or welded contacts will not obey the driver; test it directly rather than assuming the card.
• Verify command and output. Confirm the logic command reaches the channel input and that the transistor output switches in response. Command present, output switching, device still dead — look outward, not at the card.
• Reseat and clean the edge connector. Edge-finger oxidation and a loose rack seat cause intermittent, movement-sensitive faults that imitate a failing board on any IC3600 card.

Only when the load, the relay, the wiring and the command all check out is the LRDH1B1D itself the prime suspect.

What the IC3600LRDH1B1D revision code tells you

Read the number in blocks: IC3600 (Mark I / Mark II card series), LRD (relay-driver group), H (the specific driver variant) and 1B1D (the revision and dash detail). The 1B1D tail is what separates this card from an otherwise similar LRDH such as the 1A revision. Because revisions can change component values or channel arrangements, order against the full string rather than the base LRDH. Our GE Speedtronic Part Number Decoder shows how each block is interpreted.

Matching the right LRDH variant

The LRDH1B1D shares its slot family with the 1A revision and with the other relay drivers of the group (LRDC, LRDD, LRDJ), alongside the IC3600SIX interface and selector cards. Confirm which revision your panel was built with before ordering, since the wrong LRDH revision may fit the slot yet behave differently. You can compare options in our GE Mark I-II IC3600 Cards collection and the wider selection in GE Speedtronic Turbine Control Boards. This is Mark I-II hardware only: it does not interchange with the relay modules of later Speedtronic generations, and as a pre-TMR design it is a single-channel driver, not a voted R/S/T output.

Send these details with your quote

So we match the exact revision, include:

• The full part number with suffix as printed, for example IC3600LRDH1B1D.
• A photo of the card label and, if possible, the component side.
• Turbine model and Speedtronic generation (Mark I or Mark II).
• Quantity and how soon you need it.

Request a quote for this IC3600LRDH1B1D

This IC3600LRDH1B1D is a used card, cleaned and tested. Click Request a Quote for a reply within 24 hours. We ship worldwide DDP, accept purchase orders from qualified organizations, and can confirm the correct LRDH revision for your panel if you are unsure.

General Information about the Product
Part Number	IC3600LRDH1B1D Mark I-II IC3600
Description	IC3600LRDH1B1D By GE Speedtronic IC3600LRDH Relay Driver Card
Condition	used Clean and Tested With 1 Year Warranty.