What the IC3600EPSD1C1B 28 V power supply card does

The IC3600EPSD1C1B belongs to the IC3600EPS power-supply group of GE's Speedtronic Mark I / Mark II turbine control — the earliest Speedtronic platform, assembled from discrete, plug-in analog cards. Its job is to provide and regulate a 28 V DC rail for the panel. In an early Speedtronic cabinet the 28 V rail is a workhorse supply behind relay coils, contact wetting and interface circuits, so when it sags or disappears the symptoms tend to spread across the panel rather than point to one obvious board.

The EPS group splits the supply across several cards instead of one sealed module. The EPSU primary supply control card and its EPSV pulse source manage the main switching stage; the EPSC inverter drive card drives that stage; and regulator cards such as the EPSS (which derives a regulated -12 V from the -50 V bus) and the EPSW handle other rails. The EPSD sits alongside them as the dedicated 28 V supply and regulator. Understanding that division of labor is what keeps you from replacing the wrong card.

Check the source rail before condemning a supply card

A 28 V card that reads low or dead is very often reporting a problem it did not cause. Before you order a replacement:

• Look for an external overload first. The 28 V rail typically feeds relay coils and field wiring. A shorted coil, a pinched wire or a stuck contactor can drag the rail down and make a perfectly good EPSD look faulty. Isolate the load and see whether the rail recovers.
• Verify the input bus. Confirm the upstream supply feeding the EPS group is present and in tolerance. If the input is missing, the fault is upstream at the source, fuses or wiring — not on this card.
• Reseat and clean the edge connector. As with every IC3600 card, corroded edge fingers or a loose rack seat cause intermittent 28 V behavior that imitates a failed regulator. Clean the edge and the rack connector and reseat before judging the board.
• Measure output against input. With the load isolated and the input confirmed, an output that is still wrong points to the card itself. Only at that point is the EPSD the likely culprit.

This sequence matters because a genuine 28 V card is a scarce legacy spare; you do not want to consume one chasing a shorted relay out in the field wiring.

How the EPSD part number breaks down

IC3600 marks the Mark I / Mark II Speedtronic card series; EPS is the power-supply group; the following D identifies this particular card type (the 28 V supply, as opposed to the C inverter drive or the S and W regulators); and 1C1B is the revision and dash detail. The dash characters are not decoration — a different revision can carry different jumpering or component values, so match the whole number rather than just the base. Our GE Speedtronic Part Number Decoder explains how these blocks fit together.

Where the 28 V card fits among the EPS regulators

The EPSD rarely lives alone. In the same rack you will usually find the EPSU/EPSV primary supply pair, the EPSC inverter drive, and the EPSS and EPSW regulator cards, all cooperating to produce the panel's family of DC rails. When you are chasing an intermittent supply fault, having a known-good example of each neighbor to substitute is invaluable. Browse the group in our GE Mark I-II IC3600 Cards collection, or the broader control range in GE Speedtronic Turbine Control Boards. Because Mark I-II is a pre-TMR generation, these supply cards are single-channel hardware and are not part of any R/S/T voting scheme.

Information that speeds up your quote

Send us the following so we can match the exact card:

• The complete part number and suffix as printed on the board, for example IC3600EPSD1C1B.
• A photograph of the card label and the board if you can.
• Your turbine model and whether the panel is Speedtronic Mark I or Mark II.
• How many you need and your required timeframe.

Request a quote on the IC3600EPSD1C1B

This IC3600EPSD1C1B is offered as new surplus, no box. Use Request a Quote and we will reply within 24 hours. Shipping is worldwide DDP, purchase orders are accepted from qualified organizations, and we are glad to help you line up the neighboring EPS cards if you are refreshing the whole supply.

General Information about the Product
Part Number	IC3600EPSD1C1B Mark I-II IC3600
Description	IC3600EPSD1C1B By GE Speedtronic IC3600EPSD 28 Volt Power Supply Card NSNB
Condition	newSurplusNoBox With 1 Year Warranty.