IC3600AOAJ1A: Keeping an Obsolete Speedtronic Amplifier Card Alive

The IC3600AOAJ1A is an amplifier board for GE's Mark I and Mark II Speedtronic, the original analog generation of GE turbine control. It sits in the AOA operational-amplifier family, carrying op-amp circuitry that amplifies and conditions the low-level signals the early Speedtronic uses to run its control and protection loops in hardware. This family has been out of production for many years, so for a plant still running Mark I-II equipment the practical question is not whether a board will eventually need replacing but whether a matched spare is on the shelf when it does. This listing is a new-surplus, no-box AOAJ1A held for exactly that purpose.

Physically it is a standard IC3600 board: through-hole analog construction with trim potentiometers, transistors, electrolytic and film capacitors and mixed carbon-composition and metal-film resistors, engaging the rack through a row of edge pins and marked with the GE logo and etched identification codes.

Rule Out the Rack and the Signal Source First

A spare is only useful if you install it for the right reason. Before you fit the new-surplus board, confirm the old amplifier is genuinely the fault, because several things imitate a failed AOA card:

• Calibration. The trim potentiometers set gain and offset for the loop. A reading that is high, low or drifting can be a trim that has moved rather than a dead board. Note too that a freshly fitted card must be calibrated to the loop under the OEM procedure before you trust its output.
• The rack supply. Op-amp stages need steady rails from the Mark I-II self-contained supply. Measure them; an unstable supply distorts the amplifier output and looks like a card fault.
• The edge connection. Pins and sockets oxidize and lose tension after decades. Reseat and clean the contacts before deeper troubleshooting.
• The input signal. Confirm the sensor, wiring and upstream card are delivering a clean signal. The amplifier will faithfully amplify a bad one.

Once you are sure, install the spare, verify the rails, calibrate the loop and check the output end to end before the machine goes back to service.

IC3600AOAJ1A Suffixes, Revisions and Board Markings

The number decodes as IC3600 (the Mark I-II Speedtronic family), AOA (the operational-amplifier function), the J sub-letter (the AOAJ variant), and the trailing 1A revision. Different AOA sub-letters are different variants and are not automatically interchangeable, so match the whole string to the board you are removing. We avoid claiming a specific functional difference between variants where no source confirms one, and instead treat the suffix as a revision or variant that must be matched. The etched GE drawing and date codes on the board itself are the definitive confirmation of the revision you have.

The GE Speedtronic Part Number Decoder walks through how the IC3600 numbering is built, which is handy when an old spares list or drawing references a card you need to verify.

Companion Cards Across the IC3600 Family

The amplifier is one of many single-function boards in a Mark I-II cabinet. Its neighbors include input buffer cards, analog interface cards, function generators, set-point cards, D/A converters and logic boards, and a control signal generally passes through several of them in series. For obsolete hardware, keeping spares across the boards you rely on, not just the amplifier, is a sensible strategy. Browse the companion boards under GE Mark I-II IC3600 Cards and the full Speedtronic selection under GE Speedtronic Turbine Control Boards.

Request a Quote for Your IC3600AOAJ1A

For an exact match, send the full part number IC3600AOAJ1A, any revision or etched board codes, a photo of the board markings, your turbine model, the Speedtronic generation, the quantity and how soon you need it. This item is offered as new surplus, no box, as detailed in the table below.

Use the Request a Quote button and we will get back to you within 24 hours. We deliver worldwide on DDP terms and accept purchase orders.

General Information about the Product
Part Number	IC3600AOAJ1A Mark I-II IC3600
Description	IC3600AOAJ1A By General Electric IC3600AOAJ Amplifier Card NSNB
Condition	newSurplusNoBox With 1 Year Warranty.