DS3800DCCB1C1C Mark IV | Replacement Comms Module for GE

Description

Product Introduction

The coastal plant had a problem: salt air, high humidity, and a cabinet that was never sealed properly. The standard DCCB modules lasted 4 years before the PCB traces corroded and the communications failed. The DS3800DCCB1C1C has a conformal coating on the PCB, protecting it from moisture, salt, and airborne contaminants. It’s the same communications module, but it’s built to survive. Swapped the standard DCCB for a C1C variant, and it’s been running for 10 years without a failure.

GE’s DS3800DCCB1C1C is the core communications module for the Mark IV Speedtronic turbine control system with the added protection of conformal coating. It manages the data transfer between the CPU module, the I/O modules, and the external HMI and engineering workstations. The module has a dedicated communications processor, multiple serial ports (RS-232, RS-422), and supports the proprietary Mark IV network protocol. The “C1C” suffix indicates the conformal coating—a thin polymer layer that protects the PCB from moisture, salt, dust, and chemical attack.

Key Technical Specifications

• Processor: Communications coprocessor (dedicated)
• Communications Ports: 2 x RS-232, 2 x RS-422 (configurable)
• Protocols: Mark IV proprietary, Modbus RTU (optional)
• Scan Rate: 1 ms typical (data transfer)
• Data Capacity: 512 KB buffer
• Redundancy: Supports dual redundant configuration (active/standby)
• Conformal Coating: Acrylic-based polymer coating on PCB (both sides)
• Connector Type: 37-pin D-sub (field communications)
• Backplane Connector: 96-pin DIN (VME form factor)
• LED Indicators: Module status (green), communications activity (flashing), redundancy status
• Operating Temperature: –30 to +65 °C ambient
• Humidity Resistance: 95% non-condensing (coated PCB)

Quality Inspection Process (SOP Transparency)

This is what every DS3800DCCB1C1C goes through before it ships. The conformal coating adds a few extra steps:

Incoming Verification: The OEM packing slip is matched against the shipping manifest. Visual inspection includes checking the GE holographic label, verifying the 96-pin backplane connector is straight and has no bent pins, and examining the PCB for any signs of rework—flux residue, non-matching solder joints, or missing silkscreen. We also check the 37-pin D-sub connector for bent pins. The conformal coating is inspected for uniformity—there should be no bubbles, cracks, or missing spots. The coating must cover all components and traces.

Live Functional Test: The module installs in a Mark IV test rack with a backplane simulator and a known-good CPU module (CXCIA). Power-on self-check: the LED should illuminate green, then flash to indicate communications activity. We connect a test HMI (engineering workstation) to the DCCB’s RS-232 port and verify the module responds to requests.

We test the serial ports by sending and receiving test messages at 9600, 19200, and 38400 baud. For the redundancy test, we install a second DCCB1C1C in the rack and configure them as a redundant pair. We force a failover by disconnecting the primary’s backplane connection and measuring the switchover time.

We also perform a data integrity test: we send a large data packet (512 bytes) from the CPU to the I/O modules and back, verifying the data is transferred without errors.

Conformal Coating Inspection: We inspect the coating with a UV light (the coating contains a fluorescent tracer). Any spots that don’t fluoresce indicate missing coating. We also perform an adhesion test by applying and removing a piece of tape—the coating must not peel off.

Electrical Parameters: A Fluke 1587 insulation tester measures isolation between the communications ports and the backplane. We look for >20 MΩ at 500 VDC. Power consumption is measured at idle and at full load.

Mechanical Inspection: The VME connector is inspected for bent pins. The D-sub connector is inspected for bent pins. The mounting holes are checked for alignment.

Final QC & Packaging: The QC report lists the communications test results, the redundancy failover time, the data integrity test, the conformal coating inspection, and the isolation measurements. The module goes into a new anti-static bag with a tamper-evident seal, then into a double-walled carton with foam inserts. A “QC Passed” label with the test date and technician’s ID goes on the outer box. All test data and photos are available on request.

Field Replacement Pitfalls

The DCCB1C1C is a ruggedized communications module—but it’s not indestructible. Here’s the field-tested list:

Conformal Coating Damage
The conformal coating can be damaged by excessive heat, chemicals, or physical abrasion. If the coating is scratched or cracked, moisture can get underneath and corrode the traces. I had a plant where a technician used a solvent-based cleaner on a C1C module—the solvent dissolved the coating, and the module failed 6 months later. ❗ Use only isopropyl alcohol (70% max) for cleaning. Don’t use acetone, MEK, or other aggressive solvents.

Baud Rate Mismatch
The DCCB1C1C’s serial ports must be configured to match the HMI and engineering workstation baud rates. I had a plant where a technician replaced a DCCB1C1C and didn’t set the baud rate switches correctly—the HMI was dead. ❗ Photograph the old module’s baud rate switches before removal. Replicate them on the new module.

Redundancy Configuration
The DCCB1C1C supports redundant pairs, but the redundancy must be configured in the firmware. I saw a plant install a second DCCB1C1C “just in case” but never configure the redundancy. When the primary failed, the turbine lost communications. ❗ Redundancy is a configuration setting. You must enable it. The default is simplex.

Cable Termination
The DCCB1C1C’s RS-422 ports require proper termination. If the cable is unterminated, the communications will be intermittent. I had a plant where an RS-422 cable was unterminated, and the HMI would drop out every few minutes. ❗ RS-422 requires termination at both ends. The DCCB1C1C has a termination jumper—verify it’s set correctly.

D-Sub Connector Damage
The DCCB1C1C uses a 37-pin D-sub connector. If the cable’s connector is damaged, you can force it in upside down—or bend the pins. ❗ Inspect both the cable’s D-sub connector and the module’s connector for bent pins before you mate them.

Get these five right and you’ll cut rework time by 90%.

New Original vs. Refurbished: Why It Matters

The DS3800DCCB1C1C is a legacy communications module with conformal coating. Refurbishment risk is significant.

New Original (New Surplus) means this unit came from GE’s production line, sealed in an ESD-safe bag. The conformal coating is fresh and uniform. The module has zero operating hours. The serial number traces to GE’s production database.

Refurbished risk: The conformal coating and the communications processor are the biggest issues. A refurbished C1C module may have been coated at the factory, but the coating may have been damaged during removal or rework. A refurbisher may also have repaired the module and re-coated it—but the re-coating is rarely as good as the factory coating. I saw a refurbished DCCB1C1C in a plant where the coating was missing over a repaired component; moisture got in, and the module failed. The refurbished module cost 1,300; the new surplus unit was 1,700. The turbine lost communications and tripped, costing $40,000.

Real cost: A communications failure can cause a loss of HMI visibility and potentially a turbine trip. The cost of a trip is tens of thousands of dollars. A new surplus module is cheap insurance.

What we provide: We include a photo of the OEM packing slip with the GE part number and serial number. The anti-static bag is sealed with a tamper-evident label. The QC test report lists the communications test, the redundancy failover test, the conformal coating inspection, and the isolation measurements. You get a 12-month warranty.

Pricing context: Our price sits 30-50% above refurbished alternatives but 20-40% below GE’s current factory list price.

Performance Benchmarks & Test Results

Measured during our QC test. Conditions: test rack with a Mark IV backplane simulator and a CXCIA CPU module, 24.0 VDC supply (Fluke 8845A), ambient 24 °C, firmware v3.0.

• Serial Port Test (RS-232): Successfully communicated at 9600, 19200, and 38400 baud. No bit errors over a 1-hour test with 100,000 messages.
• Serial Port Test (RS-422): Successfully communicated at 9600, 19200, and 38400 baud. No bit errors over a 1-hour test.
• Data Integrity Test: 512 bytes transferred from CPU to I/O and back. Checksum verified. No errors.
• Redundancy Failover Time: 42 ms from primary failure to secondary taking over communications. Within the 50 ms spec.
• Conformal Coating Inspection: Uniform coating coverage under UV light. No bubbles, cracks, or missing spots. Tape adhesion test passed.
• Humidity Test: The module was placed in a humidity chamber at 95% RH, 40 °C for 24 hours. After the test, the module’s communications ports remained functional, and insulation resistance remained >20 MΩ at 500 VDC.
• Power Draw: 3.5 W at idle. 4.2 W at full load. Within the 5 W max spec.
• Isolation Resistance (Comms Ports to Backplane): Measured 45 MΩ at 500 VDC—well above the 10 MΩ minimum.
• MTBF (Published): GE’s datasheet listed 210,000 hours at 40 °C for the DCCB1C1C. Based on field data, expect 15-20 years of service under normal conditions.

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