GE DS3800DCMC In Stock | New Surplus Mark IV Memory Pack

Description

Product Introduction

The memory faults were intermittent—random bit flips, occasional application crashes, and a turbine that would trip without warning. The problem was the memory controller: the Rev B controller had a rare timing bug that showed up under high-backplane-traffic conditions. The DS3800DCMC has the Revision C memory controller, which fixes that bug. Swapped the Rev B module for the Rev C variant, and the intermittent faults stopped.

GE’s DS3800DCMC is the core memory module for the Mark IV Speedtronic turbine control system with the Revision C memory controller. It provides memory expansion for the CPU module (DS3800CXCIA), storing the turbine control application, configuration data, and historical trend logs. The module has 1 MB of battery-backed RAM and 2 MB of EPROM (program storage). The “C” suffix indicates the Revision C memory controller, which includes fixes for timing issues and improved error handling. The “C” revision also improves compatibility with newer backplane revisions.

Key Technical Specifications

• RAM: 1 MB (battery-backed)
• EPROM: 2 MB (program storage)
• Battery: 3.6 V lithium (field-replaceable)
• Memory Controller: Revision C (bug fixes, improved error handling)
• Backplane Connector: 96-pin DIN (VME form factor)
• Data Retention: 5 years (battery-backed RAM)
• Access Time: 85 ns (improved over Rev B)
• LED Indicators: Module status (green), memory access (flashing), error (red)
• Operating Temperature: –30 to +65 °C ambient
• Storage Temperature: –40 to +85 °C

Quality Inspection Process (SOP Transparency)

This is what every DS3800DCMC goes through before it ships:

Incoming Verification: The OEM packing slip is matched against the shipping manifest. Visual inspection includes checking the GE holographic label (or classic Speedtronic logo), 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 battery—if it’s bulging or leaking, we replace it immediately. The EPROMs are inspected for any damage (the windows should be covered with labels).

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. We perform a memory test: we write a pattern to the RAM and verify it reads back correctly. We then test the battery backup by removing the power supply and waiting 60 seconds, then re-applying power—the RAM must retain the data.

We test the Rev C memory controller by running a comprehensive stress test: high-speed backplane traffic (simulating a fully loaded I/O rack), random memory access patterns, and error injection (simulating bus errors). The Rev C controller must handle all of these without bit errors or faults. We also test the controller’s error handling by corrupting the bus data and verifying the controller recovers correctly.

We also test the EPROM by comparing its checksum to the OEM’s database.

Electrical Parameters: A Fluke 1587 insulation tester measures isolation between the memory module and the backplane. We look for >20 MΩ at 500 VDC. Power consumption is measured at idle and at full access—must be <2 W.

Mechanical Inspection: The VME connector is inspected for bent pins. The battery is checked for proper seating and voltage (3.6 V ±0.1 V). The EPROM windows are checked for intact labels.

Final QC & Packaging: The QC report lists the memory test results, the Rev C controller stress test, the battery voltage, the EPROM checksum, 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 DS3800DCMC is the latest memory module. Here’s the field-tested list:

Battery Failure
The DS3800DCMC has a 3.6 V lithium battery that backs up the RAM. If the battery fails, the RAM loses the data—the turbine control application or configuration may be lost. I had a plant where a DCMC was swapped, and the new module’s battery was dead—the turbine wouldn’t start. ❗ Check the battery voltage before you install the module. It should be >3.5 V. If it’s below 3.0 V, replace the battery before installation.

Memory Addressing Conflicts
The DCMC’s memory addresses must be configured to match the CPU’s memory map. If the addresses conflict, the module won’t be recognized. I had a plant where a DCMC was installed but the CPU couldn’t see the memory—the address switches were set incorrectly. ❗ Check the address switches on the DCMC. They must match the CPU’s memory map. Photograph the old module’s switch positions before removal.

Rev C Controller and CPU Firmware Compatibility
The Rev C memory controller is backward-compatible with older CPU firmware, but to take full advantage of the error handling improvements, you need CPU firmware v4.0 or later. I had a plant where a DCMC was installed with a CPU running v3.0 firmware; the module worked, but the error handling features were disabled. The fix was upgrading the CPU firmware. ❗ The Rev C controller is compatible with v3.0, but you need v4.0 for full error handling. Check your CPU’s firmware version.

Backplane Compatibility
The Rev C memory controller is designed for Rev C and later backplanes. If you install it in a Rev A or Rev B backplane, the timing may be marginal. I had a plant where a DCMC was installed in a Rev A backplane; the module would occasionally fail to access memory. The fix was upgrading the backplane. ❗ Verify your backplane revision before installing the DCMC. Rev C or later is recommended.

EPROM Corruption
The EPROM on the DCMC stores the firmware. If the EPROM is corrupted, the module won’t function. I had a plant where a DCMC’s EPROM had a bit flip; the module would intermittently fail to boot. ❗ The EPROM window must be covered with an opaque label. If the label is missing, the EPROM may have been corrupted by UV light. Check the label before installing the module.

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

New Original vs. Refurbished: Why It Matters

The DS3800DCMC is a legacy memory module with the latest controller. Refurbishment risk is moderate.

New Original (New Surplus) means this unit came from GE’s production line, sealed in an ESD-safe bag. It may have been sitting on a shelf for 10-15 years, but it’s never been installed. The Rev C controller has never been stressed, the battery is fresh, the EPROM is intact, and the module has zero operating hours. The serial number traces to GE’s production database.

Refurbished risk: The battery and the Rev C controller are the biggest issues. A refurbished DCMC may have been pulled from a decommissioned turbine with 50,000+ hours on it. The Rev C controller may have been stressed by the previous environment. I saw a refurbished DCMC in a plant that failed 4 months after installation—the controller’s error handling circuitry failed, causing bit flips. The refurbished module cost 800; the new surplus unit was 1,100. The turbine tripped, costing $40,000.

Real cost: A memory failure can cause a loss of application data, leading to 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 memory test results, the Rev C controller stress test, the battery voltage, the EPROM checksum, 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 (firmware v4.0), 24.0 VDC supply (Fluke 8845A), ambient 24 °C.

• Memory Test: RAM: all 1 MB tested without errors. EPROM: checksum matched GE’s database.
• Rev C Controller Stress Test: High-speed backplane traffic (simulated), random memory access patterns, and error injection. The controller handled all tests without bit errors or faults. Error recovery time: <10 ms.
• Battery Voltage: 3.62 V (fresh battery). Within the 3.5-3.8 V spec.
• Data Retention: With power removed for 60 seconds, the RAM retained the test pattern. After 24 hours, the RAM still retained the test pattern.
• Access Time: 85 ns. Within the spec.
• Power Draw: 1.2 W at idle. 1.9 W at full access. Within the 2 W max spec.
• Isolation Resistance (Memory to Backplane): Measured 40 MΩ at 500 VDC—well above the 10 MΩ minimum.
• MTBF (Published): GE’s datasheet listed 230,000 hours at 40 °C for the DCMC. Based on field data, expect 15-20 years of service under normal conditions.

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