Key Technical Specifications

Parameter	Value
Processor Type	80386EX
Clock Speed	25 MHz
User Program Memory	32K Bytes
Typical Scan Rate	0.22 ms/K
Operating Temperature	0 to 60°C (32 to 140°F)
Power Requirement	+5 VDC @ 670 mA
Communication Protocols	SRTP, Modbus TCP/IP, SNP/SNP-X
Expansion Capacity	1 CPU Base + 7 Expansion/Remote Bases
Programming Software	Proficy Logic Developer PLC Machine Edition
Supported Languages	Ladder Diagram (LD), Instruction List (IL), Structured Text (ST), C-Block

 

Product Introduction

I’ve pulled a lot of these 44A730240-G01 boards out of dusty control cabinets over the years. They are the workhorse single-slot CPU modules for older GE distributed control setups, built around an 80386EX processor running at 25MHz. You typically find them managing real-time links via SRTP or Modbus TCP/IP while executing ladder logic across a main base and up to seven expansion bases.Engineers stick with this specific board because it’s predictable and doesn’t require a massive footprint. With 32K bytes of user memory and a scan rate of 0.22 ms/K, it handles standard process control without choking. Just be warned: this is a 386-era piece of silicon. It is notoriously sensitive to power supply ripple, so if your backplane 5VDC is drifting, it will lock up faster than you can blink. Treat the power supply well, and this board will keep running.

Quality SOP & Tech Pitfalls

The Lab Report
I don’t trust “tested” stickers from random eBay sellers. Before this 44A730240-G01 leaves our bench, it goes through a strict protocol. First, we do a visual and counterfeit check under magnification to ensure no trace corrosion or fake ICs. Next, it goes on a live test rack where we run it for 4 hours, pushing the 80386EX to verify it doesn’t overheat. We pull out the Fluke 115 to check insulation resistance and verify the 670mA draw is within spec. Finally, we log the firmware revision and seal it in anti-static packaging.The Engineer’s Warning
Here is where people mess up: they assume all 44A730240-G01 boards are identical. They aren’t. The firmware revision matters immensely. I once watched a maintenance tech swap in a “new” board, only to spend six hours chasing ghost SRTP communication timeouts because the new board had a newer firmware rev that changed the handshake timing slightly. Always photograph your old DIP switches and jumper settings before pulling the board. I’ve seen guys lose half a day because they forgot how the GBC/GCM option module jumpers were set. ESD is also a killer here; the 386EX is ancient tech and hates static. Wear your wrist strap.

 

Installation & Configuration Guide

1. Pre-Installation: ⚠️ SHUT DOWN AND DISCHARGE. Turn off the +5 VDC supply and wait 60 seconds for the capacitors to bleed off. Take high-resolution photos of the old board’s DIP switches, jumpers, and wiring. Verify your power supply is outputting a clean 5VDC before proceeding.
2. Removal: Label every wire with a sharpie or tape. Release the DIN clips or backplane locking mechanisms gently. Do not pry from the edges of the PCB; pull evenly to avoid bending the backplane pins.
3. Installation: COPY THE DIP/JUMPER SETTINGS EXACTLY. This step prevents 90% of startup failures. Align the 44A730240-G01 squarely with the backplane and press firmly but evenly until seated. Reconnect your wiring exactly as photographed.
4. Power-On & Testing: Restore the +5 VDC power. Watch the LED boot sequence. If the fault light stays solid red, kill power immediately and check your 5V rail. If it boots green, connect via Proficy Logic Developer, verify the 32K memory reads correctly, and run a quick online test to confirm Modbus/SRTP links are alive.

Compatible Replacement Models

Replacement Tier	Model / Action	Notes
✅ Drop-in Replacement	44A730240-G01 (Same Rev)	Must match firmware revision exactly. No logic changes required.
⚠️ Software Compatible	44A730240-G01 (Newer Rev)	Hardware fits, but requires logic recompile and SRTP timing adjustments. Budget 2-4 hours of engineering time.
❌ Hardware Mod Required	Modern GE PACSystems	Requires new chassis, rewiring, and full program migration. Only do this if doing a full system upgrade.

 

Frequently Asked Questions (FAQ)

Can I hot-swap this CPU module?
Absolutely not. This is a single-slot CPU running a 386EX processor. Pulling it while energized will likely fry the backplane traces and destroy the new board. Always kill the 5VDC power first.Is this board still being manufactured by GE?
No. The 44A730240-G01 is long obsolete. What we sell is New Surplus—factory-sealed boards pulled from old industrial stock. They are brand new, but GE hasn’t made them in years. That’s why verifying the exact revision you need is critical before buying.Why does my new board keep dropping Modbus TCP/IP connections?
Check your network cabling and termination first. The built-in LAN port on these older 386-based boards is 10/100Base-T but lacks modern EMI shielding. If you’re running the cable next to a VFD drive without proper shielding, the electrical noise will choke the port. Move the cable or add shielding.Do I need to reprogram the PLC when replacing this board?
If you get the exact same revision, no. The program lives in the RAM/Flash on the board, but if you have a battery backup or flash memory, it should retain the logic. However, I always recommend downloading the latest verified backup from your engineering workstation just to be safe. Don’t trust 20-year-old flash memory.What programming software does this use?
You need Proficy Logic Developer PLC Machine Edition. It supports Ladder Diagram, Instruction List, Structured Text, and C-Block. If you’re still using the ancient DOS-based Logicmaster software, it’s time to upgrade your programming environment.How do I know if my board is failing or if it’s just a power supply issue?
Measure the +5 VDC at the backplane connector under load. If it dips below 4.75V when the CPU is running, your power supply is dying, not the CPU. These 386 processors are surprisingly tolerant of bad power right up until the moment they aren’t. Fix the power supply first.