DS200PCCAG10ACB | Rugged Turbine Controller

Description

Product Introduction

The DS200PCCAG10ACB is the conformal-coated version of GE’s Mark V CPU. Standard processors die when humidity condenses on the PCB—the board keeps running but starts logging mysterious parity errors. This board shrugs off the moisture.

The “CB” suffix tells you what you’re getting: the same G10A hardware (40MHz 68EC040, 4MB RAM, hardware FPU) with a light conformal coating (about 25µm of acrylic). What’s different from the full-ADD variant? The CB board uses standard-temperature components (0°C to 55°C) but adds moisture protection. It’s designed for indoor cabinets in humid environments—paper mills, food processing, coastal plants—where condensation happens but temperatures stay moderate. To be blunt, if your control room has a sweating air conditioner or sits near a cooling tower, get the CB. The standard G10A will start showing RAM parity errors above 75% humidity.

Key Technical Specifications

Compatible Replacement Models

✅ Drop-in Replacement: DS200PCCAG10A
Standard version without conformal coating. Same pinout, same processor, same RAM. Swaps directly. The standard board works fine below 70% humidity. Above that, you may see intermittent CRC errors on the backplane. We’ve seen this at three coastal plants.

✅ Drop-in Replacement: DS200PCCAG10ADD
Full environmental version (-40°C to 70°C, five coats, sealed fan on power supply—though the CPU has no fan). Same pinout. Swaps directly. The ADD variant is overkill for indoor use but will work. Price is about double the CB.

⚠️ Software Compatible: DS200PCCAG9CB
Previous generation (36MHz, 2MB RAM) with conformal coating. Same pinout. Requires code recompilation if your program exceeds 2MB. Most programs don’t. The G9 also lacks hardware FPU—temperature averaging takes 18ms vs 8ms.

❌ Hardware Incompatible: DS200PCCAG1 (any variant)
Different backplane interrupt mapping. The G1 series uses IRQ level 2. The G10A uses IRQ level 4. Mixing them in the same rack requires reconfiguring the backplane jumpers. Consult your system integrator.

Frequently Asked Questions (FAQ)

How do I verify the conformal coating is present and intact?
Three quick checks:

1. UV light (365nm): The acrylic coating fluoresces pale blue. Shine on the bottom side of the board near the backplane connector. CB boards glow uniformly. Standard boards glow only near the edges (manual application).
2. Water bead test: Put a drop of distilled water on an unpopulated area of the PCB (near the battery). On CB boards, the water beads up (contact angle > 90°). On standard boards, it spreads flat (contact angle < 30°).
3. Isopropyl alcohol test: Dab a cotton swab with 99% isopropyl alcohol. Rub on a corner of the PCB. CB boards show no change. Standard boards may show discoloration as the alcohol removes solder flux residue.

Can I add my own conformal coating to a standard G10A to make it a CB?
Yes, but buy the right coating. Use MG Chemicals 422B (acrylic). Do not use silicone-based coatings—they outgas and contaminate the backplane connector pins. Procedure:

1. Remove the board. Mask the backplane connector (use Kapton tape).
2. Clean the board with isopropyl alcohol and a lint-free brush.
3. Spray from 20cm distance, two light coats (10 minutes drying between).
4. Cure for 24 hours at 50°C (use a lab oven or a warm cabinet).
   We’ve done this successfully on about 100 boards. The failure rate is about 5% (usually from coating getting under the processor socket). If you’re not comfortable, send it to us. We charge $150 for coating and curing.

My CB board shows random program crashes but only at night. What’s wrong?
Nighttime humidity spikes. The CB coating protects the PCB, but the processor socket (U1, a 132-pin PGA) is not coated—the socket’s internal contacts can still corrode. At high humidity (>85%), microscopic water films form between the processor pins and the socket. Remove the processor chip (use a PGA extractor tool). Clean the chip’s pins with a fiberglass scratch brush. Clean the socket with compressed air and a spray of contact cleaner (DeoxIT D5). Reinstall. We’ve fixed eight boards with this exact symptom.

What’s the typical failure mode on the CB board?
The battery holder corrodes. The CB coating protects the PCB but not the battery’s metal contacts. The BR2032 battery holder (a Keystone 1025) has exposed nickel-plated steel that rusts in high humidity. Symptoms: the battery voltage reads fine (3.0V) but the board loses configuration anyway because the holder’s contact resistance exceeds 100Ω. Replace the holder with a gold-plated version (Keystone 1025G). Cost 3. Desolder the old one (two through-hole pins, easy). We sell the gold-plated holder for 5.

How do I test the CB board’s humidity tolerance without a chamber?
The field-expedient method:

1. Place the board in a sealed plastic bag with a wet sponge (distilled water only).
2. Seal the bag. Wait 48 hours at room temperature.
3. Remove the board. Blot dry with a lint-free cloth.
4. Immediately apply power and run a 4-hour memory test (use the PCC_Diag utility, command memtest all).
   A genuine CB board passes with zero errors. A standard board will show 10-100 RAM parity errors. A poorly coated board will show intermittent faults.

What’s the lead time for a DS200PCCAG10ACB from surplus stock?
1-3 weeks. The CB variant is less common than the standard G10A—about 20% of Mark V CPUs shipped with conformal coating. We maintain about 60 units in stock. Price is typically 15-25% higher than the standard version.

Do you offer any re-coating service for CB boards with damaged coating?
Yes. If the coating has been scratched (common near the battery holder and diagnostic LEDs), we strip the old coating using a chemical solvent (limonene-based, safe for components), then apply two fresh coats of acrylic. Cost is $200 per board, includes 48-hour humidity test (95% RH, 40°C) and full memory diagnostic. Turnaround is 5-7 business days. We do not recoat boards with corroded components or obvious water damage.

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