MICROSCRAPPINGE-waste field guide
Boards · Tier C

Industrial Control Boards (PLC/DCS/SCADA)

Check the part number against a live obsolete-parts market before you touch it — a working Triconex, Foxboro or 1756 module that scraps for four dollars sells for eight hundred to a plant that cannot legally shut down to upgrade.

Au 0.05–0.20 g/lb typical I/O; 0.25–0.60 g/lb CPU and backplanes; 0.6–1.5 g/lb 1970s–80s ceramic-DIP DCSAg 1–8 g per relay moduleCu ~113 g/lb
eBay typical$3–12per lb
Refiner pays$20per lb
Metal in it$40.5per lb at 4 Aug 2026 spot
Confidencelowof the yield figures

How to spot it

Rectangular plug-in cards 100–250 mm in coloured plastic housings with a front terminal block or D-sub, LED status arrays, a keying tab and a gold-fingered or DIN 41612 pin edge at the rear. Markings: 1756-IB16, 1771-IFE, 6ES5/6ES7, 140-CPU-xxx, MC-PDIS/TC-, FBM2xx, 3623T/3805E, IS200/IC693. Backplanes are large FR4 boards with rows of card-edge sockets. Found in refineries, chemical plants, power stations, water treatment, pulp and paper, pharma and offshore.

Metal content

MetalQuantityNotes
Gold0.05–0.20 g/lb typical I/O; 0.25–0.60 g/lb CPU and backplanes; 0.6–1.5 g/lb 1970s–80s ceramic-DIP DCSAll estimated, heavily model-dependent
Silver1–8 g per relay moduleAgCdO/AgSnO2/AgNi relay contacts — pull relays and run them as a separate silver stream
Copper~113 g/lbTraces, transformers, chokes. Ta caps run 5–40 g/lb and are payable at some refiners

At 4 Aug 2026 spot prices that works out to $40.5 per pound of contained metal — Gold 0.2 g = $26.1, Palladium 0.25 g = $10.3, Silver 1.5 g = $2.85, Copper 113 g = $1.21. A refiner paying $20 returns about 49% of that, which is normal: refining costs money and the buyer takes a margin.

Safe removal

Working temperature: Hot air 300–350 °C or solder pot 250 °C

Pull cards under maintenance lockout. To de-populate: shear off the gold-fingered edge and DIN connectors into the high-grade stream, snip ceramic and gold-lidded DIPs separately, pull relays and process them as silver rather than with the boards, and remove transformers, heat sinks, steel brackets and terminal blocks as base metal. Hot air at 300–350 °C or a solder pot at ~250 °C for bulk removal.

Hazards

🔥 Lithium battery fire

A standard ABC extinguisher will NOT stop a runaway lithium cell. Don't count on one.

🌡 Mercury

NEVER vacuum a mercury spill — it aerosolises it. Use a mercury spill kit or sulphur powder, or call your local hazmat line.

☠ Cadmium

NEVER grind, burn, torch or braze cadmium-plated or AgCdO material, and don't inhale the black contact dust.

🛢 PCBs (polychlorinated biphenyls)

NEVER puncture, drain, burn or bin a suspect unit. Burning PCBs produces dioxins and furans.

☠ Lead — dust more than fume

NEVER dry sweep or use compressed air on a scrapping bench. HEPA-vac or wet-wipe only.

☢ Radioactive materials

NEVER grind, sand, saw or incinerate anything that might contain thorium or radium. Sealed sources stay sealed.

🧱 Asbestos

NEVER cut, drill, sand, tear or blow out suspect material with compressed air.

Before you scrap it

The single highest resale-to-scrap ratio anywhere — commonly 50–500×. A Triconex safety module scraps for ~$5 and sells for $800–6,000; an Allen-Bradley 1771 analogue card scraps for $3 and sells for $150–600. Even confirmed-faulty modules sell $20–200 as core exchanges. Never bulk-scrap a legible AB, Siemens, Modicon, Honeywell, Foxboro, Yokogawa, ABB or Triconex part number.

The common trap

Industrial boards are heavy so they must be rich — the opposite is true. Relays, terminal blocks, optos, transformers, steel brackets and thick housings are 60–75% of the mass and carry no gold, so a pallet of I/O cards averages worse per pound than consumer motherboards. The far more expensive trap is scrapping working obsolete modules: a $4 scrap decision routinely destroys $500–3,000 of value.

Questions

How much gold is in industrial control boards (plc/dcs/scada)?

Gold: 0.05–0.20 g/lb typical I/O; 0.25–0.60 g/lb CPU and backplanes; 0.6–1.5 g/lb 1970s–80s ceramic-DIP DCS. Silver: 1–8 g per relay module. Copper: ~113 g/lb. At current spot that is about $40.5 of contained metal per pound.

How do you identify industrial control boards (plc/dcs/scada)?

Check the part number against a live obsolete-parts market before you touch it — a working Triconex, Foxboro or 1756 module that scraps for four dollars sells for eight hundred to a plant that cannot legally shut down to upgrade.

How do you remove industrial control boards (plc/dcs/scada) safely?

Pull cards under maintenance lockout. To de-populate: shear off the gold-fingered edge and DIN connectors into the high-grade stream, snip ceramic and gold-lidded DIPs separately, pull relays and process them as silver rather than with the boards, and remove transformers, heat sinks, steel brackets and terminal blocks as base metal. Hot air at 300–350 °C or a solder pot at ~250 °C for bulk removal.

Is industrial control boards (plc/dcs/scada) worth more working than as scrap?

The single highest resale-to-scrap ratio anywhere — commonly 50–500×. A Triconex safety module scraps for ~$5 and sells for $800–6,000; an Allen-Bradley 1771 analogue card scraps for $3 and sells for $150–600. Even confirmed-faulty modules sell $20–200 as core exchanges. Never bulk-scrap a legible AB, Siemens, Modicon, Honeywell, Foxboro, Yokogawa, ABB or Triconex part number.

Related in Boards

Cell phone boards Boards · $25–40/lb Au 0.09–0.50 g/lbAg 0.23–1.26 g/lbPd 0.025–0.07 g/lbCu 12–56% A Telecom / military boards Boards · $11–35/lb Au 0.3–4 g/lbAg 1–8 g/lbPd 0.02–0.3 g/lbCu 15–25% A Telecom backplanes Boards · $10–18/lb Au 1–3 g/lb wholeAg 0.5–2 g/lbCu 20–30% A Laptop motherboards Boards · $10–18/lb Au 0.20–0.50 g/lbAg 1–3 g/lbPd 0.02–0.08 g/lbCu 15–25% B Server motherboards Boards · $9–16/lb Au 0.05–0.3 g/lbAg 1–3 g/lbPd 0.02–0.10 g/lbCu 15–25% B Wire-wrap / pin boards Boards · $20–35/lb Au 0.6–1.5 g/lbAg 0.5–2 g/lbCu 20–30% B

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