How to find obsolete industrial parts

When a drive, PLC module, sensor or relay is discontinued, the manufacturer stops selling it, but plenty of units are still out there. Here's how to track one down.

1. Get the exact part number

Read the full catalog number off the nameplate, including any suffix or series letter. Small differences often mean a different voltage, firmware or mounting, so search the complete number and note the brand.

2. Check whether a replacement exists

Manufacturers often publish a recommended successor for discontinued products. A direct replacement can be faster and cheaper than hunting for old stock — but check that wiring, dimensions and software still match.

3. Know where old parts end up

• Industrial surplus dealers buy leftover stock from plant closures and upgrades.
• Repair and refurbishment shops sell tested, rebuilt units and often offer a warranty.
• Authorized distributors sometimes still hold "new old stock" (NOS) after a product is discontinued.
• Online marketplaces list used and new-in-box parts from many small sellers.

4. Search many sites at once

Checking every dealer by hand takes hours. Part Finder searches across vendor sites for a part number and shows price, condition and stock in one list. You can also add your own trusted vendor sites to search first.

5. Check the listing before you buy

• Compare the part number in the photos with the one in the title.
• Confirm the condition: new, new old stock, refurbished, or used.
• Ask about testing, warranty and return policy.
• Watch for prices far below the rest of the market.

6. If nothing turns up, keep watching

Rare parts appear and sell quickly. A Part Watch checks for your part daily or weekly and emails you when a matching listing shows up.