Category: Guides

"Product withdrawn from the range. Recommended successor: the new generation." — every maintenance engineer whose machines are more than a few years old knows this message. Discontinued (obsolete) automation parts are a particularly thankless problem: the machine is in good working order and is expected to run for years to come, but the manufacturer has ended production of the series, and with it, service support and spare-part availability are gradually disappearing. In this guide we compare four realistic sources for buying such components, describe the risks of each, and show how to verify both the seller and the specific unit before you buy.

Discontinued automation parts — where does the problem come from?

A machine's life cycle and the life cycle of industrial electronics run at different speeds. A production line or a machining center is designed for decades of operation, while component manufacturers regularly migrate entire product families to new generations. The phenomenon affects practically every product group: frequency inverters (VFD) and servo drives (successive generations of families such as SINAMICS or IndraDrive), PLC controllers, safety technology (the PNOZ or Flexi Soft families), and even switching power supplies (such as the PROmax family). Once a new generation is launched, the previous one moves through "phase-out" status, then "discontinued", until eventually factory repairs come to an end as well.

The trouble is that in automation, replacing a component with a "newer equivalent" is rarely a simple drop-in swap. A new drive generation often means different dimensions and connectors, different firmware and parameterization, different network communication — and therefore changes to the PLC program, to the documentation, and to the spare-parts stock for the entire machine fleet. For components performing safety functions, there is also the need to re-validate the circuit. That is why, as long as the machine is meant to keep running, the fastest and safest scenario is usually a 1:1 replacement — a part with exactly the same part number (MPN) that appears on the nameplate.

Where to buy discontinued automation parts? Four routes

1. Official distribution — the simplest route, but usually a dead end

The first call naturally goes to an authorized distributor. For parts with obsolete status, however, the answer is predictable: the series is unavailable, and the manufacturer suggests a successor from its current portfolio. The successor may be an excellent product, but it is not a 1:1 replacement — which brings us back to the integration problem described above. The official channel is always worth checking, but for discontinued components you need a plan B.

2. Secondary market and marketplaces — availability yes, predictability no

Auctions, marketplaces, and machine dismantling are a source where you can find almost anything. But it is worth being clear about what you are actually buying there: most often used parts pulled from working machines, with an unknown number of operating hours and an unknown history (voltage surges, moisture, thermal overloads). Typical risks include stock photos instead of photos of the actual unit on offer, no real warranty, incompleteness (missing connectors, coding keys, or the backup battery), and problems with purchase documentation. For critical parts — and certainly for safety technology — that is a risk that is hard to accept.

3. Surplus stock (new old stock) — brand new (factory new) parts, even though unavailable from the manufacturer

The third route is the least known and often the best: surplus stock, also known as new old stock (NOS). These are brand new (factory new) components that were never installed — bought as spares for projects, left over from investments and upgrades, or sitting in maintenance department warehouses. Such a part carries the same MPN as the original in the machine, is in factory condition, and offers full traceability. This is the model RECOSTOCK is built on: we buy back surplus automation stock from plants all over Poland, and then offer them as brand new parts — with a warranty and a VAT invoice.

4. Modernization (retrofit) — a long-term solution, not an emergency fix

The fourth option is to move forward instead: replacing the entire drive or control system with the current generation. Sometimes it is unavoidable, but it is an engineering project — equipment selection, program rewriting, electrical work, commissioning, and planned downtime. A retrofit makes sense as a strategic decision spread over time, not as a reaction to a breakdown in the middle of the production season. In practice, the two approaches complement each other well: an NOS surplus part keeps the machine running and buys you time to plan the modernization for a convenient date.

Source	Part condition	Availability of discontinued series	Main risk
Official distribution	New (current generation)	Usually none — successor offered	The successor is not a 1:1 replacement
Secondary market / marketplaces	Used, unknown history	Wide	No warranty, condition not as described
Surplus stock (NOS)	Brand new, never installed	Depends on surplus stock supply	Requires seller and MPN verification
Modernization (retrofit)	New (current generation)	Not applicable	Project cost and planned downtime

How to verify the seller and the specific part before purchase?

Regardless of the source, it is worth running through a short checklist before ordering:

1. The full part number (MPN) from the nameplate. Compare the number on the nameplate of the component in your machine with the number in the listing character by character — including version suffixes. In drive and controller families, a seemingly minor difference at the end of the number can mean a different power supply variant, communication option, or firmware version.
2. Photos of the actual unit, not stock catalog images. A trustworthy seller photographs the exact unit that will actually be shipped: the nameplate, the condition of connectors and contacts, seals, and packaging.
3. Warranty stated in the listing. For discontinued series, the seller's warranty replaces manufacturer support — check its duration and terms before you buy.
4. VAT invoice. A proper proof of purchase is the basis for accounting, complaints, and audits — on the secondary market, that is not always a given.
5. Completeness of the delivery. Connectors, coding keys, documentation — a missing minor accessory can hold up the replacement for days.

Take particular care with components responsible for safety functions — safety relays and safety controllers. Here, factory-new condition and an exact part number match are not a matter of convenience, but a prerequisite for preserving the machine's safety function.

Discontinued parts in practice: how RECOSTOCK works

RECOSTOCK is a Polish shop and buyback service for industrial automation components. We sell exclusively brand new (factory new) parts sourced from surplus stock (new old stock): PLC controllers, drives and servo drives, power supplies, pneumatics, safety controllers, CNC electrospindles, I/O modules, and connectors. Every product is identified by the MPN from its nameplate, and the photos in the listing show the exact unit you will receive. On top of that come clear terms: a 12-month warranty on every part, dispatch within 24 hours (courier or parcel lockers), and a 23% VAT invoice.

Where to start?

• Check the availability of your part in RECOSTOCK shop — the fastest way to find it is by searching for the MPN from the nameplate.
• Your part number isn't listed? Ask about it via our contact form — provide the full MPN from the nameplate and, if possible, attach a photo of it.
• Do you have your own surplus stock left over from projects or upgrades? We buy it: a quote within 48 hours and collection from anywhere in Poland.

FAQ

How does an NOS part differ from a used or refurbished part?

An NOS (new old stock) part is brand new (factory new) — it has never been installed or powered up in a machine; it comes from surplus stock, not from current production. A used part has already run in a machine, while a refurbished part has additionally undergone repair. RECOSTOCK sells exclusively brand new (factory new) parts from surplus stock.

Can a discontinued part come with a warranty?

Yes. Manufacturer support and the seller's warranty are two independent things. At RECOSTOCK, every part — including those from series the manufacturer no longer produces — is covered by a 12-month warranty, and each purchase is documented with a VAT invoice.

How can I make sure a part will fit my machine?

The key is the full part number (MPN) from the nameplate of the component installed in your machine — including the suffixes that define the version. Compare it with the number in the listing and with the photo of the nameplate of the unit on offer. If in doubt about the hardware or firmware version, ask the seller before you buy.

What if the part is not available in the shop?

Report the part you are looking for via the contact form, providing the full MPN from the nameplate and, if possible, a photo of it. We buy surplus stock from all over Poland, so our inventory changes regularly — it is worth leaving an enquiry even if the item is not currently listed in the shop.

A failed frequency inverter (VFD), power supply, or safety relay can bring an entire production line to a halt — and if the manufacturer has already discontinued the series, the standard distribution channel is no longer an option. Buyers and maintenance engineers are then left with three routes: brand new surplus stock parts (known as new-old-stock, NOS for short), refurbished components, and used parts. Each of these options has its place, but they differ in risk level, warranty, and certainty of origin. We compare them fairly — with no marketing spin.

What are surplus stock parts (new-old-stock)?

New-old-stock components are brand new, never installed and never powered up. Where do they come from? Manufacturing plants and automation integrators buy more parts than they ultimately need: for projects whose scope later changed, as spares for machines that were subsequently upgraded, or as a stock buffer for the maintenance department. When a company clears out its warehouse or decommissions a line, these new, unused parts enter the secondary market — often still in their original packaging.

On the surplus market you can therefore find, for example, drives from the SINAMICS or IndraDrive families, PNOZ safety relays, programmable safety controllers such as Flexi Soft, or power supplies from the PROmax series — exactly the same products that once sat on an authorized distributor's shelf. The difference lies in the route the part took to reach the buyer, not in its technical condition.

The key distinction: new-old-stock is not the same as a refurbished or used part. These categories are often mixed up in listings, which is why it pays to know what to ask the seller.

Three categories on the secondary market — definitions with no sugar-coating

Refurbished parts

These are components that have run in a machine and were then repaired: capacitors, fans, power transistors, bearings, or contacts were replaced. The quality of refurbishment depends entirely on the workshop — from the scope of replaced components, through load testing, to the repair documentation. A proper refurbishment by a specialized service center is a fully legitimate solution; an anonymous “refurbishment” limited to cleaning the housing is a different story altogether.

Used parts

Components removed from running or scrapped machines and sold “as is”. No wear parts have been replaced, and the operating history — running hours, ambient temperature, overloads, short-circuit events — usually remains unknown. This is most often the cheapest option, but also the biggest unknown.

Surplus stock parts (NOS)

Brand new (factory new), unused parts sourced from plant and integrator surplus. Their technical condition matches that of parts from regular distribution; the only points to check are storage conditions and — for electronics with electrolytic capacitors kept in storage for very long periods — the possible need for capacitor reforming, which is worth asking the seller about before first power-up.

Comparison: surplus stock parts vs refurbished vs used

Criterion	New from surplus (NOS)	Refurbished	Used
Certainty of origin and condition	High — the part has never been in operation; its condition can be verified against the nameplate number and photos of the specific unit	Depends on the service provider — requires repair documentation and a test report	Low — load and failure history is usually unknown
Warranty	Provided by the surplus seller (at RECOSTOCK: 12 months)	Depends on the refurbishing company and the scope of repair	Often none, or only the seller's statutory liability
Operational risk	Comparable to a part from official distribution	Moderate — depends on the quality of refurbishment	Highest — wear components are closer to end of life
Availability	Also covers discontinued series, as long as they circulate in surplus stock	Good for popular, high-value components (drives, spindles)	Wide but random — depends on machine teardowns
When to choose	Critical machines, safety systems, parts discontinued by the manufacturer	High-value components when NOS is unavailable and the service provider is credible	Non-critical machines, test rigs, limited budget

When surplus stock parts win

In two situations, the advantage of NOS is particularly clear.

First: discontinued components. A machine's lifecycle is usually longer than the lifecycle of the electronics controlling it. The manufacturer ends support for a series and announces a successor — yet the machine still has to keep running. Replacing a drive with a newer generation often means changes to wiring, parameterization, and sometimes the supervisory software as well. A brand new (factory new) part from surplus stock, identical down to the part number (MPN), allows a true one-to-one replacement — with no modifications and no compatibility risk. This applies especially to drives and servo drives, where firmware version compatibility and matching motor parameters genuinely matter.

Second: safety system components. Safety relays and safety controllers — families such as PNOZ or Flexi Soft — are responsible for the effectiveness of a machine's safety functions. In devices with relay outputs, the switching endurance of the contacts (described by the B10d parameter) is consumed with every operation. With a used part, you never know how much of that service life is already gone; with a new part from surplus stock, the counter starts at zero. That is why, for safety circuits, it is sensible to choose brand new (factory new) components — you will find them among our safety controllers.

It is also worth adding to this list any machine whose downtime generates high costs: process bottlenecks, continuously running lines, machine tools with CNC electrospindles. There, saving money on a part with an unknown history rarely pays off.

When used or refurbished parts make sense

To be fair: you do not always have to buy new. A used part can be a rational choice when:

• the machine is not critical to production, and its downtime stops nothing beyond the machine itself;
• the component goes to a test bench or a training mock-up, or serves as a donor of subassemblies during diagnostics;
• the budget is a hard constraint and the risk of premature failure has been consciously accepted;
• a part is needed "right now" to temporarily get the machine back up and running.

Refurbishment, in turn, holds its ground for expensive components — higher-power drives, CNC electrospindles, power modules — when a new unit is no longer available anywhere, including surplus stock. The condition: a credible repair service, a documented scope of repair, and testing under load.

How to safely buy parts from surplus stock

The secondary market for automation components can be opaque, so before buying it is worth checking a few things:

1. Identification by MPN. The foundation is the part number from the nameplate — it is this number, not the general series name, that determines interchangeability. At RECOSTOCK, every product is identified precisely by MPN, and the photos in the listing show the exact unit you will receive.
2. An unambiguous declaration of condition. The seller should state outright: brand new (factory new) from surplus stock, refurbished, or used. If the description avoids this — ask.
3. Warranty in writing. RECOSTOCK provides a 12-month warranty on brand new (factory new) parts from surplus stock, and every purchase is documented with a 23% VAT invoice — which matters both for accounting and for any potential claims.
4. Logistics. When a breakdown strikes, time is what counts — at RECOSTOCK we ship orders within 24 h, by courier or to parcel lockers.

There is also the other side of this market: if your plant itself keeps unused PLC controllers, power supplies, I/O modules or pneumatics from completed projects on its shelves, RECOSTOCK offers automation surplus buyback with a quote within 48 h — just fill in the form and we arrange collection from anywhere in Poland.

Summary: match the category to the machine, not to the price

The "NOS, refurbished or used" decision should not start with the price, but with the question: what happens when this part fails? For critical machines, safety circuits and discontinued components, NOS combines certainty about the technical condition with availability that official distribution no longer provides. For secondary machines and test applications, used parts remain a sensible, cheaper alternative — with a conscious acceptance of the risk.

If you are looking for a specific part number — a controller, drive, power supply or I/O module — check the current range of brand new (factory new) surplus parts in the RECOSTOCK shop. Every item is identified by MPN, with photos of the actual unit and a 12-month warranty.

FAQ

What is the difference between a new-old-stock part and a refurbished one?

A new-old-stock part is brand new (factory new) — it has never run in a machine and comes from the surplus stock of a plant or a system integrator. A refurbished part has been in service, has failed or worn out, and has been repaired: selected subcomponents were replaced. NOS retains the full service life of all its components; in a refurbished part, only what the repair covered has been renewed.

Do surplus stock parts come with a warranty?

The warranty is provided by the surplus seller, not by the manufacturer — so its duration and terms need to be checked before purchase. At RECOSTOCK, all brand new (factory new) surplus parts are covered by a 12-month warranty, and we issue a 23% VAT invoice for every order.

Where do parts sold as surplus stock come from?

From the warehouses of manufacturing plants and automation integrators: from projects that changed scope, from maintenance department stock left over after line upgrades, and from inventory clean-ups. RECOSTOCK sources them, among other channels, through its surplus buyback with a quote within 48 h and collection from anywhere in Poland.

Can a used safety relay be installed in a safety circuit?

Formally, that is decided by the machine's risk assessment and documentation, but technically it is a bad idea: the switching life of the contacts is consumed with every operation, and with a used unit there is no way of knowing how much is left. For components such as PNOZ or Flexi Soft, it is safer to choose a brand new (factory new) unit.

A completed investment project, a decommissioned line, a technology change or standardization of the machine park — in each of these scenarios, brand new (factory new) automation components are left on the shelves that no one will ever install. PLC controllers, frequency inverters (VFDs), servo drives, power supplies and safety relays can tie up significant capital in the warehouse, and their value only declines over time. The solution is industrial automation buyback — a service that puts surplus stock back into circulation as spare parts for maintenance departments, while your company recovers cash and warehouse space. In this guide we show how to prepare your surplus for sale and what the process at RECOSTOCK looks like step by step.

Where automation surplus in manufacturing companies comes from

Automation surplus stock, also known as new-old-stock (NOS), consists of brand new (factory new) components that never made it into a machine. In practice, it arises in a few typical situations:

• Project leftovers — the integrator or the investment department orders parts with a margin, and after the line is commissioned, the excess controllers, I/O modules and power supplies stay on the shelf.
• Technology change or standardization — the plant switches, for example, from one drive family to another, and the entire service stock for the old platform becomes redundant.
• Plant closures and relocations — when production is shut down, the spare parts warehouse often contains unopened components in their original packaging.
• Excess service stock — parts bought “just in case” for a machine that has since been upgraded or sold.

Why surplus stock loses value with every passing year

Automation manufacturers regularly phase out older product families and replace them with new platforms. As long as a given series is still widely used in running machines, a brand new (factory new) unit from surplus is a sought-after commodity — maintenance departments are happy to reach for it, as it avoids rebuilding the control cabinet for the successor model. But as the machine park is gradually replaced, demand shrinks and the same part becomes harder and harder to sell. Then there is physics: electrolytic capacitors in frequency inverters (VFDs) and power supplies age even while sitting on the shelf, seals in pneumatic components lose their elasticity, and warehouse humidity damages packaging and promotes corrosion of connector contacts. The conclusion is simple: the sooner surplus stock goes back into circulation, the more it is worth.

Industrial automation buyback — how to prepare a list for a quote

A fast and reliable quote starts with the unambiguous identification of every item. In automation, a single family covers dozens of variants: a SINAMICS series frequency inverter or an IndraDrive servo drive comes in many power ratings and option configurations, a PNOZ safety relay has variants differing in the number of channels and supply voltage, a Flexi Soft safety controller is built from different modules, and a PROmax power supply comes in many voltage and current versions. That is why what matters is the full part number (MPN) from the nameplate, not just the series name.

Step 1: write down the numbers from the nameplates

Walk through your shelves and note down the complete MPN from each nameplate along with the quantity. Avoid blindly copying numbers from purchase documents or your ERP system — it happens that the box contains a different version than the paperwork says. If the part is shrink-wrapped, you will usually also find the number on the packaging label.

Step 2: photograph the nameplates and packaging

A photo of the nameplate resolves doubts faster than any description. Photograph the nameplate or label of every item, and for larger lots also take a general shot of the shelf or pallet. Good photos speed up the quote and eliminate mistakes when identifying the variant.

Step 3: describe the packaging condition and completeness

Note whether the packaging is original and intact, whether the manufacturer's seals remain unbroken, and whether the connectors, documentation and mounting accessories are included. This information directly affects the quote, so it is worth providing it right in your submission.

What raises and what lowers the quote for surplus stock

Even among brand new (factory new) components, quotes can vary considerably. From the buyer's perspective, what matters is certainty that the part is exactly the variant they are looking for and that no one has installed it before. The table below summarises the key factors:

Raises the quote	Lowers the quote
Original, intact manufacturer packaging	No packaging or substitute packaging
Intact seals and anti-static protection	Broken seals, signs of opening
Completeness: connectors, documentation, mounting accessories	Missing items from the set
Legible nameplate and full MPN	Illegible markings, uncertain identification
Product families still widely used in industry	Very niche items that are hard to verify

How industrial automation buyback works at RECOSTOCK

The process is deliberately simple and predictable — from submission to settlement:

1. Form on the website — you send us a list of items: MPNs, quantities, and photos of the nameplates and packaging.
2. Quote within 48 hours — based on the list and photos, we prepare a specific price offer for the entire lot.
3. Collection from anywhere in Poland — once the offer is accepted, we arrange collection of the goods, no matter where in the country your warehouse is located.
4. Invoice-based settlement — you settle the sale of surplus stock like any other B2B transaction, with a complete set of documents for your accounting department.

What happens to the components after buyback

Surplus stock we buy back goes to the RECOSTOCK store, where every product is identified by the number from its nameplate and the photos show the exact unit from our warehouse — the buyer sees precisely what they will receive. Components, from drives and servo drives to power supplies and safety controllers, are covered by a 12-month warranty and shipped within 24 hours with a VAT invoice. Your surplus stock doesn't end up as scrap — it genuinely extends the life of machines in other plants.

Do you have items on your shelves that will never be picked for production again? Prepare an MPN list following the steps above and send it via the quote form — you will receive a response within 48 hours.

FAQ

Do I need to know the part numbers of all the components?

Identification is always based on the full MPN from the nameplate, but you don't have to copy it out by hand. A legible photo of the nameplate or the packaging label contains all the markings and makes it possible to determine the exact product variant unambiguously.

Can I sell just a few items, or does the buyback only cover entire warehouses?

We quote every enquiry individually based on the list you send. Whether you have a few units left over after a completed project or are clearing out a warehouse after a plant closure, the easiest way is simply to submit an enquiry through the form — you will receive a specific offer for the whole batch within 48 hours.

How do collection and settlement work?

Once the quote is accepted, we arrange collection from anywhere in Poland and settle the transaction based on an invoice. You sell the entire batch in a single transaction — no listings to post, no shipping to individual buyers, no retail-level settlements to handle.

Does RECOSTOCK also buy back parts removed from machines?

We specialize in brand new (factory new) components from surplus stock (new-old-stock). If you are not sure how to classify a given batch, describe its condition in your enquiry or ask via contact form.