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A LAB GAVE AWAY AN ELECTRON MICROSCOPE IT COULD NOT FIX. HE GOT IT RUNNING AGAIN

A lab could not repair its JEOL scanning electron microscope and gave it away for free; ProjectsInFlight spent months bringing it back to life.

by ProjectsInFlight

FULL CAD BOM FIRMWARE DOCS

ScienceWorkshop

difficulty
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time
months
license
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WHAT YOU’LL NEED

Videos
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COMPAREE VERDICT

This is not a weekend project and it is not a from-scratch build. It is a months-long repair of a specific instrument, a JEOL JSM-5200 scanning electron microscope from the late 1980s or early 1990s, which the previous lab could not repair and gave away for free. The faults ran from a blown fuse to a shorted transformer, bad DC-DC converters, a broken vacuum pump and perished hoses and seals. The video is a documentary, not a tutorial: you see how an SEM works, what went wrong and how he fixed it, but there is no step-by-step guide and no list of parts to order. Two things made the repair possible: the machine came with its manual and schematics, and an online community of SEM enthusiasts helped, including someone with the same model to compare against. The hardest part is not only the repair. It is finding such a machine in the first place, then having the space, the high-voltage safety knowledge and the months of evenings to work through failures one at a time. If you have never repaired mains-voltage equipment or worked with vacuum systems, this is the wrong first project. If you have, this video shows what is possible. The one thing most likely to go wrong: you get a machine with a failure you cannot diagnose or a part you cannot source, and it stays broken.

GOOD TO KNOW

  • —This is a rescue story, not a build guide — there are no CAD files, no BOM, no firmware to flash.
  • —The 35-minute video is a repair documentary: what broke, how he diagnosed it, what he replaced.
  • —No repository exists — this is not an open-source project.
  • —The machine itself was free, but parts, test equipment and the space to work on a console-sized instrument are not.
  • —You cannot buy this model new; you acquire one by watching surplus auctions and being ready when a lab upgrades.
  • —There is no licence because there is nothing to licence — this is a repair, not a design release.

Parts to buy

3 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • Scrapped scanning electron microscopeFind
  • Replacement parts as failures are diagnosed (fuses, transformers, vacuum pumpsFind
  • Test equipment (multimeter, vacuum gauge)Find

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Can I build this?

Printnothing required
Buya scrapped scanning electron microscope (watch university/lab surplus auctions), replacement parts as failures are diagnosed (fuses, transformers, vacuum pumps — all specific to the machine you acquire), test equipment (multimeter, vacuum gauge)
Toolsworkshop space for a console-sized instrument, high-voltage safety knowledge, multimeter, hand tools, the machine's manual and schematics, possibly machine shop access for custom parts
Skillselectronics repair at mains voltage and above, vacuum system diagnosis, patience to work through undocumented failures — this is advanced troubleshooting, not assembly
Timemonths — the video spans months of evenings, and your timeline depends on what is broken and how fast you can source parts
Cost$$$ — the microscope itself was free, but no repair cost is given, and direct replacement parts for an old SEM are often impossible to find or very expensive. Your budget depends entirely on what has failed.
SafetyReal hazards: mains voltage and high-voltage electron gun circuits throughout, vacuum implosion risk if seals fail during testing, X-rays if the machine is powered incorrectly or shielding is damaged. This is not a beginner-safe project — you are working on equipment designed for trained lab techs. If you do not already know how to safely work on mains-voltage equipment, do not start here.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

I Saved an Electron Microscope from the Trash35:00

How a scanning electron microscope works, how he got this one and repaired it, and examples of what it can image.

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Gallery

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Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Watch the full 35-minute video to understand what you are committing to (This is not a build tutorial — it is a repair documentary; you are watching to learn what can go wrong and how long it takes)
  2. 2.Read the Hackaday coverage for context on the rescue (Covers the same story with additional links and community discussion)
  3. 3.Start watching university and lab surplus auctions for scrapped SEMs(The machine was free because the lab had given up on it — you are looking for the same situation, which means months of watching and waiting)

KNOWN ISSUES

  • You acquire a machine with a fault you cannot diagnose or a part you cannot source — every SEM is different, and some failures are unrecoverable without manufacturer-specific components that no longer exist.
  • You underestimate the space required — these machines weigh hundreds of pounds and need a stable bench, dedicated power, and room to open panels for repair.
  • You do not have high-voltage safety experience — the electron gun runs at kilovolts, and the power supply circuitry is lethal; this is not the project to learn on.
  • You assume the video is a step-by-step guide — it is a documentary of one specific rescue, not a universal repair manual; your machine will fail differently.
  • You miss the time commitment — months of evenings is not an exaggeration, and that assumes you can source parts; some waits are weeks long.
  • You pay for a 'non-working' SEM at auction without knowing what is broken — free is the right price for a machine that might be unrecoverable; paying hundreds or thousands for an unknown fault is a gamble.

Can I build a scanning electron microscope from scratch?

Not from this project. This is a repair of a scrapped commercial instrument, a JEOL JSM-5200 from the late 1980s or early 1990s, not a from-scratch build, and there are no design files to work from.

Where do I find a scrapped SEM?

University and lab surplus auctions, directly from labs that are upgrading, or online surplus sites. The key is finding one that is being scrapped (free or near-free) rather than sold as repairable (expensive and often still broken).

What if I cannot find the exact part that failed?

You fabricate a replacement, source a used part from another scrapped unit, or find a modern equivalent — this is the core challenge of the project and the reason it takes months.

Is there radiation risk?

The electron beam itself is contained and shielded, but X-rays are generated during operation — commercial SEMs are designed with shielding and interlocks to prevent exposure. If shielding is damaged or interlocks are bypassed, there is real risk. Do not operate the machine with panels open or shielding removed.

How much does it cost if the microscope is free?

The video does not give a total. What it shows is that direct replacement parts for an old SEM are often impossible to find or very expensive, so expect creative workarounds. Vacuum pumps, transformers and test equipment are the likely costs, and they depend entirely on what has failed in your machine.

Community builds

No community builds yet — be the first, we feature the best ones.

Discussion1

FROM THE COMPAREE TEAM

A blown fuse, a shorted transformer, dead DC-DC converters and a broken vacuum pump — and it still came back to life. If you found a scrapped SEM, which failure would make you walk away, and which would you take on?

CompareeTEAM1mo agoedited

Practical notes from our verification: there is no repository, no build guide and no parts list — this is a repair story told in a video, not a project release. The machine is a JEOL JSM-5200 scanning electron microscope from around the late 1980s or early 1990s that had been deemed irreparable and was headed for scrap. It came with its manual and schematics, which made the repair possible at all, and the creator got help from an online community of SEM enthusiasts, including someone who owned the same model. The faults were a mix of age and failure: a blown fuse that led to a shorted transformer, bad DC-DC converters, a broken vacuum pump, and perished hoses and seals, with some remaining CRT issues likely from aging capacitors. If you are watching surplus listings and have high-voltage and vacuum repair experience, this shows what is possible; every scrapped SEM fails differently, so treat it as inspiration, not a recipe. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

ProjectsInFlight

ProjectsInFlight runs a home lab and documents it on YouTube. The JEOL JSM-5200 scanning electron microscope came from a lab that could not repair it and gave it away for free; he brought it back to life over months of troubleshooting with help from an online SEM community.

Star the project on GitHub

DISCLAIMER

  • Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
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