Should I buy rare transistors on eBay?

No, almost all rare transistor types on eBay are fakes.

Working for many years as a technician and developing excellent supplier contacts, one learns that 1) some parts are no longer available and 2) one should never buy rare transistors on eBay. When unavailable parts appear on eBay or other places targeting the general public, you can be 99.9% certain they are fakes. Walk away, unless you like throwing money away.

This point about retailers that sell to the general public is important because the commercial vendors I use, for example, don’t try to sell parts that we know are no longer available. You could say that their customers are more informed, and as trusted vendors, their behaviour is a little more ethical.

UPDATE, July 2024: I’ve been working on an Accuphase E-202 where the ‘repairer’ told the owner he had to order rare replacement transistors. I’ve tested them, and they are Chinese eBay fakes.

Be wary of anyone sourcing rare transistors from anywhere other than a reputable commercial vendor or specialist semiconductor supplier. No professional repairer sources semiconductors on eBay.

Dreaming

There are many parts I wish were still available, but they’re not, so we move on. Sure, an old guy in Poland may occassionally appear with a handful of otherwise unavailable parts, but you can usually pick these legitimate listings by looking for a variety of markers and other clues. Everything else, like classic Hitachi 2SJ56 and 2SK176, VFETs, certain STK modules etc are fakes. I don’t mean that these parts are probably fakes, I’m saying that they absolutely 100% certainly ARE fakes.

How do I know? I’ve been at this for a while now, nearly 2 decades. I’ve been well mentored, and I have an excellent eye for fake vs real. I use a couple of specialist semiconductor vendors, and if they can’t obtain the parts I need, nobody can. I’ve examined and tested many fake parts over the years and have come to understand what is available, what isn’t and when genuine NOS parts do become available.

The Problem

Unscrupulous sellers know that people are willing to do almost anything to get hold of mythical, unobtainable parts. So, they take existing cheap parts and have them printed with whatever the unavailable part name is. The end-user/tinkerer/hobbyist/ill-informed repairer buys a few and installs them and they fail, or the problem remains… What then?

Are you going to return them to Shenzhen? Good luck with that. How will you know, let alone prove, that the new part is fake? How can you be sure there is not some other reason it failed? Would you even know if the new part or the equipment is performing correctly? Do you want to start an eBay dispute over fake transistors? You will be asked to have them professionally inspected and tested. It’s not worth going down this rabbit hole.

If you took your equipment to an expert, they could test it for you and let you know if the parts are genuine or fake, and what the problem is. This is why I generally avoid fitting customer-supplied parts. If the parts are not sourced from large commercial vendors or other specialist parts suppliers, you can’t trust them. It’s about eliminating variables. There are perhaps one or two good parts sellers on eBay, but that’s it.

Relax

In most cases, rare or unobtainable parts are simply not needed. I have stock of and access to many rare NOS parts, parts that are unavailable to the average shopper. I also keep thousands of modern replacement parts, and I have an extensive database of tested substitutions that I’ve developed over the years. If I have nothing available, I can design solutions to solve most semiconductor problems.