Aliexpress retailer of rare chips - cautionary tale

[6v6gt]

One of my current projects (my desk is littered with current projects) is a retro 8 bit CPU composed entirely of logic chips. The design uses specific ALU chips which are now quite rare so I ordered 5 of these. The supplier sent the wrong chips and I have now been promised a full refund directly by Aliexpress through their disputes procedure. Fortunately the chips were clearly not the ones had ordered which saved me the trouble of testing them and probably made it easier to register a dispute.

Anyway, here are the chips, top side and underside. The first thing to notice is how clean and consistent the Texas Instruments chip markings are. Then look at the variety of packages these markings appear on.

I'll not mention the name of the retailer. Suffice to say that if you are considering using a retailer you have not previously used, look not only at the overall reputation but also look at the recent negative (one/two star) ratings.

Top side

underside

[er_name_not_found]

I resell on ebay. I regularly test the products that I get from resellers other than mouser and digikey. From aliexpress I tend to catch about 10% fakes (at least bad enough that I can tell with my very limited experience.)

A little trick that I've found is asking ali sellers for samples. Many that know they are selling junk will refuse or try to overcharge you to discourage sampling.

[Paul_KD7HB]

There are reputable gray market vendors. We use to buy quantities from them on occasion. I do not have any names right now. But I recall one that was in Florida would actually cut the cover off ICs and verify under a microscope that they matched a known good unit. They bought from all around the world and often would report finding bad batches, not counterfeit batches.