With all of this mess around shortage of Cirrus Logic CS4270 chips I want to share my experience of buying fake one on AliExpress. There is also original one for comparison. The funny part: original one also bought on AliExpress.) I’l try to be as brief as possible.
I’ve bought first IC in July. Price was around 14 USD. Seller with a good feedback. Chip comes in perfectly sealed tape reel package and looks totally new and genuine. After I finished shield I instantly stuck with “Supercollider fail” error. 10 Minutes of tinkering leads me to there is no sound card in system. You can check it easily with
cat /proc/asound/pcm or with
I spend whole next day with looking glass, multimeter and oscilloscope. Everything works perfectly except codec. Soldering was ok: I’ve checked each line from IC to RPi header — no breaks, no shorts. Crystal was fine too.
At this point I realise the chip is fake. I’ve gone mad and bought bottle of acetone to check if IC is remarked or not. Remarking is a popular Chinese tech for selling refurbished ICs. Mine was not remarked. Actually they no need to remark packages like TSSOP-24 — there is plenty of fabs which could sell “blank” package so they only need to engrave any image which will sell.)
Seller do not answer me, so I rise the claim. AliExpress stands to the side of the seller so I’ve got no refund. It was not a surprise: frankly speaking it is a soldered part and my only evidence was a screenshot of dmesg output.
So I placed order for 5 pcs to big and trusted IC reseller company. With 90 days leadtime.) At a same time I bought another IC from AliExpress but told with seller first. He frankly said that IC is refurbished but will work. The price was around 23 USD.
When I’ve got 2nd IC from Ali I immediately noticed the difference with 1st one. It comes into simple zip-lock with remaining of lead on pins. But after soldering (to the same board for sure) it started immediately without any problems. I’ve also tested it with acetone for no reason. It is not remarked.
Here it is the differences:
1. First pin mark on original IC is obviously bigger. I consider this as major difference which is hard to copy.
2. Engraving on both IC is very different (size and placement). You also can compare datecodes. Im pretty sure most of fakes shares their datecodes.
3. At a bottom side original IC has small “CN” mark engraved while fake IC has big ejection pin mark.
If you was scammed with fake or remarked codecs from Ali, Tmall, eBay, please share pics and your observations here. Maybe it helps to form list of features which belongs to fake codecs exclusively so one can avoid them in future.