counterfeit ICL7660SCPAZ?

[MAO]

I just received a lot of 10 supposed ICL7660SCPAZ from a Chinese ebayer (I know, I know, but have had good luck in the past)

Everyone one of these has a high pitch squeal when connected as a voltage doubler.

The same DLSMK3 circuit works well and is quiet using a LT1054 with pin 1 lifted.

Is there a known way to test if these are legit or good? Other than what I just experienced?

[rocket88]

man i hate when that happens. it's happened to me once before with a seller from china too. here's what i used to try and tell if the IC or transistor for that matter as soon as i get in an order.

i've got a few chinese ebay sellers that are actually reliable, at least so far. one big key that throws me to thinking the part is fake is i look closely at the pic to see if it looks sanded, and look at the printing. if it looks kinda questionable i skip it. also, i don't know these ones cost you, but i also go by the price. i try to get a good deal, but if it's too low i skip it, like the case with anything from polida. as soon as i get them in i test a few out in a build that works, if there's issues (sounds off, squeals, etc.) i fire off an email to the seller.

also, for chinese sellers i check their rating, anything below 99.5 i skip them, and look at recent feedback to see if there's any red flags.

[MAO]

Well, turns out this seller's rating is just 99.1%...good call Rocket.

The IC's lettering look legit, I don't see any sanding and the "S" appears to be original, they all look similar and consistent.  

Either a very good counterfeiting job, or these were previously damaged.

The last good batch I had purchased from China, that seller's rating is 99.6%.  Going to try them again.

Maybe we should start a thread for recommended overseas ebayers :0)

[MAO]

Well, got burned again.

All 25 of the 2nd order are squealing.

The pedal is quiet with a known good LT1054 and a TC1044.

For awareness, these were the Ebayers.

good-module   99.1% positive feedback
xiumeche-0   99.6% positive feedback REFUND ISSUED 06/16

No refunds given as of yet, just the same response over and over.  

Going to see if EBAY will make it right.

[Travis]

I've had a lot of problems with 7660S and 1054 from Tayda squealing. One weird thing is that the pitch changes when I touch the IC with my finger

I'm close to being done messing around with the things. Just so problematic.

One question, did you have more than one charge pump powered up on the same power supply? If you have two high frequency oscillators like a pair of charge pumps, you can get issues with heterodyning where the two frequencies combine to make a lower (audible) frequency

[MAO]

Hey Travis,
Its just the one pedal with one charge pump. DLS MKIII

I just pulled a 7660S from a quiet Supreaux Deux, and its quiet in the DLS

So I have a known good 7660s, TC1044 and LT1054, all quiet.

All 35 of those 7660S' just purchased squeal like crazy,  Frustrating!

Going to try Polida.

[Travis]

I wonder if there's a huge bad batch going around or something? All charge pump ICs I've bought from tayda in the past year or so have been no bueno

[blorvak]

I had this exact same problem (that you guys helped me diagnose in the troubleshooting forum), and ordered new ones from Ele-Parts on eBay that work just fine. Just a tip. Got them a few months ago.

[MAO]

Cool, I'll see if they still have some and we can test Travis' question about bad parts flooding the market.

[Hozy31]

I bought 30 from polida2008 in October last year and so far all have been good.

[MAO]

Cool,

And I actually received a refund today from xiumeche-0.

1st refund ever from China! (Well, maybe my 2nd refund)

[Kinski]

last year I bought a whole batch from polida. All were bad. Every single one went up in actual smoke. I thought I was going crazy. Got some more from a different supplier and all was fine.

[rocket88]

and that's one example of why polida is on the list of sellers to avoid, in the seller thread. well right now they're the only ones of that list. lol. because they've consistently fucked people over.

[Kinski]

Yep, that was my first and last time ordering from them.

[MAO]

Wow, completely missed that thread, thanks rocket88!

[rocket88]

no prob mao. just started it a few days ago, so by all means add whatever you can.

kinski - i used to get good parts from polida and ordered from them fairly often. i did this up untill a few years ago once everyone started getting a lot of bad parts, and since then i've blacklisted them so to speak.

[reddesert]

Tayda advertises some ICL7660CPAZ - no "S", so no frequency boost. I bought a couple, they work but squeal, but the chips are labeled SCPAZ. So somebody faked the "S" part, but Tayda is listing them correctly as no-boost. Perhaps they got stuck with the fakes. But it would certainly be confusing if one fished the chip out of a stash later and went by the labeling.

If you are in the US, Smallbear sells TC1044SCPA that are just as cheap as you can get any of the other charge pumps, and should be reliable.

[BetterOffShred]

I bought a batch of 7660's from Tayda like a year ago and just got around to using one .. boom, high pitched squeal.  I'll probably order some TC1044 from smallbear when I get around to it.
-Brett

[BetterOffShred]

I used the 7660 in my Echo Dream 2 build, and once I got it working properly the high pitched squeal is only noticeable turned all the way up.  So it's there, but it's not super bad.  That being said, it's bad enough I want a new chip
-Brett

[zedsnotdead]

Hello, what about SMD 7660/1044 parts? I am witing for this to arrive, and then I am hoping to use some SOP8-to-DIP adapters... What do you guys think?