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/diy/ - Do It Yourself

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File: 558 KB, 1600x1200, DSCN4978.jpg [View same] [iqdb] [saucenao] [google]
1135558 No.1135558 [Reply] [Original]

I want to share a lesson I learned today: Be careful when ordering certain chips from Ebay. This was supposed to be the speech synth chip used in a speak-and-spell and other 80s toys, but it's garbage with a fake label etched into it.

I built the test circuit and noticed there was a problem right away because the chip was getting hot. I went over my circuit 20 times looking for a problem then started disconnecting Vcc and Gnd wires looking for the problem. I eventually found a two pins that are supposed to be high impedance input but on my chip output Vcc.

I did some googling and found other people had been ripped off with fake SP0256. Some signs that should have been obvious: Microchip never manufactured an SP0256. The label is laser etched which wasn't done in the early 80s. The pins show signs of desoldering even though it's supposed to be new.

>> No.1135562

>which wasn't done in the early 80s.

Really? I'm honestly surprised. How did they do it before?

>> No.1135564

well, it's obvious that you have to watch out on eBay and AliExpress and online vendors, I think everyone who buys chips and semiconductors online has experienced this. What bugs me in this case is, why the hell would anyone bother to make a fake speech synth chip when they could milk out much more cash if they sold something like fake audio frequency amplifier ICs, most of the people in the diy electronics scene build only shitty audio amplifiers, after all. Looks like chinks can't into con-business.

>> No.1135565

>>1135562
Hammer and a chisel

>> No.1135568
File: 544 KB, 1600x1200, DSCN4986.jpg [View same] [iqdb] [saucenao] [google]
1135568

>>1135562
They used a silk screen stencil and paint. Bottom chip is laser engraved, top chip is stenciled.

>> No.1135569

>>1135564
This chip was sold for around $15 at Radioshack back in the day. Now it's discontinued and twice as much.

>> No.1135570

>>1135568
I prefer the paint one.

>> No.1135582

Oh yeah, that's not uncommon with old chips that are now somewhat rare. There are a ton of fake MOS6581 (SID) chips for the Commodore 64 on eBay. Normally you can expect to pay 40$ for one these days, but there's always a few "mich cheaper" chinese ones that are either defective or are something entirely different with a fake label.

>> No.1135603

>>1135564
>they could milk out much more cash if they sold something like fake audio frequency amplifier ICs

Isn't this just every audiophile op-amp sold by chinese vendors on Ebay/Aliexpress?

>> No.1135605

>>1135558
i bought some LM138 5A linear regulators off a chinese ebay seller. they fried far from the 5A so i cracked them open and put the chip under a microscope. after a few seconds i saw printed in the corner '317'. they were stuffing lm317 1.5A (probably less than that) into TO3 cases and labeling them lm138. that was the last time i buy cheap semis from china.

>> No.1135630
File: 195 KB, 1411x748, 1487902591818.jpg [View same] [iqdb] [saucenao] [google]
1135630

had one in my parts drawer

>> No.1135632
File: 160 KB, 1543x656, 1487902579213.jpg [View same] [iqdb] [saucenao] [google]
1135632

support mpu

>> No.1135645

>>1135570
I bet you've never seen one, the paint rubs off after a while

>> No.1136060

>>1135630
Is that a MacBook keyboard with a hacked-in Windows key, or just a ripoff keyboard?

>> No.1136107

>>1136060
It's, probably, one of the win10 laptops, they have this new trapeze-shaped Win logo instead of the old one