When encountering refurbished chips again, how to identify new and old chips?

littleshrimp

When encountering refurbished chips again, how to identify new and old chips? [Copy link]

Having been cheated countless times has given me a keen eye, and I can tell whether a refurbished chip is real or fake as soon as I get it.

This is the DS90C124 I bought from Taobao. The seller described it as brand new and original. I decided to buy it because it was cheap. The price of 14 yuan per piece is probably the price that a normal company would pay for bulk purchases, so I think it's not surprising if I can buy a new one for 14 yuan.

The spot price of this chip is about 70 yuan per chip, and the official price of TI is less than 50 yuan per chip.

This chip looked normal when it was just unpacked. When I took it out and looked at the pins against the light, I basically determined that it was a disassembled product because the pins were very shiny. A normal chip should have tin-sprayed, frosted pins, but this chip was obviously fished out of tin. If the pins were still unsure, the scar on the right side of the chip would have exposed its experience more clearly.

annysky2012

It's OK if it's refurbished and usable, but I'm afraid it's all a scam and there are problems inside

w494143467

Passive trigger of moderator.

chunyang

The most effective way to judge whether it is a disassembled chip is to look at the pins. In addition to the surface features, the end face of the pins can be further judged, and the judgment is the strongest. It is difficult to process the end face even with advanced counterfeiting technology, but a microscope with sufficient magnification is required for observation. In the current extraordinary period, if you want to buy a small number of components, you might as well just look for disassembled chips. The price of a brand new chip is not right, it is impossible. Without strict law enforcement, it is inevitable that there will be scammers everywhere.

dfwisdom

1. Appearance inspection and comparison: Use a microscope to look at the silk screen engraving, mark points, front and back details

2. Compare waveforms of test circuits on suspected chips

littleshrimp

chunyang published on 2021-9-27 16:45 Looking at the pins is the most effective basis for judging whether it is a disassembled piece. In addition to the surface features, the end face of the pins can be further judged, and the judgment is the strongest. Counterfeit powder...

If you look closely at the cross section of the pins of most new chips, you will see the yellow copper inside
. At that time, I saw that this was about the same price as the disassembled machine, so I tried it and made a board in a few days to see if it could be used.

littleshrimp

dfwisdom published on 2021-9-27 16:59 1. Check and compare the appearance: use a microscope to look at the silk screen engraving, mark points, front and back details 2. For the suspected chip, test the circuit and compare the waveform

This is a disassembled machine, the silk screen is not polished, and if it is not damaged, there should be no difference.

chunyang

littleshrimp posted on 2021-9-27 17:28 If you look closely at the pin cross-section of most new chips, you will see the yellow copper inside. At that time, I saw that this was about the same price as the disassembled machine, so I tried it and made a board in a few days to see...

There may not be copper exposure. If the powder foot process is in place, there should be no copper exposure. The tinning of the end face of the disassembled chip is very obvious. The inspection of the end face of the pin can also distinguish some domestic counterfeit products. Because the material requirements of the pin cutting blade are very high, the price is naturally expensive. Some domestic packaging factories will use domestic blades and even use the blades beyond their lifespan to save costs. At this time, the end face of the pin will show obvious edge deformation or even burrs, which can be clearly seen under a microscope.

不足论

The research has reached such a high level.

freebsder

At this time, it would be great if you could buy authentic products, but a good second-hand one would also be fine.