I have discovered a way to check for fakes in circuit provided you have a parallel configuration . Since the TDA 7294 cannot be used in parallel on such boards the second chip would be idle .Put the amp to work without a heatsink and a 100 ohm resistor at the output. The chips are protected from overheating so if you slowly rise the volume both will get equally warm/hot if they truly are genuine and work in parallel . If they are fake one will be idle and might get a bit warm but the working one will be a lot warmer /hot. when both are working in parallel they both generate heat so should be any very nearly the same temperature So burning your fingers on one or both is a reliable indication wether fakes or not since olny the real thing can work in parallel .
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If you have chips on two or more pcb´s you can modify one to work as slave by changing one of the boards to act as slave and provisionally put them in parallel to avoid unsoldering the chips and possibly destroying the pcb. Refer to the TDA spec sheet for indications of what to do ,
see :
TDA7293 - 120 V / 100 W DMOS audio amplifier with mute and standby - STMicroelectronics
see :
TDA7293 - 120 V / 100 W DMOS audio amplifier with mute and standby - STMicroelectronics
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Its just not worth the risk of buying fake components.
I would rather spend a bit more than end up having to rip out parts from the pcb because they have failed and possibly taken an expensive speaker(s) with them.
Here in Spain and in Germany best place is MOUSER , then there is T.E.M. in Poland , their page is almost like Mousers and their shipping superfast , bought four Toroidals there summing 8 kilos and was here in Majorca the next day , shipping was only 9 euros. IMPRESSIVE
Tda 7293 - La frase en busca | Distribuidor de componentes electronicos. Tienda en linea: Transfer Multisort Elektronik
Tda 7293 - La frase en busca | Distribuidor de componentes electronicos. Tienda en linea: Transfer Multisort Elektronik
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Hi!
For the record, I just received two genuine TDA7293 from this German seller on Ebay. Very affordable.
Laser engraved, test pins 5, 10, 11 gives around 3MR and reversing the polarity do not shows any reading.
Before that I have burned some Chinese one
For the record, I just received two genuine TDA7293 from this German seller on Ebay. Very affordable.
Laser engraved, test pins 5, 10, 11 gives around 3MR and reversing the polarity do not shows any reading.
Before that I have burned some Chinese one
Hi thank you ICforensics for the valuable information to test the 7293 a simple method to find out if the component is a counterfeit is to erase the print with acetone remover many TDAs for sale on ebay are marked as original go to Specifications of the object on ebay's page and you will see that for the brand it is stipulated unbranded it is valid for most components as these are oem laserprint
One thing I ask myself is why the manufacturers do not do something a bit more failsafe to avoid their products being used for fakes . At manufacturing level it is not so complicated nor expensive to stamp a number into the visible metal tab , say to the left and/or right of the screw-hole which could be one or two 3 if it is a TDA7293 and a 4 if it is a 94 , and so on , which would make it almost impossible to fake them for reason of too costly for sure......... Or engrave it into the plastic on the side facing the tab by melting it into the plastic , or if the plastic is molded then hardened on top of the die code it into the plastic then and there.
I have tried to contact STM about this but cannot find any DIRECT contact address
It must be in the best interest of any manufacturer to have a fail-safe marking of his products and a differently molded casing for example , one with ribs and another without or different ones , or round or square edges , and which would give 16 different casings , would effectively do the trick while surely low cost at manufacturing level ?????
e.g. voltage-coding of power transistors could even be unified this way............ with the edges announcing the max voltage of the transistor within.
I have tried to contact STM about this but cannot find any DIRECT contact address
It must be in the best interest of any manufacturer to have a fail-safe marking of his products and a differently molded casing for example , one with ribs and another without or different ones , or round or square edges , and which would give 16 different casings , would effectively do the trick while surely low cost at manufacturing level ?????
e.g. voltage-coding of power transistors could even be unified this way............ with the edges announcing the max voltage of the transistor within.
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I have a set of number-stamps (and hammer) in garage. I'm sure I could find a self-feeding motorized stamper on IndiaMart or the Chinese equivalent.
When Windows 95 was anticipated to be widely counterfeited, MS included a hologram in the packaging, figuring fakers could not do that. IIRC, fake copies hit the market before MS did.
About anything worth doing, someone in the world can do cheap enough to profit.
Coincidentally--- on TV they are showing fake credit cards perfect (enough) in every detail to pass scrutiny. (Yes, it is a rerun of an older show.)
Most Class AB chip amps are out of production for the time being, and the stored ones have been sold.
You are better off buying UTC Taiwan or CRC China chip amps, they make 2030 / 2050 / 1875, the last seems available from TI as well.
3886 / 7293 /7294 are available either in small quantities from private stock, or fakes.
Your choice, buy a known copy at a knock off price, about 20% of the original ones, they work in a fashion at least.
Or buy a fake, and risk collateral damage.
Or buy a broken amp, and salvage the chips from there, which is kind of taking a chance.
The ST made 7294 also has a STK like habit of sudden failure, so I think you are better off with a Mosfet design, if you need that kind of output.
You are better off buying UTC Taiwan or CRC China chip amps, they make 2030 / 2050 / 1875, the last seems available from TI as well.
3886 / 7293 /7294 are available either in small quantities from private stock, or fakes.
Your choice, buy a known copy at a knock off price, about 20% of the original ones, they work in a fashion at least.
Or buy a fake, and risk collateral damage.
Or buy a broken amp, and salvage the chips from there, which is kind of taking a chance.
The ST made 7294 also has a STK like habit of sudden failure, so I think you are better off with a Mosfet design, if you need that kind of output.
I have relatives who make orthopedic stuff, they have a laser machine for marking on steel and titanium, about $4000. Smaller versions were cheaper.
So even a laser is not so expensive to use and abuse for faking.
Unless you need to repair / replace, select a device which is available from reputed suppliers, which currently means Class D or Mosfet.
So even a laser is not so expensive to use and abuse for faking.
Unless you need to repair / replace, select a device which is available from reputed suppliers, which currently means Class D or Mosfet.
We have SIM based cards here, and now contact less ones, the latter are being skimmed by abusers in the old parking lot central locking capture scam.
A friend in Canada told me the cards there are still magnetic, the chip cards are a work in progress.
As technology evolves, the idea is to make things safer, but crooks are crooks.
Now the latest we have are apps on cell phones, people point their phone at the QR code at the shop, then put the amount on the phone, and confirm.
The shops have a device that goes ding, or speaks the amount...shop keeper gives thumbs up, or whatever, got the money. The shop device costs about $20.
No cash is handled, safer and more convenient. Money is transferred between bank accounts (not so safe) or electronic wallets.
Of course, your phone could be damaged or stolen...That risk is always there.
A friend in Canada told me the cards there are still magnetic, the chip cards are a work in progress.
As technology evolves, the idea is to make things safer, but crooks are crooks.
Now the latest we have are apps on cell phones, people point their phone at the QR code at the shop, then put the amount on the phone, and confirm.
The shops have a device that goes ding, or speaks the amount...shop keeper gives thumbs up, or whatever, got the money. The shop device costs about $20.
No cash is handled, safer and more convenient. Money is transferred between bank accounts (not so safe) or electronic wallets.
Of course, your phone could be damaged or stolen...That risk is always there.
https://www.st.com/content/st_com/en/contact-us.html
This leads to a page where you select your location, and proceed.
This leads to a page where you select your location, and proceed.
What is the first thing a child should learn in kindergarten? The info in #36, of course:
https://www.st.com/content/st_com/en/contact-us.html
https://www.st.com/content/st_com/en/contact-us.html
Received a fake one off ebay. Listing shows 1100 sold!
Having to looked at various different chips in the past year trying to spot fakes. I think there's also signature striations on fake chips if you look with a magnifying glass. Maybe from whatever process of sanding off the original markings.
Having to looked at various different chips in the past year trying to spot fakes. I think there's also signature striations on fake chips if you look with a magnifying glass. Maybe from whatever process of sanding off the original markings.
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