Author Topic: El cheapo amp scam!!!!  (Read 8887 times)

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Offline elex_enthusiast

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El cheapo amp scam!!!!
« on: October 04, 2015, 12:39:08 pm »
A neighbor asked me to fix his amp complaining that it doesn't sound anymore. Told him to bring it to my workshop so I can try to fix it. It powers on but doesn't sound at all, so maybe there was something wrong on the main amp that prevents the relay to latch up. I opened it and I was surprised and stumbled upon seeing this :o

Some of the output trannies looked different  than the others which was quite suspecting..hmm


Due to curiosity I unscrewed the amp board so I can look closer at the top and solder side and this are what I've found. The are no solder joints on those weird looking transistor, short unsoldered legs and its bullshit! Its not a real component.. Its just a three legged plastic thing that marked with the same part number as real ones.



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Obviously it's plastic!!!!
[url=http://postimg.org/image/vi7smoqv9/full/]




The front end


So to speak the whole thing is a crap. It worked again after I replaced the shorted pair of power output transistors and flame proof resistors on one channel. Tested it for a couple of hours and its good to go.


I wonder why the government permits such scam to happen here or why they allow such products with fake (or dummy parts) to be sold. It's seems to me that scamming was quite a game here. Does this this kind of things (consumer electronics scam) do happen in your country? Please let us know. Perhaps you have some story to tell..

Best regards,
Elex
« Last Edit: October 04, 2015, 12:47:52 pm by elex_enthusiast »
aahh bad english
 

Offline djQUAN

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Re: El cheapo amp scam!!!!
« Reply #1 on: October 04, 2015, 12:49:43 pm »
"I wonder why the government permits such scam to happen here or why they allow such products with fake (or dummy parts) to be sold. It's seems to me that scamming was quite a game here."

You're in the Philippines. Where the government only cares about their own pockets and nothing else.  :palm:
 

Offline BradC

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Re: El cheapo amp scam!!!!
« Reply #2 on: October 04, 2015, 12:50:06 pm »
It's everywhere, but that is a particularly nice example.
 

Offline wagon

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Re: El cheapo amp scam!!!!
« Reply #3 on: October 04, 2015, 12:50:41 pm »
It's common enough.  Look up 'white van scam'.  I'm pretty sure Dave did a video on it, too.
Hiding from the missus, she doesn't understand.
 

Offline elex_enthusiast

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Re: El cheapo amp scam!!!!
« Reply #4 on: October 04, 2015, 12:53:20 pm »
"I wonder why the government permits such scam to happen here or why they allow such products with fake (or dummy parts) to be sold. It's seems to me that scamming was quite a game here."

You're in the Philippines. Where the government only cares about their own pockets and nothing else.  :palm:

Hell yeah! Corruption over rules everything and its sad.  :palm:
« Last Edit: October 04, 2015, 12:56:45 pm by elex_enthusiast »
aahh bad english
 

Offline elex_enthusiast

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Re: El cheapo amp scam!!!!
« Reply #5 on: October 04, 2015, 12:59:19 pm »
It's common enough.  Look up 'white van scam'.  I'm pretty sure Dave did a video on it, too.

Yeah I saw that "white van scam" video. I wonder if this kind of scams do happen on EU countries  and US states.. :-//
aahh bad english
 

Online mikerj

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Re: El cheapo amp scam!!!!
« Reply #6 on: October 04, 2015, 01:53:46 pm »
I don't quite understand why those 'dummy' devices have been fitted (since they can't been seen when the case is fitted) or why this would be considered a scam?  They are clearly optional parts which are wired in parallel with the existing output transistor, with an extra emitter resistor.

 

Offline elex_enthusiast

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Re: El cheapo amp scam!!!!
« Reply #7 on: October 04, 2015, 02:01:21 pm »
I don't quite understand why those 'dummy' devices have been fitted (since they can't been seen when the case is fitted) or why this would be considered a scam?  They are clearly optional parts which are wired in parallel with the existing output transistor, with an extra emitter resistor.

It was quite obvious that those "dummy trannies" were fitted to look as if there is a two pair output transistors installed on the unit. Actually the whole amp board can be seen above the case through the vent holes.
aahh bad english
 

Offline blueskull

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Re: El cheapo amp scam!!!!
« Reply #8 on: October 04, 2015, 02:03:24 pm »
I don't quite understand why those 'dummy' devices have been fitted (since they can't been seen when the case is fitted) or why this would be considered a scam?  They are clearly optional parts which are wired in parallel with the existing output transistor, with an extra emitter resistor.

Circumvent laws. If they promote with inside pictures while the final product doesn't have the parts promoted it would be illegal. If they put something dummy on them, and photo this version to promote, they will be perfectly legal, and, well, you can not tell whether it is a mold or a real transistor in pictures.
 

Offline amyk

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Re: El cheapo amp scam!!!!
« Reply #9 on: October 04, 2015, 02:18:52 pm »
TOBHISY instead of Toshiba :-DD

The traces look real though, so I suppose you could upgrade by adding real transistors in their place.
 

Offline elex_enthusiast

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Re: El cheapo amp scam!!!!
« Reply #10 on: October 04, 2015, 02:26:55 pm »
TOBHISY instead of Toshiba :-DD

The traces look real though, so I suppose you could upgrade by adding real transistors in their place.

Yeah funny brand marking..haha ;D
There's still a space for a one pair addition if the owner decides to upgrade it.
« Last Edit: October 04, 2015, 02:29:19 pm by elex_enthusiast »
aahh bad english
 

Offline blueskull

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Re: El cheapo amp scam!!!!
« Reply #11 on: October 04, 2015, 02:39:18 pm »
Also the part number. The legendary audio amplifier transistor model should be C5200/A1943. The fakes' are C5198 and A1941.

PS. There are C5198 and A1941, but not in this package (TP247). They are in TO3P.
 

Offline elex_enthusiast

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Re: El cheapo amp scam!!!!
« Reply #12 on: October 04, 2015, 02:42:01 pm »
Also the part number. The legendary audio amplifier transistor model should be C5200/A1943.

Even C5200/A1943 had been pirated by some unknown manufacturers mostly from China. Aren't you aware of it? :-//
aahh bad english
 

Offline blueskull

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Re: El cheapo amp scam!!!!
« Reply #13 on: October 04, 2015, 02:56:06 pm »
Also the part number. The legendary audio amplifier transistor model should be C5200/A1943.

Even C5200/A1943 had been pirated by some unknown manufacturers mostly from China. Aren't you aware of it? :-//

As a long time audiophile DIYer lived in China I know where can I get genuine parts. Though, fake parts are everywhere.

For now, I see not too much reason to use these old parts anymore. There are a lot of modern good parts out there.

As digital technology evolves, class D audio amps will eventually replace all other amps except for some really niche markets.
 

Offline Kleinstein

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Re: El cheapo amp scam!!!!
« Reply #14 on: October 04, 2015, 07:28:53 pm »
The C5200 / A1943 transistors are still a good choice - except for beeing prone to get a fake if you don't get them from a reliable source.

Having such obvous fakes is funny - though the amplifier should work at low power and maybe higher impedance, at least until it breaks down. So if there it is not working any more, likely something else is broken.
 

Offline Mashpriborintorg

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Re: El cheapo amp scam!!!!
« Reply #15 on: October 05, 2015, 09:57:13 am »
I have seen a white van scam IRL, at a market near me !  :scared: He sells weird all-in-one speakers (speaker columns with integrated amplifier and radio - mp3 player) and DVD/divx  players with "100 free great movies included"  :palm:
 

Offline Tim F

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Re: El cheapo amp scam!!!!
« Reply #16 on: October 05, 2015, 10:12:24 am »
I don't quite understand why those 'dummy' devices have been fitted (since they can't been seen when the case is fitted) or why this would be considered a scam?  They are clearly optional parts which are wired in parallel with the existing output transistor, with an extra emitter resistor.
Probably not 'optional' in the original circuit designer's eyes. It's likely that this is a result of "lets try removing some parts and see if it still works" by the production line and then trying to make it look like they populated the board properly at a quick glance. If it even has a V-I limiter on the output stage i wouldn't be surprised if it's still configured for dual pairs of output devices and has contributed to the single pair being blown. The working transistors were likely fakes anyway, and wouldn't have held up to the abuse that the real deal would have.
« Last Edit: October 05, 2015, 10:14:34 am by Tim F »
 

Offline G7PSK

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Re: El cheapo amp scam!!!!
« Reply #17 on: October 06, 2015, 01:57:03 pm »
Are they fakes or just duds with the leads cut off.
 

Offline blueskull

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Re: El cheapo amp scam!!!!
« Reply #18 on: October 06, 2015, 02:01:51 pm »
Are they fakes or just duds with the leads cut off.

Looks like fake parts. (Deliberately) wrong brand marking, wrong package (5198 and 1941 are in TO3P as far as I know, not TO247).
 

Offline djQUAN

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Re: El cheapo amp scam!!!!
« Reply #19 on: October 06, 2015, 02:11:37 pm »
I'm wondering if the fake parts contain silicon in them or just a plastic case with cut leads and nothing else.
 

Offline elex_enthusiast

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Re: El cheapo amp scam!!!!
« Reply #20 on: October 06, 2015, 02:27:42 pm »
I'm wondering if the fake parts contain silicon in them or just a plastic case with cut leads and nothing else.


Just barely plastic..not a real part.. As I said it's a dummy transistor.
aahh bad english
 

Offline SteveLy

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Re: El cheapo amp scam!!!!
« Reply #21 on: October 06, 2015, 02:32:41 pm »
The kitsch fonts on the front panel are a dead giveaway. Still, the fake bolted on components are something special.
 

Online Gyro

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Re: El cheapo amp scam!!!!
« Reply #22 on: October 06, 2015, 07:47:02 pm »
Might just be enough to fool your average HiFi magazine reviewer!  :palm:
Chris

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Offline jancumps

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Re: El cheapo amp scam!!!!
« Reply #23 on: October 06, 2015, 07:54:20 pm »
But why go through all this effort, and then not soldering the part?
It has the pins, the PCB has the traces. Everything is mounted - and then they don't solder it. It's almost more work than just soldering it in ?!#@@
 

Online Gyro

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Re: El cheapo amp scam!!!!
« Reply #24 on: October 06, 2015, 08:04:28 pm »
Those are fairly pricey output devices, the PCB was presumably originally designed to take them.
Chris

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