TDA2050 keeps blowing...

[noddyspuncture]

Hi Guys,

I've been doing quite well recently with my repairs, but one has just got me stumped so I thought I'd run it past you here. Maybe someone can shed some light...?

I am trying to fix a small fender practice amp that uses a TDA2050 amplifier IC/transistor.

It's getting so that I am wondering if it is worth spending any more time/expense on the thing.

I changed this component 4 times now. Each time I fire it up, check voltages then connect speaker etc.... and it works perfectly! For a while... but then, all of a sudden - *pop* and it starts humming or whatever...

The output leg (pin 4) gets shorted (or very low resistance) to one of the power rails. Everything (there's not a lot) around the IC checks out fine. It is a "Fender Frontman 15R" - I've attached the schematic.

Cheers,
Tom

[tonyharker]

Are you sure your replacements are not fakes?

[noddyspuncture]

Thanks for the reply.

Aha... OK.
Well, they were bought from China - you think that might be the problem...?
I suppose this could be common?

Cheers,
Tom

Are you sure your replacements are not fakes?

[tonyharker]

Can you break one of the failed ones and post a picture on here?

[noddyspuncture]

Yes, sure I can... when you say 'break' - just exactly how do you mean please...?

Cheers,
Tom

Can you break one of the failed ones and post a picture on here?

[J M Fahey]

TDA2050 stoopped production, last 1000 (legitimate) ones were swept from Mouser, no kidding so now it's big business to fake them.

Usually relabelling TDA2030 which are still in production, although handle only half as much.

Left 2030 , rigtht 2050 :



You may separate plastic from metal by nipping one corner of the union with the tip of sharp wirecutters.

To solve your problem TODAY, get LM1875 from Mouser, they are pin compatible, original, and still in production.

Don't waste money on anything else.

If you will use them in the future, buy a couple spares.

http://www.diyaudio.com/forums/chip-amps/264071-counterfeit-ic-die-revealed.html

FORGET EBay , period.

[noddyspuncture]

Thank You guys, for all the help and advice...!

Cheers,
Tom

[noddyspuncture]

Well it looks to me that your were right... mine actually seems a bit smaller.
I attached a couple of photos...

So I was duped..! At least I now know...
Cheers,
Tom

[Roly]

Good work!   :dbtu:

So I was duped..!

Yeah, but that's not your fault.   :trouble

I've bought a bunch of Arduinos and shields for LCD, SD card, barometric sensor, and various LED's, direct from China and I haven't had a problem yet, all arrives and works as it should, but if we are buying such el-cheapos then it's a bit of a gamble and we must expect to lose sometimes.

But when you pay a reputable supplier full-fare for something it's reasonable to expect it to be at least authentic.

Sadly if you decide to avoid chipamps and go transistors you are no better off, particularly with very high power transistors, big FET's, and the like, high unit value.

[noddyspuncture]

Many thanks for all the input folks...

I filed an 'unhappy claim' on eBay for these IC's... just in principle - they were after all, only a few dollars.

Today I got a refund...!

Cheers,
Tom

[J M Fahey]

Cool.

Incredibly, yours looks exactly like the TDA2030 chip posted in the other Forum, down to the etched square around it.

As of varying success rate using EBay: anything that is in massive current production (such as those Arduino, LM3886 spare and on kits, etc.) it's reasonably that you'll get the good ones, or at least good "second brand" ones ; but anybody looking for obsolete/not produced/hard to find parts thinking they will find them in China and at low price to boot, is expecting too much.