TDA2009 Bridge Amplifier Problem

[amcintyre95]

Hi, I'm a tech student but not great at electronics. I'm making an audio amplifier using a TDA2009 chip, and I'm using the '10W + 10W Bridge Amplifier' circuit (schematic in attachments):

I have successfully breadboarded this circuit from this schematic and using my own circuit diagram (see attachments), and the audio is great when using the breadboard. But when I then duplicated the circuit onto a PCB for some reason it does not.

As far as I can tell the circuits are exactly the same and I (and my teachers) have double checked the components multiple times, but none of us can figure out why it doesn't work.
The speaker is quiet and crackly but you can just about hear faint music in the background, also the TDA2009 chip gets burning hot, even why I use a heat sink on it - none of this happens with the breadboarded circuit.


I have included an image of my PCB layout in the attachments and I am using a 30W, 8Ohm speaker (link below) with a 12V power supply.

http://www.faitalpro.com/en/products/LF_Loudspeakers/product_details/?id=401005150

I hope this all makes sense and thankyou in advance to anyone that can help me. Alex.

P.S. Please ignore some of the badly drawn capacitor symbols in my circuit diagram there obviously shouldn't be lines going through them.

 

[Arouse1973]

Can't see any connection issue. But what is the blue connection running between the amp? is this a wire link underneath the PCB or a PCB track? It looks quite long for the feedback connection.
Adam

 

[davenn]

hi there

welcome to the forums

I deleted your homework section copy of this thread
its not really homework in the strict sense
and also the other post try and not post multiple times in multiple sections
it only causes lots of confusion

show us photos of your actual construction
sharp and well lit and both sides of the board

cheers
Dave

 

[KrisBlueNZ]

The PCB looks OK to me as well. I would also avoid the long track under the IC if your PCB doesn't have a solder mask, because of the risk of a solder short to it.

Check carefully for solder bridges (you can scrub the underside with a toothbrush and isopropyl alcohol). If that doesn't fix it, my guess would be that the TDA2009A on the PCB has been damaged.

 

[amcintyre95]

Hi, thanks for helping out with this

The blue connection is a wire link joining the 1K resistor to pin 10 ( I thought a track might be a bit risky too )

Thanks davenn sorry yeh I'll just stick to this one from now on + I'll upload the pics asap.

Speaking to my teacher he's said that schematics like the one I'm using sometimes have mistakes and from a bit of research it looks like a few people have had the same trouble as me before with this chip. Could that maybe be the problem?

The weird thing is my breadboarded circuit works fine but they're both from the same schematic - I'll try and upload a pic of my breadboard too but it's a bit messy.

 

[davenn]

Speaking to my teacher he's said that schematics like the one I'm using sometimes have mistakes and from a bit of research it looks like a few people have had the same trouble as me before with this chip. Could that maybe be the problem?

The weird thing is my breadboarded circuit works fine but they're both from the same schematic - I'll try and upload a pic of my breadboard too but it's a bit messy.

well that speaks for itself

if OK on BB and not in PCB then there's a wiring error in construction

Im actually wondering if you have reversed the chip on the PCB. Power going to the wrong places will heat things up

cheers
Dave

 

[amcintyre95]

Here's the pics of my PCB - I've checked a few times and there are no tracks touching so must be an error with the layout maybe?

If you need I can take a few pics of my working breadboard.

 

[davenn]

hi ya

I don't see any obvious problems, your construction is very clean and tidy
maybe at some stage you reversed the power to the board and damaged the IC
and hence now why it is heating up ?

Dave

 

[Sergey]

This datasheet of 2009. Chip in the middle of the board is no longer correct (personal opinion). Sorry for my english

 

[Sergey]

link to datasheet
datasheet.octopart.com/TDA2009A-STMicroelectronics-datasheet-14135700.pdf

 

[davenn]

Hi Sergey

what specifically did you think was wrong whith his construction ?

Dave