Logic 4 channel amp IC identification needed

[barber02]

I have a Logic 4 channel amp on my work bench that has a blown IC on the bottom of the motherboard.

I have never seen the inside of one of these amps before and I have no clue as to what this IC is that is clearly toast. I am wondering if anyone has any information on these amps. The ICs are labeled on the board as U3 and U6. U3 has obviously seen better days. The ICs are mounted to the heat sink so I’d imagine that they typically run on the warm side and do a lot of work. They are connected across the rails.

Thanks in advance for any assistance,

David

 

[barber02]

Here is a photo of the top side of the board.

 

[Perry Babin]

The part number should be on the other side of it. Possibly a TDA8954TH.

 

[barber02]

Ok. Thanks Perry. I’ll pull it tomorrow. It’s getting late here.

 

[jkrokenberger]

Those are neat. Class D chip amps. I had an Eclipse EA 4200 that had similar. I never used it and sold it on as I prefer A/B but I did look at the board and saw similar components.

 

[barber02]

The part number you gave me Perry is correct. Thanks for your help. That chip went down hard and damaged some of the small traces and a couple of pads. I’ll work on fixing that issue as I wait for my chip to come in.

I ordered a couple of extra ones, as these chips are becoming obsolete. They are about 8 dollars a piece from mouser.

It looks like it can be a little power house for it’s size. The guy uses it on his motorcycle driving 4 full range speakers.

David

 

[barber02]

I replaced the TDA8954TH in the output section of this amp and a couple of resistors on the top side of the board that were out of tolerance.

When I power the amp up it goes through some checks and gives me 1 green LED blink followed by 5 rapid blinks of the red LED and sits there and repeating the error code.

This amp uses an SG3525 to drive the gates of the power supply mosfets and the chip has no power to it.

There is another chip close to the power and ground connection that looks like it will be the control chip but it has been masked off.

The manufacturing dating on this amp is 08-04-2012

Can anyone give me an idea of what this chip may be so I can look up the pin configuration for it?

Thanks for the help,
David

 

[Perry Babin]

The IC is like a PIC and the pin configuration won't tell you much since it's like a pile of lumber, it could be anything.

Does the owner's manual tell you what the protection code means?

 

[barber02]

I haven’t found one for this amp.

David

 

[Perry Babin]

Does any speaker output (bridging terminals if bridgeable) have a pulse of DC when powering up.

Will it try to power up through a limiter?