Are my two TDA1562 destroyed??

[newbadboy]

Many years ago i tried to build a car amplifier based on two TDA1562 amps. For some reason i gave up and i dont exactly remember why.

Couple a days ago a found the kits and gave it a try. It doesn't work. I will describe the symptoms and hope that u guys can give me some ideas what it can be or if they are destroyed. The pcb's are printed after an article in Elektor så it's probably not caused by bad routing or so.

First i can say that i have two chips mounted on two different pcb and they both behave exactly the same.

If the chip is disabled by the mode pin the current drwan from the power box is zero. So this is OK
When i enable the chip by putting the mode pin high the current goes up to 120mA (without input signal). I guess this is ok also.

I tried then feeding it with a music signal from a mp3 players headphone connection. No sound out. Connected a tonegenerator and sinewave 1kHz. It was still quiet. Not until i raised the input voltage to a couple of volts i could hear a loud signal to the speakers. If i decreased the input signal then output signal also decreased. If i increased it "worked", but now the chip was consuming about 1,5A even with no input signal. The only way to stop the high current consumption was by pulling the mode pin low. When i got sound out the diagnostic pin went high.

If i have enabled the chip there is about 2VDC on the speaker output pins relative to ground. When i manage to get sound out to the speakers this dc voltage level goes up to 10VDC .

I checked the output with a scope. There is no oscillation or such. The output signal is clipping on the positiv "top" regardles if the input signal is to high or at good level.

Are my chips dead and need to be buried???

[Tekko]

Reat the datasheet! These are btl amplifiers, not stereo amplifiers, so your output to ground measurement means nothing.

You should hook the speaker between the "channels" on one ic.

[newbadboy]

Actually i did put the speaker on the speaker outputs and not to ground so they are correctly connected.

Then it's my measurement with ground as reference that can't be trusted,

but the other symptoms are correct.