Need help debugging my TDA1557 amp.

[cepa]

Ok I built my TDA1557q amp Verstärker Schaltplan using the design from here. When I first plugged it in and only one channel worked, so I messed around a bit and got other channel working. YAY i thougth, but after a day of jamming that poor thing on MAX i noticed one thing, the speaker which didn't play at the beginning was playing slightly silenter. So I decided that I messed up again and built another one, same problems as with the first. Also one thing I noticed that the membrane (i don't know how to call it) on the bad channel is slightly higher than on normal working one.

Here is what i did
No bridges and the soldering is fine.
I cleaned the flux with acetone, and let everything dry/vapor off.
Used a bigger heatsink with fan.
Checked the plugs.

nothing helped.

[pacificblue]

Originally Posted by cepa

Also one thing I noticed that the membrane (i don't know how to call it) on the bad channel is slightly higher than on normal working one.

This sounds like DC at the output. Strange that it would happen on only one channel and on the same channel on two different amps. Due to the small number of components there is little you can do. Disconnect the speakers and measure the DC voltage at the output with and without C1 on both channels. According to the datasheet you will have to accept up to 250 mV of DC which is pretty high. The voltage at pin 12 should be half the supply voltage. Check whether that is the case with and without C1. If it is better without C1, skip it, because it is not in the datasheet either.

[cepa]

Ok, I'll test it tomorrow, because I don't currently have an access to a multimeter and I have WAY too much homework.

[cepa]

Yay, it worked, ThankYou