Help with tda2005 amp circuit

[pgodfrin]

Howdy,
Etched a pcb from xtronic.org for a 20w amp from a tda2005. It actually works, although with hard strumming or a hotter signal, it just cuts out. I think the chip has some builtin circuit protection, but as an electronic nitwit, I have no clue how to troubleshoot it.
Can anyone give me a hand?
phil