Intermitant loss of sound on right channel

Question

This fault has been looked at by BBTOAST.
But no joy so far..he has told me to test with metre. comparing results with good left channel.
But because the fault is not permanent. wel its confusing?
I put amp on yesterday and the right channel had a little sound but very low. when i turn up the volume i get crackling in the speaker then all of a sudden the sound comes on, and works fine, after a bit it fades out
there must be a simple fault with this amp.
has anyone had simular fault..please help
thanks [e-mail]