I have three Phoenix gold xenon amps in my system. they all used to work fine, but now my tweeter amp xenon 100.2 only turns on intermittently. it is wired to the same turn on lead as the other amps which turn on fine. i have tried using the turn on wire going to the other amps but same result. the bad amp only turns on about 20% of the time. Any ideas? I just had it repaired by Phoenix gold one month ago and it has worked great until this week. Any ideas folks?