My Rotel 1520 Goes into Protection Mode...

[PeterM]

My Rotel RA-1520 power amp goes into protection mode when I turn it on. I think this may have to do with my dog stepping on my speaker cables and loosening them while the amp was on thereby shorting the output of the amp when on. The strange thing is that when I took the Rotel into a shop today to see about fixing it, the salesperson hooked up the Rotel to a cd player and some very small speakers, and the amp worked just fine! So I went home, switched out the cables, connected both speakers, then one alone, then the other, and the protection mode came on almost immediately. Music would play on cd and turntable, but just for a few second before cutting out and then starting again briefly, then cutting out again. I also connected my Rotel to some bookshelf PSBs and it went into protection mode. Any ideas here about why the Rotel would work in one situation but not the others? Something to do with impedance? Any advice would be appreciated.

 

[lovinthehd]

If you used new speaker cables and different speakers and it didn't do it for the shop's test....something odd/wrong with your electrical supply? Try other outlets in your house perhaps?

 

[PeterM]

Thanks for the suggestion. I moved since first having this problem so I don't think it's the outlets or house!

 

[highfigh]

Thanks for the suggestion. I moved since first having this problem so I don't think it's the outlets or house!

Does it go into protection with no speaker wires attached?

 

[PeterM]

No, it doesn't. So I connected one speaker to the second set of outs from the amp and all is fine. Changed to the other speaker and protection comes on! So I figure now that it's one channel in the amp that is the problem. So just to verify this I reconnected the speakers to the first set of outs on the amp, one speaker at a time, and now no protection comes on, even though I haven't changed anything since the problem began! For the past half an hour all is fine. Something reset? Who knows. Anyways, on we go, the music is playing again!

 

[PeterM]

And now...back into Protection mode.

 

[TLS Guy]

And now...back into Protection mode.

Sounds like a bad power transistor causing DC offset when under load and triggering protection. It is just possible that you have a speaker that has been over driven and has shorted turns in the voice coil. Check the DC resistance of both speakers with a multimeter and see if they are different.

 

[PeterM]

Sounds like a bad power transistor causing DC offset when under load and triggering protection. It is just possible that you have a speaker that has been over driven and has shorted turns in the voice coil. Check the DC resistance of both speakers with a multimeter and see if they are different.

Sounds about right. I took the amp into a local store for service. Should know what's what in a week. or two.

 

[TLS Guy]

Sounds about right. I took the amp into a local store for service. Should know what's what in a week. or two.

Make sure you check your speakers like I suggested before hooking the unit back up, otherwise you might end up where you started.

 

[PeterM]

I have a DenonAVR connected to the same speakers and it works fine.