20 Most Recent Crown XTi 4000 Amplifier Questions & Answers

Power supply likely failed. Electrolytics are the primary culprit.It should have a switchmode power supply, so it is lmost likely the 5 volt section failed.

The fuses are on the inside

Schematics are easy to find, just enter: schematic crown it4000 in the Google search engine. I cannot find any semantic

the other is defective?

details? what is short1?

the fans on these amps are heat sensitive, only when the amp heats up, then they come on

If you're using a microphone it's feedback, duh.
How to Eliminate Feedback
http://www.mediacollege.com/audio/howto/feedback.html

Hiya, to unlock press PREV and NEXT until it says unlocked.

The short 1 sounds a little serious though. Have you tried taking off the speakers?? If still there then suggest contacting crown. They have a pretty good no nonsense 3 year warranty

Best of luck

Switch off the amplifier for some time and allow it to reset. disconnect the speakers and reduce the volume level before you put it on. If the power does not come on you will need to probe inside. Get help if you are not familiar but check on the power lines coming in for failure of fuse, the secondary power supply section transformer or the smps power. Hope it would not go further to this but check this out.Check for shorting inthe outputs, if so disconnect and test. Good day