Protect light comes on when power on - Fender Passport Deluxe 500watt Sound System with Deluxe Speaker Array

Take it to the repair shop. Something is blown.

Do the protect lights light up when you turn it on? There is a soft start circuit that should delay for about 3 seconds when powering it up, it sounds as if this is not working. If you don't get the protect lights for a second or so when turning it on then this has failed and you need to get it serviced and repaired before more goes wrong.

The most likely case is that one of the main output transistors (if which there are many) is shorted. When the protect circuit senses DC on the final output, it will not allow the output relay to come on to protect the speakers from raw DC. With the power removed, you can check between each outputs Emitter and Collector and you will probably find close to zero ohms. From that point you need to unsolder each of the pins of the bad channel until you find the shorted device(s) and replace them.

The protect light generally comes on when the is a short in the speaker cabling. as a test, turn on the mixer without any speakers hooked up. If it still goes into protect mode the problem is in the mixer. Take it to your local music store and have their tech look at it. if it doesn't go into protect, check the speaker cables by plugging them in one at a time. The bad one will send it into protect.

good luck

The limiter probably delayed the eventual damage. Nothing prevents all damage absolutely.

Generally speaking, an amp protects itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech for forensics and further action.

Check for loose speaker connections at the speaker as a root cause for intermittent shutdown.

Likely an overload failure caused the protect light to come on, and then the fuse blew so all power is off... Do NOT replace the fuse as you will LIKELY do additional damage to components. Take unit in for repair immediately.
Note: These units are really hard to work on due to the way they are packaged.

Either one of the amps or the power supply has blown. The protect light means the power supply has been shut down due to overcurrent. Take unit in for repair. These are hard to work on due to packaging.

Likely there is either a failure in one of the power amps or the power supply. The protect means excess current is being sensed.

You need to take in for repair... these are really hard to work on due to the packaging.

Go to http://peavey.com/support/searchmanuals/archived.cfm Their main site also has info. DDT is an active compression feature to protect the product .

The protect circuit is activated by a current sensing transformer in the *input* of the power supply. If any of the subassemblies of the unit (or all of them in combination) draw excess current then the protect light will illuminate and the power supply shut down to prevent any damage to the system.

The circuitry in the power supply is fairly robust as well as fuse protected so it is unlikely that the power supply itself has failed. More than likely one of your output power transistors has been shorted and it is easy to check this yourself if you are interested in doing so.

Furthermore if you follow a few *simple* precautions you can do this safely and confidently.

Post again on this thread if you are interested and I will spew the details.

-BK