My amp states overload protection and no sound from both front speakers but all other speakers are working

What is the speaker load in Ohms that you are running? Or what exactly is hooked up to it? are you bridging it? The protection light will come on if the load is too much for the amp to handel. If the load (in Ohms) is less than the rated load that it can run, it will stop the output to keep the amp from self destructing. The amp will sense that the demand for power will be too high for the amps circuitry which will either make the amp get so hot that it will burn up the copper on the board or more likely burn up the power mosfetts that power the speakers. If the Ohms are within range then it will allow power to flow through the circuit until the rails that the mosfetts are bound to until they get so hot that it will go into thermal protection. So if your amp has both thermal and overload protection lights and the overload is light then the load is probably too much for the amp. if it's bridged in mono the you can only have 1 speaker setup hooked up it if it's a 2 channel amp. a 4 channel amp bridged in mono for both front and rear channels will be able to have 2 speakers rated a 4 ohms each hooked up to the amp 1 set per bridged output or channel.
Try it running in stereo with only 1 speaker per channel and see if it will produce sound. If not then you have an amp that has internal problems and will need to be serviced. Check your warranty to see if you are covered.

here is your guide:

http://www.fixya.com/support/t13907270-sony_str_de925_stuck_in_protect_mode

Note : output transistors are embedded inside the Hybrid IC

on some models.

I'd suggest you try the basic speaker setup routine with tones to be sure all speakers work and none are shorted.

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on; or it may turn on but produce no audio to the speakers.

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 'nekkid'. 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.

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

Overload is another form of protect mode. See the link below for an explanation of protect. Also, in your specific case, the problem is definately internal to the amp rather than an external cause. Expect a parts cost in the $40 range. Feel free to post additional questions.
Thanks,
Dan

Link: http://www.fixya.com/support/r5390728-protector_means

Sounds like you are running your subs at to low of ohm. Amps are rated differently on the levels of ohms or resistance that they can get to. If you have a dual 4ohm sub and run it in pairrell it will drop to 2ohm and if you run the same sub in series it will be 8ohm. Your amp will go into protection if the ohm is to low.

-david

Disconnect all speaker connections and rca cables. Leave power, ground and remote wires intact. Try turning on again. If you still have a protection light your amp is faulty. Sounds like you are overloading the amp. Please check speakers impedance. .A thumbs up would be greatly appreciated if this answer is helpful to you

I assume these are the complimentary pair that drive the speakers. On one of the speaker. You know I think you have a short in the speaker that it drives. Speaker can fuction even if there was a problem with it. I think what happened is when the original transistors shorted out it overloaded the speaker, but not to a point where it is burnt. There is nothing that can overload a power transistor except the speakers, I design a lot of amplifiers, the base input can overload it if you put dc in there, but that would make a the sound all distorted, I assume the sound seem fine. Solution is try connecting a known good speaker and I bet it wont burn out anymore. Even if the speaker look fine don't trust it.

Your speakers may be underpowered by your receiver. Check the watts and impedance of the speakers, and the wattage of your receiver to make sure they closely match. (impedance is calculated in ohms- indicated by an omega symbol written near the wattage rating)
"Overload" may also mean that the amp went into protect mode, and that means that you're OVER-powering your speakers and it wants to protect them from damage due to impedance mismatch.
But- if the impedance and wattage match between the speaker and the receiver/amp, you should check the polarity of the speaker cables (+/-) BTW- never put 2 speakers in 1 output- that will almost always cause something like this and will sound bad.
I hope this helps.

Check the speakers impedance. it should be greater then 6ohm otherwise you overload the system. Also, if the speaker sytem is rated (in Watts) below the amplifier's power it overloads the amp at higher volumes.

If the amp still goes into protect mode, the easiest thing to do is disconnect the RCA cables from the amp and see if still goes into protect mode (after turning off/on). If it does, the issue lies in the amp or the wiring to/from the amp (most likely case). Check to make sure no speaker wires came loose and touched +12V or ground (car body). From the sound of it, my guess is something internal to the amp died and will need repair.