No amplification The output transistors of my Pioneer VSX-D557 receiver located on the heat sink burned out. I need service manual to replace them, please. Kind regards, Javad

I rather suspect IC1 TDA7293 is the cause of your problem. If this is the case you will need to check the speaker/s

vsx405 came error dc protection chacked all power transistors c2500 ,a1948 all ok i was disconnect dc detector wire then ok after few minutes one pair burned with c945100 ohms resistors that time not fix heat sink then all replaced power on error overload with speaker and without speakers also coming error disconnect ol wire no chang pease help any expert amplifiers thanks

Without a Sams Photofact or a service manual I would go directly to the Power IC which is the largest Integrated Circuit mounted to a large heat sink. If you see any fuses they are probably for the power supply since any fused circuit on the speaker output would be ineffective because the IC would be damaged before the fuse would blow, but you need to check them anyway. Since the short was at the speaker output your problem should be at the final stage of amplification, which is the Power Amp IC. Prior to the early 70's you would have transistors mounted to a heat sink which could be individually checked and replaced. Then manufactures started to use the Power Amp IC which are more costly but eliminate having to find matched pair transistors. All you can check on the Power Amp IC is if you have an input using an oscilloscope or signal tracer and the power to the IC. If you have an input signal and power to the device with no output, I would replace the IC. Unless you have a test circuit for the IC you cannot test it completely unless you have a device like a Huntron Tracker or build a test circuit using a signal generator and a power supply to measure the gain of the IC with an oscilloscope. Short of ordering a service manual this is a good place to start.

Maybe you have MUTING selected. Turn the volume knob up or toggle the Mute control on the remote.

If it defaults to muting on power up find the manual and search it for a default volume setting.

I'd suspect a wild remote control or other I/R source in the area. Hide all the known remotes and block the I/R eyeball on the front of the receiver and see if it still happens.

It may seeem counter-intuitve but there are those who would love to have that ability.

You can always turn the speakers off while you're in the vicinity of the front panel plugging in the headphones.

Did you tell the Pioneer you HAVE a sub and run the test Tones for it and define hwo itr shares bass with the other speakers?

You can get fuses from any electronic parts shop, such as Maplin (UK) or Radio Shack (USA). I would get a few, because chances are the fuse did not just blow because of a bad speaker wire! Fuses are there to protect the device from an overload (which would cause a fire). The mostly likely cause of your fuse blowing is that your wire shorted out an output transistor on the channel the speaker was connected to and the transistor is acting like a piece of wire now!
If you have an Ohm meter I would put it's probes on the terminals of the transistors on the heat sink. You will soon know, as it will be just like you have touched the meter's probes together!

What kind ot TV?

Not sure what you mean by all signals.

Think about this: if your TV had any AUDIO capabilities that were superior to your REAL audio components, why would you need them?

The TV is the end of the line. Wouldn't it make more sense to get your TV-related audio as close to the source as possible? Your BD, DVD, cable and satellite all have high end audio outputs just begging for a place in the Pioneer.

sorry no easy solution as it sounds like the output transistors blew out or the emmitter resistors. you will need a service manual and an multimeter to measure the resistors on or around the audio output transistors they are a low value resistor usually around 1 to 2 watts in size. Do not replace any bad , burnt or discolloered resistors around the audio output transistors as if tou do you might just cause more damage to the output transistorsor audio output stage including the audio driver stage of the amp!!!!!!
Larry Dillon