What kind a outputs transistor use a QSC Gx3 power Amp

You have a high power amplifier and the work you propose leaves no room for either error or compromise. If, as you suppose, the output is by complementary pair, the transistors must be matched pairs providing equal gain characteristics.

Unless you have seen inside a complete amplifier of the type you are only guessing at the output stage(s) that could be by module or a multiple transistor output. There also might be other driver stage(s) sharing the same heat sink.

The least you will need is a service manual and an internet search produced a number of results on the below link.

https://www.google.co.uk/search?rlz=1C1CAFB_enGB673GB676&ei=PtG_W56NM6mIgAaYwaqIDg&q=qsc+mx1500a+service+manual&oq=qsc+MX+1500a+amplifier&gs_l=psy-ab.1.3.0i71k1l8.0.0.0.32505.0.0.0.0.0.0.0.0..0.0....0...1..64.psy-ab..0.0.0....0.D6yNqkAW5nw

Are you then saying you have no sound, yet the amp is on? If so, with the unit off, listen carefully to the top of the amp. When you first push the power button, you should hear one click, followed by another click, about 5-20 seconds later. I'm guessing you hear the first click, but not the second. Is that correct? If this is correct, and you are interested in having your QSC repaired, Please visit my website at audioserviceclinic.com. You may contact me there. Thank you.

Check the triac that is at the output

Check for shorted speakers, if ok check output transistors for short

For QSC amps the GX series are not bridgeable. You will have to run one speaker to each channel.

Register and download the manual for free at retrevo.com

http://www.retrevo.com/support/QSC-GX3-Amps-manual/id/23107ag606/t/2/

See page 7.

"CLIP: red, to the left of each Gain control.

Normal indication: illuminates whenever the amplifier is driven beyond full power. The LED's brightness indicates the amount of distortion. Distortion that causes only brief flashing may not be audible.

During muting, the indicator fully illuminates. This occurs during normal "On-Off

It is likely that additional components were damaged when the output transistors (2SC5200, 2SA1943) were shorted. Check the driver transistors which preceed the outputs in the circuit as well as resistors in the area. Also, there should be a bias transistor mounted on the heat sink that needs to be checked as well.

Keep us posted,
Dan

You should check the speaker set, maybe it's short circuit.
Try remove the speaker set from the unit, than switch on the amplifier again, if the red light still on, surely the final drive is damages( Transistors or IC's).
Replace it with new ones.

This is a very precise questions as QSC amp are pretty rare and high end electronics equipment. There is no way getting an answer other than getting the amp at a sound shop for repair, wich might go for a visit at QSC anyway. From a sound shop repairman...

If the service manual is not available on the JVC websites then you should just Google search "JVC A-GX3 service manual" There are many websites that archive manuals. You'll probably have to pay for a copy. Why can't you disassemble the unit and see the output transistor numbers first? More importantly how do you know this is the fault?