WHAT TYPE OF TRANSISTOR Q1 ON THE BOARD NEXT TO THE SYSTEM CONNECTOR

Try to find a new board. Trust me, you are not going to fix it - there is a reason the traces and board are showing burn marks. Either scrap it or just buy another one. If you toss it cut the power cord off next to the chassis.

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

Step 1:
Check the setting of LOCAL CONTROL in GLOBAL mode.
Go to GLOBAL mode page 1 (Figure 1-2):

Move the cursor from the MASTER TUNE to LOCAL CONTROL. Setting LocalControl should be in the ON position.
When the setting is OFF,set it to ON (use dial TEMPO / VALUE or DOWN / UP button).
Go back to ARR or PROG mode,and play the key to check audio.

Step 2:
If in step 1, the sound still does not exist, then it is a hardware problems, and the possibilities are :
Figure 3, the section in red shading is a block may be damaged.

Figure 4 is a scheme. Parts that might be damaged in case of no-audio are:
IC 2,4,5 (4570), IC9 (78L05), IC6 (PCM69AU), IC 3 (5216).
Check also the transistors Q1-Q7 (This is the MUTE transistor, and this is most often the cause in case of no-audio).
If you can not fix it by yourself, then leave it to the experts.
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I you mean the sustain type pedals, FIRST check the connector(s) as they often come loose or unseated. Next check for a broken pin in the connectors. It is UNLIKELY you could troubleshoot anything inside with just a meter. It appears that some of the Roland pedals receive 5 volts in the connector, and upon contact closure the voltage is sent back to the piano where it drives C4570 buffers with 680K to ground and an RF bypass cap and series 330 ohm to the + of the C4570's. The circuit I have is for a different piano but if yours uses the 8 pin connector it is likely the same.
The contact is actually optical interrupter modules with a driver transistor. There are threshold setting pots in the pedal assembly as well. The farthest I would suggest you go is to make sure the optical interrupter modules are free of dust if this is the type you have,.

I don't have a exact schematic for your amp, but I can give you some hints and suggestions...

USUALLY when the output transistors fuse there is a problem at least one level back and sometimes two levels. Often the driver transistors also get fried and sometimes one stage farther where the bias is regulated for the final amp transistors. A schematic is imperative to diagnose and repair unless one replaces every part.

Next, to prevent damage when restarting the amp, put a 100 Watt incandescent lamp in series with the hot power into the unit. This acts as a current limiter and auto-resetting fuse. The lamp will come on and limit the current while one troubleshoots the amp to find what is causing the current drain.

This schematic MIGHT be pretty close to your unit:

http://elektrotanya.com/swr_swr2000_power_amp_module_sch.pdf/download.html

I would expect to see Q4 through Q12 destroyed and maybe a few more components. If transistor Q4 opens, goodbye all the transistors! The 1N4004 diodes are PROBABLY big enough to take it, but all the small transistors probably are damaged or degraded... The high value resistors will survive, but the low ohm ones that can draw enough current may be damaged.

Try to analyze what each part of the circuit is for... I think Q13 and Q14 are part of a soft start circuit. This amp is NOT well protected in case of component failure and MANY that fail in the final stages cause catastrophic destruction.

Use my suggestion for the lamp. Often using a Variac to slowly bring up the voltage is handy, but one doesn't only have one available.

Usual problem is the Channel A amplifier has burned and blown the switching transistors. Usually an internal board arc occurs and unless very skilled at board work of clearing the burned area and replacing the components you are better to replace the HCA2400 amplifier module... about $160

They are NOT called motherboards, just circuit boards.

Sometimes the board can be restored by carving out the black and re-insulating it and repairing the cause and bad components.

Likely the power transistors have shorted that are associated with that side and burned compnents.

Many shops will only replace the whole board rather than do the labor to restore the board... Yes, either way it will be expensive to repair.

Causes of these failures can be overdriving the amp. bad speakers and or cables. Loose speaker connectors that vibrate can lead to this.

Another problem can be if SUPERSONIC (can't hear it) feedback is occuring at high frequencies that overloads the amp.

If the fuse blew do NOT replace it till the unit is serviced or you will burn up more components. These units will blow out from a minimum of three to 30 components when they blow.

There is weak insulation between layers of the power amp circuit board and the arcing destroys a minimum of three transistors and often many more components on the power supply board as well.

I have repaired several of these and it is a lot of work. The power amp module can be had for about $175 but it often takes out the power supply as well.

Go to Peavey's website

http://www.peavey.com

You may find what you are looking for here if not you may have to call them.