This is a generic answer for this kind of question.
When there is no sound
Check the obvious.
Is there a light on the organ indicating it is on?
Sometimes a sustain pedal plugged into a volume pedal socket will mute the output, check this.
Headphones out, most headphones will turn speakers off, sometimes the headphone switch can be dodgy, work the headphone plug in an out a few times
- Plug it in to a known working wall socket, switch on at the wall
- Switch on at the organ, check light
- Very old keyboards need a voice to be selected!!
- Turn master volume up
- Turn any other volumes up
- i.e. lower manual volume
- upper manual volume
- swell pedals down
There maybe a switch that turns off the speakers, look near the output sockets
Software volumes up, check display, if any.
MIDI instruments, check local control is ON
Still no sound?
Can you hear anything from the speakers?
Hiss or hum usually means the speaker is ok
Total silence may indicate speaker failure, but only if there is one speaker, as in older home organs, or smaller keyboards
Try headphones next, TURN Down master volume first just in case!
If there is some sound, very quiet and gross distortion then possible power amplifier failure.
If your instrument has any kind of line out as well as a headphone jack, try these.
The line output will likely be a pair of phono sockets,like you have on HiFi equipment, 1/4 inch, 6.35mm jacks, like the bigger headphone connector, a 3.5mm socket like the smaller headphone connector, or even a DIN connector on older equipment.
Connect these to the aux (or Line or CD) input on your HiFi, guitar amp or similar. (some times these outputs will drive headphones, usually you will only hear anything in the left side). If this works then it is very likely the power amplifier.
Further tests on MIDI equipped keyboards would be to see if the MIDI does anything.
If MIDI out works and there is no sound, and MIDI in makes a sound this points to local being off, buried somewhere in the menu will be local on or off, make sure it is on.
If MIDI out doesn't work then the failure is likely to be internal power supply or something else critical (not nnecessarily major).
Power amplifier failures in newer, low power, keyboards are often the power amplifier chips (i.c,s), older amplifiers may have just blown their fuses but one or more output transistors may have failed.
Cost of repair will be down to the time it takes to get to the fault, taking these to bits and putting them back can take a lot longer than the repair.!
Hope this helps, Chris the Fader