I have a Yamaha Electone HS-6 which for some reason won't power on anymore.. is there somewhere I can look at to get it fixed? where should I be looking at fixing this? Fuse? power box maybe?

It sounds like there may be an issue with the power supply to your Yamaha Electone HS5. Here are a few things you can try to troubleshoot the problem:

1. Check that the power cord is securely plugged into the back of the Electone and into a working outlet.
2. Make sure that the outlet you are using is functioning properly by plugging in another device to see if it powers on.
3. If the power cord and outlet seem to be working properly, try resetting the Electone by unplugging it from the wall and waiting a few minutes before plugging it back in.
4. If none of these steps help, there may be an issue with the power supply unit inside the Electone. In this case, it is recommended to have the instrument serviced by a qualified technician.

Chris, most likely yes, depending on the actual model. Best to contact Yamaha directly. Here's the link-
Contact Us Support Yamaha United States

Here's a link to one I think. Yamaha Electone HS4 Electric Organ

Looking for a Service Manual....any suggestions?

checked the internet and it states in the manual that if you do not use the organ for long time the user memory will be lost but the factory memeory will not be affected. check the below link:-
http://archive.org/stream/YamahaElectoneHsUsersGuide/YamahaHsUsersGuide_djvu.txt

I NEED WIRING DIAGRAM YAMAHA ELECTONE HS-4 (SCEMATIC ELEKTRONIK) PLEASE...TQ

First check if you get sound from the headphone jack.

Do you hear anything as the power comes on from the speakers..? A slight bump?

A lot of these dead audio things can be traced to a failure at the expression pedal. often these use a light dependent resistor and the illuminating lamp burns out. This is all down by the pedal.

Many of the Yamaha organs, including the FX20 I have, have circuitry that checks that the power amp has DC balance before a relay closes to connect the speaker. A failure in the amp can cause dead sound as well.

the problem is the main output amp. It is an IC so it is better left to a tech to put it in. Just had the same problem with mine. Seems to happen when unit is left on overnight.

j have had the some problem on hs 7 . The relè not work probably you have a cold o breaked joint on power amplify integrate or it is broken.