Is there battery for the memory backup in the Electone HC-4 organ? If so, where is it?

There are two.
STK4152-2 and STK4192-2

Service Manual for sale on eBay

ttps://www.ebay.com/itm/Yamaha-Electone-Keyboard-HC-2-HC-4-Service-Manual-Schematics-Parts-List-OEM/302676480589?hash=item4678ec924d:g:iToAAOxynwlTcjai

Yamaha Electone Keyboard HC 2 HC 4 Service Manual Schematics Parts List...

Retrevo has a link to the manual for the Yamaha Electone HC-2 organ here: http://www.retrevo.com/search/v2/jsp/downloadPage.jsp?doc=42cf1723b6ae869802a215f20e1c7dc1&modelid=961462&q=Yamaha+HC-2 . You will need to enter a code to access the manual. You can check if Yamaha has copies for sale. You can also download the manual from the Yamaha downloads page: http://download.yamaha.com/top/?site=usa.yamaha.com&language=en . Just search for the HC-2.

I hope this helps.

Cindy Wells

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

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

You can find the pdf user manual for the Yamaha Electone HC-4 HERE.

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

Go to the electone forum at electone.com and ask there.

Also the organ forum

http://organforum.com/forums/forumdisplay.php

When there, go into the home organ section.

Check if you may have knocked off the speaker leads OR ones to an expression pedal.

Have you tried joining at the Electone Zone at www.electone.com? It looks like a fun site and its free to join. Maybe one of the members there can kindly help you.