QRZ.com, eham.net and forums.radioreference.com come to mind immediately. If you need the manual you can find it at http://l-36.com/manuals/Icom-IC-735.pdf, the service manual at http://www.fujiyachts.net/manuals/Icom%20IC-735%20Service%20Manual.pdf. There's a list of common service questions at http://www.qsl.net/icom/oldicomfaq/ic-735.html.

What's going on with it?