I don't like giving this advice but I am afraid that your curiosity might push you forward to touch something you are not aware of so I will start off with DANGER DANGER DANGER First I say take it to a service tech or call the company, but if you are wanting to know more, proceed to read on,
There can be other means of grounding, such as a grounding plate or you might see a bare copper wire or green wire, can be Red, Black White and copper or you might just see Red, Black and White with a grounding plate installed, But use extreme caution, if you decide to go poking around in there, be sure to KEEP ONE HAND IN YOUR POCKET, preferable back pocket at all times so your body doesn't complete a circuit.
Basically everything electrical is wired for 240, we here in America just half stepped off the transformer thus we get 120 volts, on 240 you can touch the red, touch the black, even the red and black together and basically nothing, but if you hold the WHITE NEUTRAL(DANGER) wire and touch any other color you will face severe electrical shock or even death so stay away from it is the best advice I can give you, but if you must look around to clear your uncertain feelings, do it unplugged and see if you see there's wires passing through a plated surface first and look for a green or plain copper in the area, just remember keep one hand in your pocket , I mean don't even touch the chassis or you could become the ground wire, even while it is unplugged because unless you have a way to discharge a Capacitor it can hold charge for days and ZAPP! YOU CAN STILL GET SHOCKED even unplugged. look first at the actual cable coming in from the plug and see how many wires there are then trace from there to the transformer and follow with your eyes to see where they go, Please USE EXTREME CAUTION I can't express this enough and have a friend present with you, it's a great learning experience but you have to respect the power you are dealing with at all times, you can email direct if you need further assistance regarding your findings,
good luck and always remember when dealing with electricity anything with 240 transformers and tube circuits will take you from this world fast if you touch the wrong things in there and we don't want to start wondering where Georgie boy is that we haven't seen him post in a while stuff!
