Mitsubishi model ws65819
the green color goes off after a few moments.
Open her up and see if you have a bad ground connection, or a bad connection on the CRT boards. If it's not that, your green CRT may be bad, and could cost a pretty penny. Usually, if you replace one, it's best to replace them all for proper grayscale tracking.
But, it might not even be any of those issues...I'm no expert on TVs, so don't take my word for it. Best to call a pro repairman. If you do decide to tinker around inside, this service manual should help you out a lot.