Let me see what I can find out for you, I'll be back in a few minutes.
Great, that info helps.
When you get the back off, remove the CRT drive card from the end of the tube. If you gently wiggle it, it should just come off. Make sure it can't short against anything.
Now turn the set on and see if it will stay on. If it does, I'm afraid you have a bad picture tube.
If it still shuts off with 5 blinks, look on the large board on the bottom and find the set of leads that go to the CRT drive card. They should lead to a 9 pin connector on this board labeled CN303 (there may be connector CN705 on the drive card, and if that comes off, that's fine to use that connector). Now try the power again, and see if it stays on. If so, you have a defective video output amp IC on that board.
Try that and let me know!