My G/F's cousin's XBox is still here (yeah, I'm slow returning it --- but that's because he got a new one for X-Mas). When you initially power it up, either it gives no video/3 RROD (shutting it off and then right back on gives me the 2nd result here->) or it gives video/3 RROD but works.
After it runs for several minutes, if I power it down and then back on, the 3 RROD disappear. I suspect heat-related (both as to cause and as to solution). I used those bolts/nuts/metal and plastic washers and removed the clamps (yes, overheating it purposefully as per directions right before cranking it down tight), but it had no effect.