giving cpus a cb or killing them?

Hi Folks!

Been a bit frustrated so figured I'd post up and ask if anyone can help me figure out wtf is wrong over here.

With the last 3 chips (celery 430, e4700 and e8600) I've been getting only 1 cold run. Here's what I'm doing and observing:
1- quick air test with target cpu to ensure it posts
2- starting with dry mobo, tape the cpu in the socket (electrical tape, same process as I've been doing with other chips that haven't given me issues)
3- fill gaps inside the socket with eraser, gently close holdown
4- quick air test to ensure post
5- eraser top and around cpu holdown assembly
6- quick air test to ensure still posting
7- mount cascade evap to mobo/cpu and tighten it down- used to tighten it way down but have found that some cpus refuse to post if the cascade holdown's too tight...so been easing up a little
8- another quick air test- see above...sometimes fail to post if tightened down too much
9- start cascade, hit min temp, start system and bench like mad
10- shutdown system and cascade
11- 'the morning after'- used to work no problem (q6600, e8500). Quick air test, start cascade, let temp fall, start system and away we go BUT LATELY (and with the 3 chips mentioned above) the system posts warm but refuses to post cold. Thought maybe I was having condensation issues so added next/new step.
12- Tear down system, dry mobo, follow steps 1-8 again
13- System starts warm but not cold

Is it possible that I'm 'giving' the chips a coldbug??? Seems more likely that I'm damaging the chips when I have them up and running but it seems odd that everything is fine until that first shutdown after running cold.

Any ideas????? Driving me a bit crazy as it stinks to only get 1-3 subs out of any given chip

tia!!!

Sounds like CBB-cold boot bug I have a couple of P4's like that temps need to be no colder then -30c to -40c to boot(on my cpu's) it's a PITA saw some team members running some cpu's on air that I know have gone cold before thought they where being lazy found out the hard way why they where benching the cpu's on air

Thanks QF

Hmmm...have some definite cbb chips that won't boot at all cold but the 3 chips in my post ran fine at -105C for 1 session but after that they won't post cold.

Think I may have found my problem!!

For the current victim (e8400)...did the insulation in a slightly different way. This time, I didn't put extra eraser along the sides of the cpu inside the holdown (still have filled the gaps inside the holdown but just not as much eraser inside...will up pics sometime in the next days). Got my nice, long, cold run in on Sunday and shut down. System started right up last night so maybe I've got it.

Will do the erasering the same way for the next chips...if all that boot cold once then boot cold again without re-insulating then I'll report back and mark this thread as solved.

*Cough* Try my insulation method.... *Cough*

(Eraser gets cold, very cold. Insulation does not transfer cold as much, keeping the cold just on the CPU/socket. It might not help, but it's worth a try.)

hehe...thanks hokie, may give it a try.

The e8400 booted cold again last night. I think that putting too much eraser inside the socket was the problem. Will see how it goes with the next chip.