take several tries or warmup to boot

[ericjs]

I have a t420 that never boots cold. I need to turn it on and off several times...like say 8 or 12 times maybe to get it to boot. When it fails to boot the lights come on as normal, it hits the hard disk briefly and the dvd drive, and I hear the fan come on, but no boot screen. It is not just the monitor not coming on because when it boots for real, there is more hard disk access.

Once it is running, rebooting it never fails. It reboots fine every time once in a warmed up state.

Under the theory that there might be some kind of "warm up" effect going on, I've tried turning it on, and letting it sit in the non-booted but on state for a while before trying again. Sure enough it boots after I turn it off and on again without multiple tries.

Has anyone ever seen this before? Is there some particular component that could be fixed or would this simply be a motherboard thing?

[RealBlackStuff]

More likely your hard disk might have a problem.
Look on the HD manufacturer's website for a HD test-program.
Another thing to try: remove and reinsert both HD and CD-drive, could be just a bad contact...

[ericjs]

More likely your hard disk might have a problem.
Look on the HD manufacturer's website for a HD test-program.
Another thing to try: remove and reinsert both HD and CD-drive, could be just a bad contact...

I don't see how that makes any sense. Shouldn't the bios screen come up regardless? Even if the HD was completely missing?

When it does boot, I can hit F12 from the bios screen (or whatever it is called) and choose what device to boot from. So I don't see how any device failing should prevent it getting to that stage.

[Cigarguy]

Actually what RBS said makes perfect sense. Having dealt with a few failing HDDs in the past, I know that a failing HDD can cause BIOS not to post. Try what he suggested and report back what happens. If you are lucky, you've found your problem.

[rkawakami]

Other things to try if the HD is not the source of the problem:

- From a cold state, remove all hardware (memory, HD, Ultrabay), boot the system and see if you get the 1-3-3-1 beep code signifying no memory. If you do, that probably means the motherboard is okay. If you DON'T get the beep code, then the problem exists on the motherboard. It could be as simple as re-seating the CPU or there may be a temperature sensitive component on the board.
- Again, from a cold state, install one memory module (assuming there were two) and boot the system. If the laptop fails to boot or there's the 1-3-3-1 beep code, that module may be defective. If the T420 does boot, try the second module by itself. You should repeat this using both memory slots by themselves.

[ericjs]

I think I've ruled out the HD. I've tried booting with the HD (and DVD) removed and I get the same behavior...won't boot cold. After a warm up, I can get to the bios.

Thanks, rkawakami, I will try what you described.

[jayton4]

Have you flashed a BIOS update recently?

[ericjs]

I'm just finally getting back to this. Partly I procrastinated because it is a bit of a pain to get to both DIMMs on this laptop (I have 2 4Gig DIMMs, one is easily accessible through the panel in back, the other requires taking off the keyboard to get to. Partly I just didn't need to use this notebook for a while.

I started by pulling out the HD, the DVD and the easy to get to DIMM and tried rebooting. The BIOS screen came right up. So I added back the DIMM and tried again. Booted fine. Added everything back and it's fine. I have to assume it was just reseating that DIMM that resolved the problem. If the problem comes back I'll go through the whole process that rkawakami suggested.

Thanks to all for their suggestion!

Eric