ZT3340US - Power on problem

I searched the forum for the topic and found a few posts on power on problem... most of which were about dv9000 but none quite matched in description to what I am experiencing. Here's what's happening with my ZT3340US:

1. Battery in, ac power in, press start switch - nothing.
2. Leave battery in, ac power in for about 45 mins, press start switch - the pc lights up, hard disc LED flashes 3 times, hard drive gears up, but then all of a sudden even before I see the HP splash logo on the screen (ie in 3-4 secs), I hear HDD shutting down sound... as if someone drained the power out - or the sound that you hear when you shut the system down (not the Windows wav, but the HDD shutdown sound).
3. Keep trying to power on, lights keep coming up ev time, but go away in 2-3 secs.
4. Twice in the past three days, leaving the pc for another few hours like that and then trying to power on worked and pc booted up as if nothing was wrong, and it ran perfectly fine until I shut it down. But after I shut it last afternoon, it has not powered up since.

I have already tried the following - these didn't make a difference:

1. Drained the capacitors.
2. Remove and re insert the memory module and hdd.

Something that I don't understand:
The first time pc refused to power up, it had only 45% battery left... finally when it did power up, the battery charged to full. Later, I shut it down and restarted later without a prob... at that time, I did not have the AC power plugged in. However, if I remove the battery and put the pc only on AC power, I don't even see the power LED light up - though it lights up fine with the battery in and AC power plugged in. Does it not mean that the battery is okay? And so is the power adapter, cuz otherwise how would the battery get charged?

Any help troubleshooting is appreciated... I just bought a DV6149US, cuz I needed to give ZT3340 to my brother, and now its not working and I don't know what to do

Thanks,

 

It sounds like the power connector on the motherboard is coming loose and providing almost no power at all...that was a common problem with that series (as well as the other series of notebooks sold during that time).

If you have a warranty on that machine that is still active, you'll probably need to start making some calls and have someone solder it back together for you.

 

Thanks for your reply... may be you're right. That's what happened to my last HP. The power connector went loose - but that was easy to diagnose, because occasionally the battery LED would go orange even though the power was plugged in... noticing this, I would fiddle a little with the power connector and it would restart charging. In fact it was eventually got so loose that I could feel it by just touching it. Finally, I ended up stripping open the notebook and soldering it to its place.

However, the power connector in my ZT3340US doesn't feel loose, at least not as yet... but who knows. However, there's one thing that I can't piece together - if the connector was loose, why wouldn't the pc power up just on the battery? I mean the battery is 100% charged, yet, it doesn't power up.

Each of the two times that I managed to power up the pc, I had the power plugged in and battery too. With either of these out... it wouldn't even try to start.