PowerBook 5.9 won't power up

[Bug-Creator]

In the past week my PB got a bit erratic when I try to power it up:

The small "sleep" lamp in the front goes one but it won't go as far as accessing the DVD-drive (checking wether there is a disc). This still before one could access the OF or bootmenu.

Sometimes it did boot and it seemed it was somehow depending on how I was holding it. So I opened it and noticed that the mSata-module in the 2.5" bay had allmost slipped of the IDE-cable, reseated it and for a week or so it all seemed fine before the trouble started again.

My next assumption is that the PB allways thinks it's lid is closed and made a small test with my iBook. Hit powerbutton, close lid -> iBook switched off and stayed of when lid was reopened.
This result is somewhat differnent to the issue with the PB which seems to be stuck in sleep-mode.

Next step would be replacing the latch, assuming the lid-sensor is part of it.

 

[Mr Rabbit]

My next assumption is that the PB allways thinks it's lid is closed and made a small test with my iBook. Hit powerbutton, close lid -> iBook switched off and stayed of when lid was reopened.
This result is somewhat differnent to the issue with the PB which seems to be stuck in sleep-mode.

Next step would be replacing the latch, assuming the lid-sensor is part of it.

It seems like you'd see a flash of video/backlight before the screen goes dark if this was the case. Either way I believe the sleep sensor is built into the top case (around the trackpad) in this model.

From the manual:

Top Case
– As the sleep magnet has been relocated to the display bezel, the sleep sensor has
moved from the trackpad flex to the edge of the top case. Previous top cases will not
work with this system.

So the sleep LED on the front stays on? It sounds like it's not making it past POST. You can verify this by removing both RAM DIMMs and attempting to power on again. If it doesn't beep then it's definitely not making it through something in POST. If it DOES beep (three times) then it's at least healthy enough to see that the RAM is missing. At that point I would disconnect the hard drive, superdrive and other non-essential components and reconnect them one at a time, seeing if it POSTS (chimes) properly each time. When you reconnect something and it stops making it through POST then you've likely found a culprit.

Hope that helps!

 

[Bug-Creator]

O.k. back home and did some testing...

- removed the 2GB stick from the "back" RAM slot
- pressed PWR with no battery or charger (PMU-Reset ?)
- installed battery
- PWR on
-> does beep, sleep-light starts flashing
- put the 2GB stick in the "front" RAM slot
-> booted a few times without problem
- moved the stick back to the "back" slot
-> booted a few times without problem
- removed the 2GB stick
- placed a 512MB in the "front" RAM slot
-> booted a few times without problem

Problem is that the issue was hit&miss before as the PB would sometime work o.k. for a while and fail 100% on several attempts the next days, so I decided to keep it that way for atleast a week before trying again with that 2GB stick.

Wild speculation:
Does the PB/OF somehow store RAM-setting (size, timings, whatsnot) in NVRAM that could get corrupted by a failing coin-battery ?

 

[AmestrisXServe]

RAM size should be read by OF, but isn;t stored as a perpetual value. That does not rule out a possible corruption of PRAM/NVRAM. Perform a PRAM zap, and see if it improves.

You may have faulty RAM, but these symptoms seem a bit off, to be related to that.

The sleep settings may be stored in NVRAM. I posted a list of what is somewhere on this board, but it may be incomplete.

With any Mac problem, I can't reiterate enough: Zap the PRAM before doing anything else.

 

[Bug-Creator]

After dismantling the PB I found that the cable leading from the mobo to the WLAN/BT module wasn't firmly conected to the mobo (something I could have fixed after just removing the RAM cover ) seems that was the cause of the erratic behaviour.