pwrbook G4 1.67 boots, screen goes black, wiggle mouse, screen lights (10 sec) , repeat, repeat

gil

Greetings!
15" silver, SN ends: V4RG4 Dual boots to 9.2.2 and 10.4.11

This is a sudden onset situation. Ran fine for about 1.5 yrs. Battery will not charge or hold a charge but OK on AC adapter.

Press start...boots OK - launch screen is "normal", i.e., initial gray screen is solid color rendition, illumination, etc. Gets to blue OS start screen - screen brightness sometimes flutters.

boot finishes, finder (desktop) appears.

desktop for about 10 seconds then display goes to BLACK (yes, I shouted that!) move mouse (no problem here), depress space bar, display relights - screen displays same info as when it went black - illumination is sometimes strong, sometimes w/ bit of flicker.

wait 10 seconds REPEAT, wait 10 seconds REPEAT...and REPEAT... and REPEAT,,,,

during those precious 10 seconds, system accepts mouse and mouse click commands OK

When screen relights, CD drive spins up and immediately shuts down

SAFE start-up works fine - but display & drive have same behaviors


No clue what to attempt next. Not smart enuf to know what to eliminate in a diagnostic effort.

All assistance welcome.

THANK YOU!

John

Hi! Thanks for the post. In many laptops (the iBook G4 1.33GHZ model comes to mind), that happens when you have a defective reed switch, which is a small sensor that determines when it is appropriate for the laptop to go to sleep. You can replace or remove the reed switch, and the problem goes away.

I had to do some digging, because it's been a while since I looked at at 15" PowerBook, but I believe the problem is a defective ambient light sensor. Please check out the link below for more details on where it is and how to get to it. But like a reed switch, I think you can just disconnect it, and if it is in fact the problem, it will stop falling asleep. It will also then not sleep when it should sleep, so if you want you can replace the sensor to restore normal behavior.

http://www.ifixit.com/Guide/PowerBook+G4+Aluminum+15-Inch+1.67+GHz+Left+Ambient+Light+Sensor+Replacement/643

Also, here's an iFixit article discussing a similar issue with a MacBook Pro:

http://www.ifixit.com/Answers/View/21756/How+do+I+diagnose+a+narcoleptic+Mac

Let me know if disconnecting it helps. If not, we can go from there. The next step would be to remove the topcase (which you'll already have to do to get the sensor) and try jumping the board by bridging the power-on pads with a screwdriver. The value of this is that if it doesn't fall asleep with the topcase off, you know the problem is something in the topcase, and if it still falls asleep, the problem is not the topcase.

But that's getting ahead of things, and hopefully you'll find disconnecting the ambient light sensor will reveal the issue.

Thanks!

John

gil

First, THANK YOU!

Here's more saga...

last evening ...
booted in safe mode - same issue
booted w/ battery removed from OX 10.4 DVD Behavior was w/o issue - go figure.
I purposefully shut down, reinserted battery

this morning -
tried (this is a key verb) to boot from same DVD. It spun up, and almost immediately shut down.

apparently no battery recharge at all.

AC adapter - w or w/o battery present NOTHING. Will not initiate start-up.

Will explore your suggestions - the ambient light sensor makes a lot of sense in regard to yesterday's (key possessive noun) behavior; not so much so today.

HMMMMMMMM

John

Wow, sorry to hear about the bad luck! So basically the laptop is completely dead and will not power up under any circumstance? Do you still get a green light on the AC adapter? Do you have another AC adapter to test with? Is your AC 65W? I ask because
45W AC adapters are not strong enough to power on 17" and some 15" PowerBooks that do not have a charged battery attached to supplement the power. But of course if your AC has worked with this machine for a long period of time you can disregard this idea.

When things get really weird like that, it makes sense to disconnect battery and AC, and also disconnect the AC from the wall, and just let everything sit overnight. There are a lot of cases in which a laptop will get a "bad charge", and letting the charge dissipate can restore at least some kind of functionality (maybe to how it was yesterday?)

Something else to try before you do that though -- the PowerBooks have a pretty strong PRAM battery which can maintain a charge. It's the weird "blob" thing that in most models sits on top the optical drive. I'd disconnect this and see if it affects your ability to power on.

Lemme know how it goes!

John

gil

Greetings & continued appreciation

So basically the laptop is completely dead and will not power up under any circumstance?

Correct earlier today - now it tries, gets maybe 15 seconds into start up then BLACK (yes shouting).

Do you still get a green light on the AC adapter? Do you have another AC adapter to test with? Is your AC 65W? I ask because 45W AC adapters are not strong enough to power on 17" and some 15" PowerBooks that do not have a charged battery attached to supplement the power. But of course if your AC has worked ...

adapter is non-branded replacement sans lights (or bells/whistles) labeled output is 24v 2.65A center post is labeled "+" but as you noted...it has been working.

When things get really weird like that, it makes sense to disconnect battery and AC, and also disconnect the AC from the wall, and just let everything sit overnight.

I will *purposefully* do this - it has been done w/o purpose, but perhaps *intent* will change the outcome?

PRAM battery which can maintain a charge. It's the weird "blob" thing that in most models sits on top the optical drive.

I will try this too. Stand by...not much worktime between now and deer hunting in the AM.

THANK YOU

Gil