My powerbook g4 (fw800 1.25Ghz 15") won't boot any more. Symptoms: after hitting the power button, it takes a while before it emits a long beep and flashes the sleep led a large number of times (I cannot count exactly how many times). This is different from the POST beeps mentioned on apple's web site: these beeps are shorter. This long beep also has nothing to do with the firmware upgrade procedures on other powerbook models.
When I remove RAM memory, it first beeps and flashes as already mentioned, and then, after a while, gives one short beep and two flashes (this indeed corresponds to the POST messages published by apple). Reseating RAM or other, good known RAM does not solve the long beep/boot problem.
I also tried the following: resetting pmu, resetting pram, without luck.
Then I opened it, and verified that all cables were seated correctly, unplugged the backup battery (which still has the correct voltage), reassembled everything, also without luck. With/without hard disk or optical drive: makes no difference. Also using it with either or both battery or AC power makes no difference.
Does anyone know what the long beep means? Is the logic board fried? Is there anything that I can try myself (I am somewhat experienced in fixing defective hardware in desktops and laptops). I probably have nothing to loose. I don't want to send it in for repair or spend money on a replacement board.
Thanks in advance