iBook won't power on after attempted PMU reset
Hi there. I recently purchased a used iBook G3 (700mhz/20gb HD). It was working fine for a week, and then all of a sudden, it died and no longer wants to power on.
This is the sequence of events.
It was having some battery issues -- the battery would show 30% or better charge, but it would go to sleep, as though it had no charge. Upon plugging it into the AC cord, it would then show 0% charge (until it fully charged, of course)
I attempted to reset the PMU by powering off, disconnecting AC, and pressing the CTRL-OPTION-SHIFT-PWR combination. Nothing happened, that is, no tone, or change in light on the power cord.
From that point, the iBook would no longer power on at all. I tried with both the battery in, the AC cord connected with the battery, and the AC cord alone with no battery, and still no luck.
I tried attempting to reset the PMU again, with the aforementioned multiple formations.
I don't think it's the DC board, as the power cord continues to shine green whenever it's plugged in.
I don't think it's the battery, in spite of the battery charge level issues, it still shows a full charge when pressing the level button. Also, it still won't power up even with the battery removed and only the AC cord connected.
I'm not sure, but I don't think it's the logic board, as it didn't exhibit the flickering screen issue associated with the logic board.
The RAM and Airport card are seated properly, and I tried powering on with them both removed, and still no luck.
It was running Tiger 10.4.11
Any idea what happened here?
What I found when dissassembling my G3 iBook was a faulty capacitor at the spot marked C91 on the motherboard. This is the thing that looks like a battery (and actually does the same purpose in this case). It was already leaking but nothing serious. Back in the days Apple would just swap the entire board, but you won't get a new board, at least not from Apple.
This capacitor is actually responsible for keeping the settings of the PMU alive for a while even with all power disconnected from the machine. So, when it finally drains (after some days) a "dead" iBook may come alive for no apparent reason, because the "stuck" PMU has finally reset.
The solution to this is to swap the capacitor for a new one, which is quite easy for those who are able to solder. Find a friend who can. The capacitor is rated at 0.33 F, 5.5 Volts and you'll be able to buy one online if you do a search for EEC-S0HD334H which is the part number for a Panasonic model. Any model with the same rating and mounting will obviously work.
由 Thorstein 完成的