G4 MDD won't start after a power outage
My trusty G4 MDD Dual 1.25 GHz (M8570) has been a true workhorse for the past 6+ years and has performed almost flawlessly. However, I just experienced my first major problem with it, and am in search of some guidance. I’ve spent a few hours reading through the numerous topics here that I believe to be germane to my issue, and have collected lots of useful information and made copius notes, but unfortunately, I still haven’t yet found a solution. So please bear with me!
This past weekend, my neighborhood suffered an 11-hour power outage due to a windstorm. I normally keep my MDD plugged in when it’s not in use, but not turned on or in sleep mode. The power cord is connected to a decent, commercial-grade Isobar power strip with a surge-protection feature.
When I went to use the computer on Monday morning, it wouldn’t start. The MDD’s power button lights up when pressed, and goes out when I release pressure on it. My 20-inch Cinema Display’s (A1038) power button also lights up when touched, and goes out when I remove my finger.
I initially suspected that the PRAM battery might’ve gotten drained during the power outage, so I replaced it with a new one measuring 3.6 volts as part of a logic board reset. When that failed to achieve a normal start-up, I performed a PMU reset. Still nothing.
While I normally turn the computer on using the Cinema Display’s power button, I had read about problems with the MDD’s power button board, and per a suggestion found here, I attempted to start it with an almost-new Apple USB keyboard with a built-in power button (model M2452), but that didn’t work.
I’ve read a lot about power supply failures here on the G4 MDDs, and am hoping/praying that this isn’t the problem with my machine. But this raised two questions:
a) Since the Cinema Display gets its power from the MDD via a 28-volt ADC connection, can I presume that since the display’s power light illuminates when touched that the MDD’s power supply is functioning normally?
b) Does the red LED on the logic board illuminate whenever power is supplied to the computer, or only when the computer is on and running? The LED is not illuminated right now, presumably because I can’t get the machine started.
I don’t own a multi-tester, but I guess my next step would be to purchase one and start checking things, beginning with the +5V trickle charge from the power supply. I also own a G4 Sawtooth that could be cannibalized as part of a rescue operation, but I don’t believe that there are many (if any) interchangeable components between the two machines.
Any guidance would be very much appreciated.
This past weekend, my neighborhood suffered an 11-hour power outage due to a windstorm. I normally keep my MDD plugged in when it’s not in use, but not turned on or in sleep mode. The power cord is connected to a decent, commercial-grade Isobar power strip with a surge-protection feature.
When I went to use the computer on Monday morning, it wouldn’t start. The MDD’s power button lights up when pressed, and goes out when I release pressure on it. My 20-inch Cinema Display’s (A1038) power button also lights up when touched, and goes out when I remove my finger.
I initially suspected that the PRAM battery might’ve gotten drained during the power outage, so I replaced it with a new one measuring 3.6 volts as part of a logic board reset. When that failed to achieve a normal start-up, I performed a PMU reset. Still nothing.
While I normally turn the computer on using the Cinema Display’s power button, I had read about problems with the MDD’s power button board, and per a suggestion found here, I attempted to start it with an almost-new Apple USB keyboard with a built-in power button (model M2452), but that didn’t work.
I’ve read a lot about power supply failures here on the G4 MDDs, and am hoping/praying that this isn’t the problem with my machine. But this raised two questions:
a) Since the Cinema Display gets its power from the MDD via a 28-volt ADC connection, can I presume that since the display’s power light illuminates when touched that the MDD’s power supply is functioning normally?
b) Does the red LED on the logic board illuminate whenever power is supplied to the computer, or only when the computer is on and running? The LED is not illuminated right now, presumably because I can’t get the machine started.
I don’t own a multi-tester, but I guess my next step would be to purchase one and start checking things, beginning with the +5V trickle charge from the power supply. I also own a G4 Sawtooth that could be cannibalized as part of a rescue operation, but I don’t believe that there are many (if any) interchangeable components between the two machines.
Any guidance would be very much appreciated.
Power Mac G4 MDD Dual 1.25 GHz, Mac OS X (10.4.11)
