G4 light flashes but won't start

Hi,

Ouch! 863.56?? I could get a new logic board, possibly used or refurbished on ebay for 90 percent less! Anyway, problem could also be the front panel board. I had this same problem several months back. The computer wouldn't turn on, after a few times of seeing the light blink fast. Try seeing if you can get a replacement front panel assembly. They are only 40 bucks and not too much problems in replacing it. It took me all but 20 minutes.

Your processor is probably fine, as these MDD machines are built tough.

Hi-

Welcome to Discussions!

How many times does the power light flash? This could be related to the Power On Self Test, and the reporting of a problem (usually accompanied by beeps, though not always).
Power On Self-Test Beep Definition

Hello,
I haven't got the faulty G4 in my premises since I hadn't enough time to spend on it, but I also found an interesting page on Apple Support that could help determine if the front panel is faulty :
http://docs.info.apple.com/article.html?artnum=95064

Hope this could help you.

Michel

I'm having the same problem. I shut the machine down when I went on vacation and now it won't start up. The light doesn't really flash, though. It just lights up when I push it - and then nada. I'm at a loss, too.

I have the same computer and I have the same problems. I push the power button and nothing happens. So I took my G4 to the nearest apple store 4months prior and they replaced the internal power supply and it worked fine up until a few weeks ago. After the same problem occurred again I took it back and now apple is telling me that I need to replace the 1.25 GHz Dual multiprocessor and logic board which costs $863.56. The apple tech guys are telling me to just upgrade to a new computer and forget about the G4 but I'm not really in a position to spend much $$ and I still really like my G4 better than any new computer. Anyone know what causes these types of problems? Also, does anyone have any suggestions on which path to take? Mac Mini?

I'm having the same symptoms. We had a power outage recently, and afterwards my PM MDD G4 won't turn on.

The symptoms are that if I plug it into the wall, then press the power button, I will see the light on the power button as well as see the fans spin for a moment as well as a red light flash on the logic board itself but that is it.

Subsequent presses of the power button the button light will not light, but the fans will move briefly and the light on the logic board will flash.

I've tried removing the battery, resetting the PMU and leaving it for 30 minutes, but still no luck.

I've previously had to replace the circuit board behind the power button on a older blue and white G3 machine, but I don't remember the symptoms.

I'd be willing to take the gamble that it is the power switch board and pay $40 to replace it if it sounds like this might be it. Anyone have any ideas?

Also, where can i get that part for $40?


Thanks!!!

R.R. Hornback
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Seems like the symptoms of this problem can be do to one of three things:

1. Power Supply
2. Logic Board
3. Front Panel button

Anyone have any idea how to determine which is the culprit without having to replace them one by one?

I can buy a used Front Panel for $25, so that might be where I start.

Funny how we're finding ourselves several in the same case !
I've juste got my neighboor's MDD G4 this afternoon with the exact same symptoms.

As I had already seen this with a Dual G5, even if it's not the same box, I really think it's a PMU related problem (or maybe SMU if it already has one ?).

Unfortunaltely, the docs available are never about this peculiar type of G4, always for former ones, so I cannot really be sure of the right way to reset it's PMU. As it has a PMU reset button, the procedure should be : pull the power cord off, evenutally take back the battery, replace it, push the reset button, and wait at least 10" before pluggin the power back.
I also tried the method for those boards without reset button : 10 minutes without power nor battery, replace battery, et voilà. This lead me to a totally non fonctional computer : no light no fan nothing. Then reset PMU the first (and normal) way. And only got back to : fans up, light when button pressed, drives are checked by BIOS, but nothing boot. The computer can be stopped by pressing long time on the power button.

Anyone would have an idea around here ?

Michel

I think all these problems are leading to a faulty front panel board. I had this problem awhile back. The replacement part is around 40 dollars, and is very easy to install. Took me only 20 minutes to do the whole procedure.

After about 20 years away from Apple, I'm getting associated again. I've been a professional PC tech (other variations apply) for over 10 years now. I recently acquired a G4, 933, but the person did not have the software, or supervisor password. So last night I upgraded to Leopard. This morning we lost power for 45 minutes, now when I try and boot up the G4, the power light flashes, then goes off and that's it.
I came on here looking for answers. some of you are talking about the front panel, I'm not an expert in Apple, but I don't think that is it. I am, however an expert on PC's and when I've seen similar symptoms in the PC world and it typically is the motherboard, what apple apparently refers to as the logic board. I don't think it's the power supply, or you probably wouldn't get anything.

I will keep researching, and bring back any further ideas

Welcome to Apple Discussions.

See if you can boot from the Leopard CD by holding the "C" key at startup. If it starts, then the logic board is probably OK. I suspect the LB will turn out to be OK.

When I get an older Mac that's likely been off wall power for several months, I start to suspect the PRAM battery which has been mentioned earlier in the thread. Depending on model, a dead PRAM battery can mimic a total logic board meltdown, demonic possession, or only create a minor glitch.

The G4 uses a 3.6V 1/2AA lithium battery. Radio Shack has it as part number 23-026 but it's overpriced IMHO. I buy them online for about US$5 and stash the supply in the veggie drawer of the frig to keep them fresh a little longer.

I order batteries from this vendor and pay shipping, or from this vendor who pays the shipping even on small orders.

Bt all means, if you need the battery right away, there is no denying that Radio Shack is the best option if you can deal with the $15 price tag.

Has anyone found any solutions that fixed the issue?

I see different issues in the thread so far.
1. Flashing light and some fan action but no boot
2. Power light illuminates when pressed but machine doesn't start/do anything
3. Flashing light/logic board flashing red light.

#2 which is what I'm trying to solve for my father, seems to be either power supply related or something to do with the system not properly shutting down. (all guesses here BTW)... I've tried cleaning the machine (G4 Quicksilver Dual), Taking RAM out and re-seating it. New Battery. etc.
Still, the machine will only startup if the power cord (or UPS) is unplugged (all power disconnected) after sleeping or shutdown. I've even tried removing all peripherals. So my question to the community and anyone from Apple watching this thread. What is the real solution, minus getting a new machine. Since this has been an issue since the machine was only 1yr old I find it unacceptable to say "sorry folks you just got lemons".

The machine runs like a true champ (tiger) and is a shame this power ting seems to be plaguing us all. I love Apple, their quality hardware/software and especially Customer Service (hint hint 🙂.

Thanks All!

wiliamsmith9 wrote:

I love Apple, their quality hardware/software and especially Customer Service (hint hint)

You're "hinting" in the wrong place. People here are owners and users, not Apple employees. That said, you stand a better chance of someone here finding the fix than anyplace else. My best advice is "stay tuned."

Good news (at least for my situation)...

I was able to remedy the issue by unplugging and opening the box>
removing pressing, holding PRU button for 15sec +->
Removing the battery (is a new one)> Repeating the PRU press>
Then (this was a shot in the dark) Took the two RAM chips out checked for any dust etc and replaced them BUT alternated the slots> Replaced battery>
Plugged back in power> Hit PRU button again (15 secs)>
Started up machine and now the issue is gone. Sleeps shuts down everything, just like new...

Mind you, any number of things I've done may have corrected the issue (going on for over 2 yrs). I'd tried everything but the RAM alternation prior to doing this, it was just what I'd call a napalm attack. I don't think this will work for everyone. But if it can help one person...

Good luck folks.