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I have a Power MAC G-4 with a Apple display 21" ? About 6 years old in great condition well, I use to use this daily untill about a year ago I got a Gateway Notebook, and that took over so my MAC only got used a few times a month,I got rusty. So yesterday I got a new Nano and wanted to use it with my MAC I started it up ran Disk Utility all OK. when my Software Update poped up I started it and it installed the new Itunes then when it started the JAVA app. my screen went blank and the thing shut down. I re-started and my Monitor is blank I only get the 3 light flashes on the monitor. So checkin my manual is says my display is detecting input in the wrong video format. Check compatible with graphics card and check software installed correct.?? That is foriegn to me I know where my g-card is but why that? So I tried to reset my PRAM by the Command option P and R keys and I get nothing after the two chimes. Can anyone help??? The old MAC FixIt site use to have an answer years ago, I believe I heard about the 3 light flash before but to long ago.. Thanks....
Just a thought: Has the Mac ever had its internal backup battery replaced? They last 3-5 years but will weaken sooner if the computer is left unplugged for periods of time. A weak battery can cause strange symptoms, which is why I ask.

For the record, I replaced the battery in my G4 DP 450 after 4 years. It would partially start up and then spontaneously shut down. The new battery cured it.

The battery may be in stock at Radio Shack, or you can get it from OWC. If you need instructions, you can download a video here.
Originally Posted By: ynotmit
...I only get the 3 light flashes on the monitor. ...The old MAC FixIt site use to have an answer years ago, I believe I heard about the 3 light flash before but to long ago.. Thanks....

Depending on the specific model G4 you have the three light flashes are described in this Apple Knowledge Base article or this one but in either case three flashes means no good RAM banks are found. shocked

I would start by opening up your G4 and removing and reinserting the DIMMs. You may simply be the victim of corrosion and removing and reinserting will often clear that up.
Are you and ynotmit talking about the same phenomenon?

> I re-started and my Monitor is blank I only get the 3 light flashes on the monitor. (Emphasis added)

Your linked doc, on the other hand, says
Quote:
In addition to the beeps, on some computers the power LED will flash a corresponding number of times plus one.
(Emphasis added)
Perhaps this can be of help, together with the duration (short, long) of those 3 flashes: Apple LCD displays: Power light flashes.
Originally Posted By: alternaut
Perhaps this can be of help, together with the duration (short, long) of those 3 flashes: Apple LCD displays: Power light flashes.


But your linked doc includes the same anomalous language...

Quote:
If one of the Apple LCD displays detects an error condition, the power LED will flash in a certain pattern to indicate the issue.
(Emphasis added)

as does joemike's linked doc.

I wonder whether ynotmit's original statement, "I only get the 3 light flashes on the monitor." (Emphasis added) was accurate?
Originally Posted By: artie505
But your linked doc includes the same anomalous language...

The language you quote isn't so much anomalous as as generic: there is a problem, specified by the pattern of the flashes as outlined by the KB article. Apparently ynotmit noted three short flashes of the display's power light, because when he checked that phenomenon in his display's manual he came up with exactly the same diagnosis as the KB article I quoted.

That said, the problem is now why the PRAM reset won't seem to work. There's also the possibility that the G4's display hookup isn't OK; perhaps it was incorrectly reconnected for this particular use after sitting idle for a year, the video card got bumped loose while setting up, or a relevant file in the OS got florfed somehow. I'd start with reseating the videocard and checking any associated cable hookups.
I've seen them flash but the only useful flash would be the one to indicate a bad power supply. (usually means it's supplying some, but not ALL, of the powers required)

It's been my experience that a partial pack failure is a very rare event. Most times when the pack goes, it dies completely, since it's a switching supply. Other than the pack, any other flashes indicate a fatally wounded display. (not easily repairable despite whatever is wrong) So ya, the lights aren't very useful. 98% of the time you see a flashing monitor light, the display is shot.
> Apparently ynotmit noted three short flashes of the display's power light, because when he checked that phenomenon in his display's manual he came up with exactly the same diagnosis as the KB article I quoted.

Sounds good... Either that or (less likely, I guess, but still a possibility) ynotmit really has got a flashing monitor and misread/glossed over the power light part.

It would be nice if se'd post back, acknowledge our efforts on hir behalf, and give us an update. frown
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