Power Mac G4 - please help

If not used for a couple of years it is quite possible the PRAM battery is dead. PRAM stores basic startup information (including monitor information) and a bad battery can actually prevent a computer from starting.

Decide what you want to do. If you just want to recover data there are options for that. If you want to get it up and running again you can start with replacing the PRAM battery.

Texas Mac Man's PRAM, battery, PMU tutorial - https://sites.google.com/site/macpram/mac-pram-nvram-cuda-pmu-battery-tutorial

Apple's PRAM reset directions - http://docs.info.apple.com/article.html?artnum=2238

If you have a digital multimeter you can check the condition of your present battery. It should read at least 3.2V if it is the 3.6V half-AA battery type. A new battery provides 3.67 Volts DC. A bad battery provides under 3.2 Volts DC. Ideally this should be measured while the battery is under load; added recommendation from Hans777:

>I have recently found out that an exhausted battery will still indicate >3.6 V with a high internal resistance VM.

>

>Checking incircuit: powercord disconnected press PMU reset button for >about 5 sec before measuring.

>

>Checking outside: load the battery with a 1500 Ohm resistor when measuring.

Alternatively, test the battery while it is still in the computer.

If the battery is more than 5 years old, especially if you totally disconnect the computer from the power regularly, or have left it unplugged for several months at one time, it is likely the battery is dead.

If you just want to recover data you can try using the G4 in target disk mode:

How to use FireWire target disk mode - http://support.apple.com/kb/HT1661 - includes description of hardware and software requirements.

Target Disk Mode - Mac OS X 10.6 Help: Transferring files between two computers using FireWire - http://docs.info.apple.com/article.html?path=Mac/10.6/en/8443.html

[What to do if your Mac doesn't enter FireWire Target Disk Mode|http://docs.info.apple.com/article.html?artnum=75414], also read about [Open Firmware Password Protection|http://www.apple.com/support/downloads/openfirmwarepassword.html] which can disable Target Disk Mode.

If that doesn't work and you really don't care about the computer you can take out the drive and put it in an enclosure and use it as an external drive, or get something like this which lets you temporarily connect a drive:

"Newer Technology Universal 5.25/3.5/2.5" Hard Drive & Optical Drive to USB2 Adapter w/Power. Everything you need to Plug and Play any SATA/ATA/IDE/ATAPI Drive via USB 2.0/1.1 port. Fast, Simple, Plug & Play. GREAT for transferring data, etc. (NWTU2NV2SPATA)" - http://eshop.macsales.com/item/Newer%20Technology/U2NV2SPATA/

Did you try a PRAM reset?

Will it start in Safe Mode (hold down shift key while starting, be patient)?

Mac OS X: Starting up in Safe Mode - http://support.apple.com/kb/HT1455

What is Safe Boot, Safe Mode? (Mac OS X) - http://support.apple.com/kb/HT1564

Safe Boot takes longer than normal startup - http://support.apple.com/kb/TS1884

Mac OS X 10.4, 10.5 - Computer shuts down during Safe Boot - http://support.apple.com/kb/TA24054

Safe boot mode runs a directory check command similar to that used by Disk Utility's repair. In OSX 10.4 and later it ignores some stored information (cache) that is normally read that speeds up the boot process, and it moves some caches to the trash. It also uses only System fonts and disables all Startup Items, third party items, and any Login Items. Networking and some video components may also be disabled.

Do you have a second Mac handy and is it running something other than Lion which might allow you to run the application from the G4 on the other computer?

Note that not all applications display registration codes. Sometimes it is only on the installer disc.

Apple Store still sells the batteries??😮 It must be the only thing they carry for computers that age.

$25?! you can get one for $15 from Radio Shack I believe, or even cheaper from www.mac-sales.com

You didn't say anything about another Mac (though I suppose there is one somewhere because otherwise what's the point in updating software), so I guess you didn't try the Target Disk Mode.

If we knew what software this was one of us might have it and could tell you if it's even worth the bother. As I said, in some cases you really, really need the number off hte disc.

Lion likely will not run a truly old application from a G4. It depends upon whether or not the software included code for Intel and not just PPC. For that you'd have to check the application itself in Finder or check the specifications for that version. Anything older than 2006 will likely not have Intel coding (called Universal if it is for both PPC & Intel).

Depending upon the application it may also not run it unless it has components installed in the system folders. Can't tell without knowing which application

It may be the battery. Leaving the computer plugged in will extend the life of a PRAM battery but all eventually die. My non-starting issues have all been cured by new batteries, but I can't say for certain in your case. It's the first place to look in your scenario.

Batteries Plus may also stock the battery, or similar vendor. It's probably the half AA size so it is not common.

Try starting in Safe Mode.

Mac OS X: Starting up in Safe Mode - http://support.apple.com/kb/HT1455

What is Safe Boot, Safe Mode? (Mac OS X) - http://support.apple.com/kb/HT1564

Safe Boot takes longer than normal startup - http://support.apple.com/kb/TS1884

Mac OS X 10.4, 10.5 - Computer shuts down during Safe Boot - http://support.apple.com/kb/TA24054

Safe boot mode runs a directory check command similar to that used by Disk Utility's repair. In OSX 10.4 and later it ignores some stored information (cache) that is normally read that speeds up the boot process, and it moves some caches to the trash. It also uses only System fonts and disables all Startup Items, third party items, and any Login Items. Networking and some video components may also be disabled.

If it won't start in Safe Mode do you have the installer disc for the OS version on the computer? Will it boot to that (hold down C key while starting)? If it will, try running Disk Utility to repair the drive.

The screen is still going black? I wonder if there is something being displayed that you can't see and pressing enter confirmed something that invoved shutting down the computer. I don't know why the screen would blank like that after working though.

Video card, or monitor, or... This is the kind of situation where you have to have pretty much two of everything to swap out items to test.

Alternatively pursue the line I had suggested earlier which is to find out if this is all worth it and if the application you want even displays a registration number. Many of them do not so people can't just copy somebody else's number (say in a library or computer lab) and enter it. If we knew which application this was, maybe one of us has it and could tell you if we see it.