Classic Mac Hardware (Troubleshooting, Upgrading, & Modifying) > Mac CPU Upgrades

problems with G4 DA and Newer Tech CPU upgrade

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Hello everyone, I'm new to the board. 

I recently bought a PowerMac G4 Digital Audio with a Newer Tech Dual 1.6 GHz CPU upgrade module.  It had sat in a basement for years and came with a dead PRAM battery.  The computer would boot (strangely) to OS X before the battery replacement but not to OS9.  After the battery replacement I can't get any OS or install disc to boot.  I found a copy of Newer Tech's firmware CD and followed the instructions but it never got to the firmware upgrade screen.

Do I need the original CPU to do the firmware upgrade, or is there a way to upgrade the firmware with the new CPU module?

Before ever even attempting to upgrade the firmware OR anything else… try zapping the PRAM.

From a cold start… hit the power button (boot) and hold down the [command + option and p and r] keys. Hopefully you’ll get the boot chime and if so, wait for two more chimes before then releasing those four keys. If it then does not chime (or eventually boot completely after that release) you may have to reset the PMU on the motherboard. (Cover that possibility only AFTER the PRAM zap.)

AND even before the PMU reset, but after the attempted PRAM zap… simply unplug the machine and hit the power button… that should light up momentarily, then after a minute or two, plug in the power cord and attempt to boot again. If no change, then PMU ritual.

If it does boot after the zap… reboot holding down the option key until you might get a choice of boot sources to choose from. Choose OS 9. Again however, if it doesn’t boot after the ZAP, this option key boot attempt is moot.

I’m assuming that all was well with this machine previously and the firmware had already been upgraded (before storage) and that OS 9 was already resident on the HD with OS X?

Report back with your results BEFORE you attempt any possibly unnecessary firmware upgrade.

I was unable to zap the PRAM.  I hear the startup sound and then get dropped into Open Firmware.  At the top of the screen it says "WARNING!  MSSCR values mis-match".  I get a prompt where I can boot the mac or shut it down.  If I type mac-boot, I get the blinking smiling folder and question mark icons. Nothing happens, it just keeps blinking.

Welcome mopar300m

I see FBz is already tackling your issue. You have come to the right place.

Please have a seat until a technician replies. If you would like something to read while waiting then,
here are some "WARNING!  MSSCR values mis-match" readings.

That perpetual blinking signifies that it cannot find a bootable drive / device.
(I know… elementary.) ::)

Have you tried booting from an OS install disc (OS 9 or OS X)? Or any external drive or device?

If you can’t get the CD tray open to insert such a disc, open it through the front pinhole with a paper clip to then place the disc. THEN boot while holding down the “c” key AND if that doesn’t work try again while holding down the Option key with CD still in. This is all due to the possibility that your HD has problems that need be diagnosed (and possibly repaired) with Disk Utility on an OS installer disc. This would tell you if your HD is beyond repair OR even if it is the problem.

IF you can get it to boot from some other source (CD or external drive) then you may be able to recover or repair your existing HD.

If none of the above is possible, then you may have to install a new (or different) bootable drive.

I know it seems weird, but HD failures and corruptions usually happen at the most horrible times. In this case, very possible in a machine that’s been dormant for some time?

NOW, with all that said… I’d blow out (dust) the machine and check all of the internal plug-in connectors for the HD, mobo, and video card, etc. and maybe give it one more try. (The dead battery had not leaked at all?) Closely check visually for any leakage. But it does present like a failed HD. Hell, I’d even re-seat all of the RAM and pull all but basic necessary PCI cards. (Leaving the video card only.)

AND if you do have to install another HD - you may need to find a suitable original-type CPU in order to once again update the firmware (maybe) for the NewerTech CPU.

A bootable firewire drive with OS would be very nice right now for you if you can’t get it to boot from an installer disc… to run Disk Utility on your internal HD.

Can you send a pic of your internals? One HD or two / more inside? SCSI card or other added enhancements present?


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