[mitchell_pgh]

I know, I know, it's my own damn fault for not taking my time and upgrading the system step by step, but here is my situation.

I picked up two 350 iMac slot loading Macs for $50 (both worked, but one was missing a keyboard/mouse).

I started updating the first mac. It had OS 9.0 and I started installing Jaguar (without the firmware upgrade: I didn't know about that situation at the time) on the system (everything was going fine). I got the whole thing updated to 10.2.6 with all of the various iApp upgrades. I rebooted the computer and got a red screen. Thinking that it was a hardware problem, I rebooted again... and then one more time... (it was coming up with a very dark red screen and I could hear the computer booting up) After the third restart, the monitor wouldn't even turn on and now the hard drive doesn't even spin up. I turn it on and it makes the chime and then makes a click noise and sits there making a tapping noise.

I know it's the firmware issue from late last year, but what do I do? There is a disk in the drive and I can't boot from a CD.

Could I swap out the updated HD with the other HD and then try to update the firmware (if the OS even boots up)

Help!?

[Azzgunther]

Yes, the swap idea is a very good idea.

Reset the PMU. Here's my pre-packaged "how to" reset the PMU :

RESET PRAM
Reset the PMU

Many system problems can be resolved by resetting the PMU chip. Whenever you have a computer that fails to turn on, follow this procedure before replacing any modules.

The PMU (Power Management Unit) is a microcontroller chip that controls all power functions for the computer. The PMU is a computer within a computer. It has memory, software, firmware, I/O, two crystals, and a CPU. Its functions is to:

# Tell the computer to turn on, turn off, sleep, wake, idle, etc.
# Manage system resets from various commands.
# Maintain parameter RAM (PRAM).
# Manage the real-time clock.

Resetting the PMU Chip Procedure

1. Disconnect the power cord and check the battery in the battery holder (BT1). The battery should read 3.3 V to 3.7 V. If the battery is bad, replace the battery, wait ten seconds, and then reset the PMU (refer to the next step). If the battery is good, go to the next step.

2. Press the PMU reset switch (S1) once on the logic board. Do not press the PMU reset switch a second time because it could stop the PMU chip from responding.

3. Wait ten seconds before connecting the power cord and turning the computer on. If the computer turns on, go to the next step. If the computer does not turn on, there is something else wrong with the computer.

Note: This entire procedure resets the computer's PRAM. Be sure to reset the computer's time, date, and other system parameter settings.

Important: Be very careful when handling the main logic board. Ground yourself to a metal object to draw any static electricity off of yourself. Remove the battery when handling the logic board so the PMU is not affected. The PMU is very sensitive and touching the circuitry on the logic board can cause the PMU to stop responding. If the PMU stops responding, the battery life goes from about five years to about two days if the PMU is not reset. The PMU chip is located near the battery; refer to article 95035: "Power Mac G4 (AGP Graphics/Gigabit Ethernet): Logic Board Diagram" for the location of the PMU button.