Q: Apple G5 not starting black screen. No chimes. After a few minutes the fan kicks in running very loud. Have to unplug to stop the fan. Help.

More detail:

Apple G5. 2.3 GHz Power PC

Model No: A1117 EMC No: 2030

Model Identifier PowerMac11,2

Processer Name PowerPC G5 (1.1)

Serial No: CK******R6V

PMGS Dual 2.3/512/250/6600

Mac OSX 10.5.8

1. 2.5GB DDR2 SDRAM

Apple G5 not starting black screen. No chimes. After a few minutes the fan kicks in running very loud. Have to unplug to stop the fan. Have tried apple/option/r then powering on and pressing p. Same result.

I then replaced the PRAM battery and bingo it worked. Now a few weeks later the same problem occurred. This time replacing the battery had no effect.

I reset the SMU, but pushing the SMU reset button, but no go.

I cannot reset the PRAM (from online instructions) because the screen is black and there are no chimes.

I removed the RAM and started the machine. No chimes and the fan kicks in running very loud as before. I put the ram back in and restarted. After a few secs there were two high pitch beeps and the fan kicked in running very loud.

I then realized that in fact I had forgotten to put the fan mechanism back in. So what was making the fast running fan sound?

I put the fan mechanism back in and restarted. The same result two loud beeps and the fan kicks in.

Power button flashing.

On board.

Red light top right.

Red light middle left (third led down),

Orange light middle left (fourth led down).

At the bottom of the board there is a green (SYS) led flashing in sync with the power light which flashes two times, repeating.

When I switch off two lights remain on

Red light top right.

Orange light middle left (fourth led down).

I suspected it might be a RAM problem, so I too ram from a sister G5 machine and put it in

Bingo it worked.

Memory now in place

265MB DDR SDRAM, Speed PC2-4200U-444

265MB DDR SDRAM, Speed PC2-4200U-444

1GB DDR SDRAM, Speed PC2-4200U-444

1GB DDR SDRAM, Speed PC2-4200U-444

HOWEVER     

A few weeks later bang! Same old problem again black screen fan kicks in.

H  E  L  P  !

<Edited by Host>