Mac Forum / General / Hardware / August 2004

I am having a problem not being able to get power to my iMac (G3-slot
loading), and am wondering what I need to replace (logic board, power
supply, etc.).

M5521 - SN RN0018N2HTH
350MHz/512 L2/64MB (upgraded to 128MB)
6GB/CD/56K/BB

The symptoms are that when I depress the power button, either on the
keyboard or on the cpu, the power light on the Mac and the lights on the
keyboard come on for only a fraction of a second and then go off.  If I
hold down the power button continuously, once and awhile the lights will
flash on and off several times, and then I might hear the screen crackle
momentarily or the hard drive start to spin up.  However, the system does
not start to boot (and no 'dong'), even if I release the power button as
soon as I hear either the screen or the drive start.

This happened a couple times before about a month ago.  Repeated attempts
over a one hour period have succeeded to boot the system in the past, but
not this time.

This afternoon I replaced the lithium battery on the logic board, but
this did not help.

This appears to be OS-independent, since it has occurred with both Mac OS
10.2.1 and with Debian Linux (either installed as the sole OS).

This is a power issue and not a boot issue, as the system does not
even begin to power up.

Any suggestions would be appreciated.

Thanks,
Barry Skidmore