what up lewis. . .has this 638 ever booted up normally?
which os are you running?
do you have other macs?
do you have any external scsi drives?
do you have any OSs on CD?
I can't say much, but usually, if I get this (has happened once on an overclocked Q610), I use an external disk as the boot device. If this boots, then you can rule out a few things. If you answer the above questions, we might be abe to help you further.
good luck!
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I have a problem with vintage electronics. . .I am working on it.
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