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6100 Boot Loop/Freezing

Posted by: daniel_chapstick on 2023-05-16 08:04:47

Hi all,

My 6100 has had two major issues recently:

1. When I try to start it up (still chimes and zuluscsi is installed with 7.5.5), the 6100 freezes at startup.

2. When I try to reset it, the 6100 enters a boot loop, where it will keep chiming and attempting to reboot but never goes past the start up screen.

I am gonna guess this is a sign of bad capacitors? I tried replacing the PSU with another PSU of a functional Centris, but it still encounters the same issues.

Posted by: Nixontheknight on 2023-05-16 08:54:22

Hi all,

My 6100 has had two major issues recently:

1. When I try to start it up (still chimes and zuluscsi is installed with 7.5.5), the 6100 freezes at startup.

2. When I try to reset it, the 6100 enters a boot loop, where it will keep chiming and attempting to reboot but never goes past the start up screen.

I am gonna guess this is a sign of bad capacitors? I tried replacing the PSU with another PSU of a functional Centris, but it still encounters the same issues.

recap the logic board and PSU, but it might also be a sign of a bad ROM, but I'm not sure

Posted by: Phipli on 2023-05-16 09:05:13

Hum, not sure that really sounds like caps. Might be just a bad boot disk SCSI ID or termination issue.

How is your SCSI set up?

Posted by: macuserman on 2023-05-16 09:48:21

Also pull your memory sticks if you have any and try it with only the logicboard memory.

Posted by: 3lectr1cPPC on 2023-05-16 10:11:34

No matter what the problem is at this point 6100s are on the "need to recap" list. They're leaking and failing frequently. This is a system from 1994 we're talking about after all.

Posted by: joshc on 2023-05-17 13:28:11

Check the 601 is not overheating as well - can cause all sorts of issues. There is no thermal shutdown protection on these machines. They will just crash/freeze up if the CPU overheats. It will run very hot but if not repasted it should be by now.

Posted by: Nixontheknight on 2023-05-17 16:24:40

Check the 601 is not overheating as well - can cause all sorts of issues. There is no thermal shutdown protection on these machines. They will just crash/freeze up if the CPU overheats. It will run very hot but if not repasted it should be by now.

Another thing you can try is installing a CPU fan that can be powered by Molex

Posted by: mdeverhart on 2023-05-21 19:36:58

It will run very hot but if not repasted it should be by now.

While I agree that the thermal paste is certainly shot by now, be aware that the 601 CPU is exceedingly fragile, and that tremendous care must be taken if you attempt it. See the thread here:

Power Mac 7100 PPC 601 CPU package damaged

Someone recapped my Power Mac 7100 with a beautiful set of 20+ tantalum caps. I received the board and assembled my Quadra / 7100 FrankenMac, only to discover a no chime / no boot condition. Re-seated ROM, cache, RAM, etc. and no change, so I pulled the heatsink off of the 601 CPU and found what...

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