[rslifka]

This must not be a common problem because the word 'checkstop' isn't anywhere, certainly not with any frequency. I get hard locks when using my machine. An LED labelled CHECKSTOP lights up inside the case. Here's what I've done:

- Apple PM DC manual: If this light comes on, take to service provider.
- Local apple store: Can't do much w/out more information. He ran all of their diagnostic software overnight and didn't find any issues. Only thing remaining is possibly bad RAM, but it passes the RAM check so I didn't think that could still be an issue?

Any advice guys? These random crashes are killing me.

Rob

[Big Mac]

I really would love to know why those LEDs were put into the PCIe G5s. But I guess if I were trying to figure out the problem I would run the Mac with only the stock RAM to see if that solves the problem. If they were to continue, I would take it in for service.

[mountainash]

Bad RAM can pass tests.

Random crashes can also be caused by other factors, like heat or even a faulty hard drive cable.

A quick test to confirm RAM problems, is to start the computer up from cold, open up activity monitor, and then as many other programs and data as you can to fill RAM. If the RAM is bad it should crash once the bad RAM is accessed. If this test shows nothing, it could still be the RAM.

Removing RAM and not seeing the problem is a much more certain test.

Also, are you using any other things that the service tech didn't test? Like do you normally have it connected to a network, or printer, or firewire device or so forth. Often techs don't see the same problem because they aren't testing the same setup, just a part of it.