G4 cube dead

Scorpio_ny · 2026-02-16T02:36:09+0000

I was looking what you tried...any chance the video card developed an issue?

Fred1212 · 2026-02-16T03:08:42+0000

Thanks done all the cleaning, checks etc thinking logic. I've replied to your DM cheers

Fred1212 · 2026-02-16T03:37:55+0000

@Scorpio tested video card in G4 tower works.

Fred1212 · 2026-02-16T04:00:56+0000

Just hunting through the junk box. I've a XPC7400 RX486PK, the cube has a XPC7400 RX450SK. Can I try this to see if its the CPU?
Also found a XPC7400 RX450PU

Fred1212 · 2026-02-16T05:14:21+0000

OK bit the bullet and put the XPC7400 RX486PK in and miraculously it works. Looks like its only a 350mhz chip? but it is at least working. We'll see if it lasts

Fred1212 · 2026-02-16T06:13:50+0000

And its dead again!! tried to install MacOS 9.2 started OK then froze and won't go again. I think its the logic board unfortunately

herd · 2026-02-17T15:55:13+0000

The 466MHz CPU board probably came out of a DA, so the speed in a Cube makes sense: 466 in a DA is 133 x 3.5, so the Cube with a 100MHz bus runs it at 350MHz.

Is temperature a factor? Is it more stable when cold? If you run it out of the case with the boards exposed, can you press on chips, flex the boards, slightly bend wires/connectors, etc. to locate the problem? Are the boards dirty/corroded? Contact cleaner on the various connectors may help. The 300-pin connector for the CPU is a bit fragile and its pins are easily bent or contaminated.

Also, I've worked on a few Cubes that had a factory bodge applied to a regulator, which runs very hot. Does your board have this bodge, and do the components look intact?

Scorpio_ny · 2026-02-17T16:09:51+0000

Here is a Hail Mary: in the past, many people reported the similar issues your are seeing and it was caused by a faulty power button. I believe there is a way to power it on with the power button disconnected. Have you tried that?

G4 cube dead

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