Cube problem

[galgot]

Good day gents,

Inherited a G4 Cube that refuses to boot. no chime (does Cube chime anyway ?). no video on any screen I try, either the cubes one or a VGA.
Only some quick flashes (4 ?) on the main power and screen buttons. With a DS2 red led lit on the main board, near the ram slots.
Think it's a ram problem...?
Tried resetting the ram, using only one slot and moving the ram to each slots for testing, using different ones... no joy.

Strange thing is when I try to boot it with the original HD , there is a click-clicking noise for a while, even tho that HD seems to be fine as I removed and tested it. I've plugged it to a usb adapter and could read and test it on another mac.

replacing the HD, I don't have that clicking, but it doesn't boot either.

Do the same with a CD (Cube hardware test) in the tray.
 

Also tried PMU reset, button is on the logic board, under the vid card. no joy.

Note it doesn't have PRAM battery. Could it be the problem ?

 

Edited February 20, 2020 by galgot

[Bolle]

There is no chime on the Cube unless you have the original Cube speakers connected.

It will work fine without a PRAM battery so that's most probably not the cause.

 

Lit LED on the logicboard would at least mean it is not a dead VRM. There are however a lot of dead Cube motherboards around that died due to the VRM dying.

Someone might have replaced the VRM after it blew but usually that means the logicboard is gone for good as well.

[galgot]

Thanks. What is and where is located that VRM please ?

The speakers are badly rotten, so I suppose don't working.

There is another led lit when I plug it, green, on the opposite side from the ram slots.

 

Edit: After a bit of cleaning the speakers, there is a chime !

So I suppose the main board is good ?

Edited February 20, 2020 by galgot

[waynestewart]

could be a power supply issue. Does the hard drive spin up after you press the power button?

[galgot]

The original HD makes a clicking noise. I changed it to another empty HD, and yes it spins.

With a keyboard plugged, zapping Pram doesn't work, target mode doesn't work (tried connected to an imac, HD doesn't show). Seems boot keyboard combinations aren't recognised.

Always black screen. Screen power button lit when I start it tho, and if I plug the speakers to the screen usb port I get the chime at start up.