SGI: Hardware

I'm messing with the hardware configuration of redbox and I've noticed that the PSU crackles a bit when I insert the power cable and that I can only start the machine after the crackling settles down.

As I know very little about hardware, I'm assuming this is normal operation and that the crackling is caused by (maybe) the capacitators 'filling up' with electricity?

if you mean that you insert the power cable into the psu socket while the other end is plugged to a wall socket, what you hear is totally normal, and happens to all psu.
Usually is better to plug the cable in the psu, and only after, to plug the other end in the wall socket, to prevent unfortunate accidents

Is this crackling, the same as the clicking that proceeds Fuel power supply death?

Well, maybe it's the pre-death clicking then... after I insert the cable into the PSU, for about 2-3 minutes there's a very soft 'crackling' to be heard coming from the PSU. During this time the PSU does not switch on. After a while the crackling subsides and then the PSU switches on without any issue.

It only happens after the PSU has been disconnected from the wall socket. Cycling/start/stopping the machine without removing the lead from the wall doesn't affect the machine.

Sounds ominous...

The front stages of PSU's tend to be perminently powered, even when the computer is switched off - this is to allow electronic control of the PSU. Only unplugging the PSU from the mains/wall socket or using the mechanical switch will de-energise these stages. There is a lot of electrical stress on the PCB and these front end components, which could result in strange sounds (crackings, hissings, clicking). What you are hearing is probably the result of the PSU 're-stressing' as the mains voltage is re-applied.

In my experience these things rarely get better and ultimately lead to some form of catastrophic failure, but it is sometimes worth getting a vacuum cleaner out and removing as much dust and debris from the PSU as possible, as this all increases the probability of electrical breakdown within these high stress stages.

Cheers, Adam

Rhodamine wrote: In my experience these things rarely get better and ultimately lead to some form of catastrophic failure

In this oddball case, this is a good sign. The death-march for Fuel power supplies is the irreplaceable cheap-ass little SGI chip that turns them on.

The power supply itself could explode, but as long as that little interface chip is okay there's probably a hundred dead Fuel power supplies to cannibalize. Heck, I had two myself I'd have contributed, but got tired of them cluttering the place up.

hamei wrote: The power supply itself could explode, but as long as that little interface chip is okay there's probably a hundred dead Fuel power supplies to cannibalize.

Very true, as long as the PSU has decent crow-bar protection and doesn't blow anything when it goes, then they are probably one of the 'easier' parts to replace/fix.

I'm not familiar with the specifics of Fuel PSUs or their failure mechanisms, but sounds like a bit of a design flaw.

Cheers, Adam