Asante MacCon Ethernet Card Causing No Startup

[Kevinlenane]

Hi I have a common Asante MacCon Ethernet card that came in an SE/30 originally stacked on top of a Diimo. The Diimo is missing two caps but when I plug the card into the PDS slot (the logic board was just recapped by me) - the entire machine just clips, clicks and won't power on anything including fan. The caps on the card look fine and the Iogic board works perfectly without the card in. Has anyone experienced a MacCon card fully disrupting the power on process. Tried w multiple PSUs and saw same issues as well. If the card was shorted by a monitor plug in it's past - what would need to be replaced? Fwiw it also happens w and wo the daughter card connected.

 

[halkyardo]

The complete failure to power on with the card installed points to a shorted power rail. The SE/30 MacCons that I’ve seen have a pair of tantalum capacitors in one corner - these sometimes fail short-circuited, either with spectacular fireworks (which at least makes the problem obvious), or just loading the power supply down enough to cause it to shut down. In the latter case there’s no way to tell visually that the capacitor is faulty, you’ve got to remove it and test its resistance.

I’ve had a few pieces of old electronics develop this kind of fault. I wouldn’t call it a hugely common problem but it’s the first place I’d look given the symptoms you describe.

 

[Kevinlenane]

The complete failure to power on with the card installed points to a shorted power rail. The SE/30 MacCons that I’ve seen have a pair of tantalum capacitors in one corner - these sometimes fail short-circuited, either with spectacular fireworks (which at least makes the problem obvious), or just loading the power supply down enough to cause it to shut down. In the latter case there’s no way to tell visually that the capacitor is faulty, you’ve got to remove it and test its resistance.

I’ve had a few pieces of old electronics develop this kind of fault. I wouldn’t call it a hugely common problem but it’s the first place I’d look given the symptoms you describe.

I've had the wildly blown version once so I didn't think that was the issue - I think I still have these caps so I'll try this. Thx!

 

[cheesestraws]

Agreed: if it's clicking and nothing is happening even the fan, that means the PSU is failing to start up, which is probably because of a short.

 

[Kevinlenane]

Agreed: if it's clicking and nothing is happening even the fan, that means the PSU is failing to start up, which is probably because of a short.

Thx both - I was looking for those popped caps but it's good to know they may fail quietly and w o fanfare.