[khral]

A few week ago, I decided to do some experiment with PowerAnimator's particle systems (hair and fur stuff) on my Indigo2 after it last use months ago, then my Indigo2 give off a pop sound followed by burnt electronics smell few second after it was turned on.

Turned out it cause by shorted tantalum capacitor (C57) on audio board which also took an inductor (L517) along with one of it's pad. Luckily my Indigo2 work after I took out the broken audio board.

       
The picture of damage

After replace the inductor with salvaged parts from old computer motherboard (from USB power filter portion) and replace the shorted 47uf 20v tantalum capacitor with 100uf 16v Rubycon ZLH capacitor (the lowest capacitance parts I currently have), the audio board was working again.

Preferably the replacement should have the same capacitance and voltage, but since the replaced capacitor was for power line of audio board, it probably not cause problem using higher capacitance, I think. (feel free to correct me that)

       
Faulty parts replaced

I also search the internet to see if there was other people have same problem with their audio board and was it a common issue, and have found one case at https://www.okqubit.net/machines/sgi.html on R8000 Indigo2 that have not turned on for months, and the burnt tantalum capacitor is at same place, so this might be common issue.

I think it might be worth to check tantalum capacitors on Indigo2 audio board, especially C57 for short circuit if the Indigo2 haven't been turned on for many months. Or better replace C57 (or all tantalum capacitor on audio board) with new capacitor, just in case.

[weblacky]

Thanks for posting this, it would be nice if someone with a proper LCR meter could measure that inductor for us so a suitable replacement could be found. I don’t own such a device.

Seems like perhaps after PSUs, mainboard shotgun recaps may become the thing. Given how hard it is to test tantalums in place, it might be easier to just replace then strategically (with known, good power too).