SGI: Hardware

Does an Onyx2 have an internal speaker? If so, where is it?

I didn't think it would but when running apps that use audio, certain sounds cause my Onyx2 to emit a nasty crackling noise. The workstation never emits any other sounds, such as boot chimes. (Other than fan noise, of course!) It doesn't matter if I have external speakers plugged in or not. External speakers do work properly with this machine.

Only certain clangy/crashy sounds do this, for example, when a tank is shot in bz or pretty much any sound when flying around in vroom . At first it sounded like electrical arcing but it seems more likely there's a ripped speaker cone somewhere in the chassis.

I thought someone here might know something before I tear the thing apart to find it.

Guess this is my month to ask SGI audio questions!

Trust me there's no internal speaker in an Onyx2. And the sounds you're hearing might be your power supply.
This could get nasty... Either replace it, or have the capacitors replaced by a professional.
Or on a lighter note, there might be something loose making contact with the fans in the fan tray

My old octane power supply would click violently during some operations, mainly anything that took a lot of HPs or time to redraw would cause the machine to click in sync with the screen redraws. That power supply has been recycled...

It could be fun to see which programs cause the noise and how to trigger it. Then you can pin down where the problem is. OTOH you should probably just repace it.

Heh I really think it depends on resource loads, still easier to open the PSU, head down to your local electronics store
or radio shack. I fixed my second Ony2's PSU that way... cap discharge can be painful though lol

Hmm, OK. I'll do some troubleshooting before giving up on this PSU. Whatever the cause of the noise, it doesn't seem to be directly related to system load (i.e. current draw from the PSU). Running something CPU- and graphics-intensive like SkyRocket doesn't trigger the noise. So far, I have only observed that playing certain sounds correlates with it.

If it really is arcing, I'm surprised it's not causing other problems. Typically, a brief arc discharge causes a very large inductive spike that affects DC voltages throughout the system, not to mention a sudden voltage drop on the net that's arcing. But the system just keeps humming along.

Ryan, you said that you repaired one of these PSUs. Do you have any tips on troubleshooting it? Were you able to probe test points somewhere while it was running to look at the output voltages? Can the power supply be run on a bench by itself?

It is almost certainly not arcing. You need to figure out where the noise is coming from. It could be something like a choke where the epoxy cracked and now vibrates. Who knows maybe there actually IS an internal speaker in the onyx2 ?

I should make a recording of some of the sounds my alphastation 600 makes. Now that is a machine I will not leave running unattended

I had some time to work on this today. The sound is definitely coming from the IO6G, from a few cm behind the audio in/outs. I'm pretty sure it's coming from one of the relays in the picture below. For some reason, bz and vroom cause at least one of them to continuously toggle.

It's not just due to the sounds, either. I went into vroom 's data directory and tried playing the sound files directly using soundplayer and they play fine without making the noise.

Another clue may be that this machine can't record decent audio from the microphone port. It turns my voice into an 80s synthesizer with distortion cranked up to the max. I haven't tried the audio line in yet.

Any idea what these relays are for? I thought they might switch between the various audio ports, but the contacts don't seem to connect to any of them.

Does the song Intergalactic come to mind?

FWIW, I've heard this same kind of noise on my Onyx2 as well.

So, I started my octane up last night for the first time in a little over two weeks and it made a horribly disgusting screech for the first 2-3 seconds or so and then climbed in pitch until I could no longer hear it. Then the breaker tripped because I forgot to turn off the heater first This is the new cherokee, it could well just be the first time starting it without music playing and it always does that... Ran all night and this morning with no problem.

The old-style supply definitely clicked, mainly when running programs such as bzflag or glx-rss savers. It stopped when I upgraded to a v6.

Do you think the relay is actually stuck or do you think the relay is fine and it is just turning on/off rapidly for some bizzare reason?

It's turning on & off rapidly. Here's a 5 sec audio clip I recorded of it while running vroom : (taken by my Indigo2)

http://www.gelhaus.net/irix/io6g_clicks.aiff

It's clearly not coming from the power supply, so my system isn't about to die an imminent death, but it's really annoying.


That sounds like a bad ball bearing in the power supply fan.

I highly doubt just changing out the relays will solve the problem, they must have DC coils. (I have heard relays with AC coils make similar noises when they are stuck)

Have you tried checking the sample rates in the audio control panel to see that they are all the same as what vroom is outputting? It could be that maybe vroom wants the hardware at 32khz (for example) but it is set at 44.1 khz, and vroom can't change this automatically.

Now that I think about it, it sounds like a sample rate problem...

The relays are NEC/Tokin EB2-4.5NU miniature signal relays, and they have 4.5V DC coils and non-latching contacts. The datasheet was easy to find. I used very similar relays on a board at work a couple of years ago, and they sound exactly the same. People would come to my cube to find out what the racket was when I was testing a microcontroller routine that cycled all 128 relays one by one.

According to the audio panel, vroom is setting the sample rate to 16kHz. This matches the Indigo2. It locks me out while running the game and I can't change it, although I can when vroom isn't running.

Digging up one of my old threads. I recently obtained a second IO6G for a price I was willing to pay, and swapped it into my Onyx2. It also does this loud annoying clicking, and I really can't conceive of an explanation for other components in my deskside causing loud audio clicking on an IO6G. My conclusion is this must be some sample rate issue or the way that vroom and couple of other programs interact with the audio hardware.

I haven't tried recording with this new IO6G yet to see if that works any better, so maybe I'll try that when I get some spare time.

FWIW, I've noticed this too and also tracked it down to relays on the IO6G.

I also assume it's some audio-modeswitch glitch.

I never got beyond this...