O2 moosehead audio (and video) module? - Printable Version

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O2 moosehead audio (and video) module? - roach-commuter - 02-23-2021

I opened up my O2's audio module the other day (the 4 plastic clips disintegrated like dry bread in my hands) to an interesting discovery. Half the connectors window was shut closed with some dark/black tape. Below the tape were 4 more "hidden" connectors for seemingly 'composite video' and S-VHS . The module itself has an O2 cam connector in the back, yet when I run 'hinv' it only shows something about the audio.

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RE: O2 moosehead audio (and video) module? - Raion - 02-23-2021

Usually this is because the circuitry for those boards is not setup for video, only audio.

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RE: O2 moosehead audio (and video) module? - robespierre - 02-23-2021

The side connector block for the A/V boards was made as a unit, so all of the connectors are always there.
On the Audio-only boards I have seen, the Philips SAA chips are missing (see attachment). Your board appears to have all of the chips, and also the camera connector, so I'm not really sure why it doesn't appear as an AV1 board. Perhaps there is an EEPROM on the board that causes it to be identified as Audio-only, by changing the PCI identification data?

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RE: O2 moosehead audio (and video) module? - weblacky - 02-24-2021

Wow, that's totally insane. To think it's possible that SGI (possibly at some later point) found it cheaper to produce the SAME components and board and then afterwards neuter it was cheaper than a different board?

Yeah, again as board level repair and investigation gets better with SGI hardware, we may eventually find (through audit) the physical or firmware difference here. It would be a huge thing to find out a sizable population of junk O2 audio-only modules could be retrofitted to full video! One can dream :-)

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RE: O2 moosehead audio (and video) module? - marmotta - 02-24-2021

Yes! Is very strange... the sgi code (030-0728) correspond to A/V module. A photo of another full function module can help.

Another possibility is the module is damaged and the costumer service have disabled the Video function with jumper or another method

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RE: O2 moosehead audio (and video) module? - fleedwood - 02-24-2021

(02-24-2021, 09:15 AM)marmotta Wrote:  Yes! Is very strange... the sgi code (030-0728) correspond to A/V module. A photo of another full function module can help.

Another possibility is the module is damaged and the costumer service have disabled the Video function with jumper or another method

https://bukosek.si/hardware/collection/sgi-o2/img/o2_av1_module_inside_th.jpg

There is D1 (above the left corner of the ADSP chip) missing on your board. That's all I could see

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RE: O2 moosehead audio (and video) module? - roach-commuter - 02-24-2021

What would be the quickets way to debug if video is actually working? I don't have an O2 cam but I coul try plugging something in the RCA composite port. Anything I can run from command line to quickly check if video is ok? EDIT. This machine is running Irix 6.3 I believe.

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RE: O2 moosehead audio (and video) module? - weblacky - 02-24-2021

Well I don’t know about “quick” but I’ve been told when you’re troubleshooting electronics to first look at external interfaces (ports and edge connector interface in this case). Taking both resistance and diode measurements would give you values to compare (assuming you have a working sample and your non-working sample of the device. You measure and compare findings.

Does your audio-only version measure very differently on a few pins? Perhaps those are what indicates what’s supported?

With something like this (and age) I’d assume it identifies itself somehow as different (on top perhaps in actually lacking the functionality). Perhaps it’s like a PCI bus with identifiers or maybe it’s more primitive and SGI purposely disconnected pins and resistors to indicate lack of functionality. I don’t know.

Measurements wouldn’t help you with firmware difference but it would with physical.

After you measure external connectors, you’d then start measurements on internal locations on the board and continue comparisons. Ultimately you’d stop once you’ve probed every component and every solder joint (yeah, lots of probing).

You zero in on any difference as the “supposed” source is their differences.

In theory two identical-looking circuits that measure the same (or similar) under the same tests (in the absence of specialized tests like ASA) should be identical and therefore function identically (less firmware differences).

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RE: O2 moosehead audio (and video) module? - kirikoo - 02-24-2021

You can maybe try the Videopanel program (in the Icons catalog -> Mediatools).
Select composite input and activate live video.
On my O2, when nothing is connected to the composite video input I can see a dark background with some noise.
If I hook a DVD player or camcorder the picture comes up.

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RE: O2 moosehead audio (and video) module? - marmotta - 02-25-2021

I found another one! Module with O2 cam connector but video I/O covered... how many Audio Video modules for O2 exist???

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