[bkd]

Does anyone know where I can download electric scheme for Octane PSU (first revision, 028-003). I try to recover it but unsuccessful... It seems that it has chain breakage somewhere as it can conduct alternating current but can not conduct direct current. Multimeter shows VERY big resistance but on the other Octane it shows about 500k Ohm. So does on PC (and about that on O2).

[GRudolf94]

There are no schematics for any SGI parts, they were all made under NDAs. Standard SMPS troubleshooting order applies, though:
Input, fuse, varistor, rect. bridge, capacitor, switchers, PWM and transformer, then secondary semiconductors, feedback circuit and output filtering.

[bkd]

Thanks, I try to follow these steps.

[gijoe77]

I've been wondering - its got to be possible to mod a current PC PSU to fit inside an octane PSU - anyone ever think of looking at this? I have, but I just don't have the right sort of tools/gear to figure out what pins have what voltage on that connector. I suppose one would have to get creative with a working octane/PSU to measure those, but I think I see a path...

does there have to be a load to measure voltage pin by pin? have a the common peg of a voltmeter on ground and then measure pin by pin while a modified system is running? If its non-standard voltages add resistors? In my half sleepy state I can almost see this being an interesting project, but only if I knew this side of electronics and tools a bit more...

[bkd]

I think I have somewhere Octane PSU voltages measured by one Nekochan user. I'll search but it won't be too soon.

[GRudolf94]

<QUOTE author="gijoe77" post_id="2273" time="1534070274" user_id="243">

I've been wondering - its got to be possible to mod a current PC PSU to fit inside an octane PSU - anyone ever think of looking at this? I have, but I just don't have the right sort of tools/gear to figure out what pins have what voltage on that connector. I suppose one would have to get creative with a working octane/PSU to measure those, but I think I see a path...

does there have to be a load to measure voltage pin by pin? have a the common peg of a voltmeter on ground and then measure pin by pin while a modified system is running? If its non-standard voltages add resistors? In my half sleepy state I can almost see this being an interesting project, but only if I knew this side of electronics and tools a bit more...

The biggest issue here is finding a PC PSU that will supply rails to the same current an Octane PSU does. Ever looked at the 3.3V IMPACT rail feed posts on the frontplane?

[gijoe77]

what exactly do you mean when you says rails? I'm not really a power guy, but don't modern PSU supply 12V and 5V (or something like that), can't the 5V be lowered down by putting resistors in the path to achieve 3.3V?

[PA8600]

<QUOTE author="gijoe77" post_id="2470" time="1534372207" user_id="243">

what exactly do you mean when you says rails? I'm not really a power guy, but don't modern PSU supply 12V and 5V (or something like that), can't the 5V be lowered down by putting resistors in the path to achieve 3.3V?

A lot of modern PSUs try to put more voltage on the 12v rails than the 3.3 or 5v rails since CPUs and GPUs use those voltages. Even a 1000w PSU will give you what, 25 amps on the 5v rail while they'll put out 80+ amps on the 12v rail.

[jan-jaap]

<QUOTE author="PA8600" post_id="2471" time="1534379023" user_id="121">

<QUOTE author="gijoe77" post_id="2470" time="1534372207" user_id="243">

what exactly do you mean when you says rails? I'm not really a power guy, but don't modern PSU supply 12V and 5V (or something like that), can't the 5V be lowered down by putting resistors in the path to achieve 3.3V?

A lot of modern PSUs try to put more voltage on the 12v rails

amps, not volts.

[Irinikus]

<QUOTE author="gijoe77" post_id="2470" time="1534372207" user_id="243">

what exactly do you mean when you says rails? I'm not really a power guy, but don't modern PSU supply 12V and 5V (or something like that)

Rails refer to Power Supply outputs that feed power to multi-staged circuits. (Amplifiers, for example)


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<QUOTE author="gijoe77" post_id="2470" time="1534372207" user_id="243">

can't the 5V be lowered down by putting resistors in the path to achieve 3.3V?

You would have to make use of a voltage regulator to reduce the voltage from 5v to 3.3V, as the volt-drop across the resistor would result in a huge buildup of heat and would reduce the output current available for the given voltage. (you would more than likely have to run quite a few 3.3V voltage regulators in parallel to supply the required output current.)

<B><U>EDIT:</U></B>

Rather than using multiple voltage regulators in parallel, you could make use of this type of circuit to increase output amperage:


<ATTACHMENT filename="7CIkG.png" index="1">     </ATTACHMENT>


Or this example, if you need even more amps:


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