[Luke]

Hi, i have an indigo2 here. On power on fans spins for half a second and then nothing happens. I already recapped the psu with no change in behavior. I tried to trace the pinout of the psu, to try it separately in lab but i can't fiugure out how to power it on... i mean on atx you simply connect the green wire to gnd and it works... but here i can't turn it on.

Can someone help ?

I also tried to trace the power on signal from the switch but got stuck on the motherboard just after the riser connector.

Thank you anyway.
Lucas

Edit: These are the voltages i get on the power connetors. They only appear for a second except for the stby that are present. Except for the 3.73stby that is only present after a powerup and keep to be present after fail.

J10

Gnd pin18
Gnd
Gnd
Gnd
+5
+5
+5
+5
Nc
+5
+5
+5
+5
+5.10 stby
+4.90 stby
+4.90 stby
Gnd
Gnd pin1



J11

Gnd pin18
Gnd
Gnd
Gnd
Nc
+12
+12
+3.73
-12
+5.10 stby
-5
+3.5
+3.5
+3.5
Gnd
Gnd
Gnd
Gnd pin1

[GRudolf94]

Greetings

So, by the looks of it, I would guess that your board either has a shorted tantalum capacitor, or something else making the PSU go into short circuit protection. Either that, or something is out of spec on the PSU, and the I2 has a power_good signal that cuts out the PS_ON signal if the PSU doesn't detect voltages to be in the proper range. Your pinout description mostly matches what I found when probing my IP28 with a multimeter (my system came without a PSU). Whatever I found is here: https://forums.irixnet.org/thread-493.html

Does your PSU have colorful wires? The 3.73V signal intrigues me. Could that be the PS_ON signal?

[Luke]

Thank you. I have to do some test to check for correct voltages. I will also xheck for short on tantalum.

Mine psu has colorful cables. It is the impact version with the rigid big flat cable and the impact riser, but with an ip22 board and a extreme graphics.

Dont know why. It worked previously. Then i left it on shelf for a couple month and then when i powered it... you know.

It doesnt have hdd nor cdrom drive. But previously i got to console in eprom and it worked.

[Luke]

Update
After some measuring i ve got some results and considerations:

J10's pin 3 4 are +5v both but with high impedance, they will go down with 220 ohm resistor, so due to the voltage level they can be considered high impedance, so they are probably a digital sensing pis, as power good or something similar, they should probably be tied down to be in the GO state. After shorting to groind it auto recover when load is removed.

J10 pin 5 is clearly the +5v stby power, it have a good strenght. It can supply at least 100mA. It goes permanently down with no auto recovery with a 25ohm load.

J11 pin 9 also is high impedance and auto recover.

Note that both connector are required to power up the unit, this can mean that the sensing and supply are on one connector and the start signal on the other.

If someone with a good unit can check and report whats going on these lines in both on and off conditions it will be of great help.

[Luke]

Ok i made it run without motherboard. Connecting together J10 pin 5 and J11 pin 11 work. But only for a second and with the psu disconnected.

Indigo 2 psu seem to work the opposite respect to atx psu. It need positive voltage to start, while atx need to be connected to gnd.

The sequence is:
Disconnect psu from main line.
Connect the two pins together
Reconnect psu to line
Psu start for a second

I think the psu is gone...

[Luke]

I tried to use an atx psu on the indigo2... and it works. Until a certain point.
I connected only one wire per voltage rail so it can be undersized.

When i start the psu the led turn green, the jingle is played and then the led becomes orange. Then the screen Indigo 2 silicon graphics appear. Then the system make a noisy click, like a relay, and reboot. Sometimes i managed to get in the prom monitor. I got some errors:

Keyboard error, then i connected a keyboard.
Unable to boot. Touch any key... touched a key it rebooted

One time i had time to get to the prom and it seem to function normally.

Voltahe are a bit low. 5v is 4.7 - 4.8 volts i think the psu is cheap, i dont know if this is the the problem.

Toughts ?

[jan-jaap]

Voltahe are a bit low. 5v is 4.7 - 4.8 volts i think the psu is cheap, i dont know if this is the the problem.

Toughts ?

The Indigo2 PSU puts out at least 40A @ 5V if I'm not mistaken. ATX PSUs supply only a couple of amperes @ 5V and the rest of their power mostly into 12V rails. If you are pulling that much current into 5V trough a single wire I'm surprised it didn't melt or trigger an over-current shutdown of the ATX PSU.

NB: my 4D/380 rack has a PSU rated for 200A @ 5V. The little two-wire supply wire to the blinkenlights panel at the front of the system shorted at some point. The wire literally exploded: drops of molten copper and insulation everywhere. The PSU was unharmed

[Luke]

You can weld with that psu.

I will try to find an appropriate connector to connect all the required cables.

Anyway the original psu is rated about 40 amp but this do not means that the computer always drain all that power.

Fortunately my psu is an old 2000 era, when the main rail wasnthe 5v 3.3v and 12v was used just for the motors. It can deliver 46amp at 3.3v and about 35 at 5v and "just" 25 at 12v.
I am trying to discriminate if the problem is the psu or the computer... not an easy task.

[Luke]

It works !

I connected all cables to the respective pins and it works like a charm. So it was a current problem. Still get an orange led for a second after the chime, but then it becomes green again and all goes on well.

Is it normal ? Or can it be cause i didn't connected those signaling pins ? I mean the always on on stby pins +4.9.

Another important aspect, i don't want to cut the original psu connector, should i fix it in the future, so what kind of connector is this ? I tried an half-cutted atx connector but the pin pitch isn't the same...

Do you know ?

[Trippynet]

An LED that is briefly orange is fine. This means that the various power-on tests are running, the LED then turns green once these are passed successfully.