XBox PSU---need help

[Jason4207]

I tried posting at xboxscene, but wasn't able to get any help.

I've done some reading on PSUs and learned I can jump the green (POWON) and black (GND) wires to turn on the PSU. I figured this would work the same with the XBox PSU.

With the PSU plugged in I'm getting 3.3v on the 3VSB (Stand-by). 3.3, 5, and 12 volt rails are in the mV. When I do the green-black jump my rails don't change at all; they stay in the mV. I'm guessing it's dead, but just want a confirmation before I buy a new PSU only to find out it's the mobo. Any help is appreciated.

Here is a link to my xboxscene post .

[Gh3tt0PC]

I'm assuming you know how to use a multimeter, and you're positive you are using the right wires to test? What happened to the PSU that makes you think its dead?

[Jason4207]

Well, I had just bought some wireless logitech controllers for my XBox. I was running xbox media center, and the controls seemed to lock-up. I tried to reboot, but it never came back on.

I've already fixed the PSU once. The XBox was sparking, and that led to me getting the free power plug from M$ with ground fault protection. I was still getting sparks, though, so I cracked her open again. I then noticed where the soldered leads coming in from the power plug input had desoldered themselves from the PCB. I cleaned it up, and resoldered everything very well. My fix was working great for a good while until recently.

Looking at the PSU now, my soldering has held up. So, I'm not sure of the problem now. When I press the power or eject button, the GPU fan spins for a second and then stops. None of the lights on the front of the XBox light up at all. The lights on the Logitech tranceivers also light up for a second when either the power or eject button is pressed on the XBox.

I wanted to test the PSU, so I took my multimeter to it. The 3.3v stand-by (3VSB) is putting out a steady +3.3v, so no problem there. I read that jumping the green (POWON) and black (GND) wires will trick the PSU into turning on (at least on a PC PSU). I jumped them and verified the jump w/ an audible continuity test. None of my rails responed to the jump. They all started with readings in the mV, and stayed there after the jump. I also have a 92mm fan plugged into the molex connector to provide some load, and act as immediate confirmation that juice is flowing.

I'm assuming that since the jump didn't work that the PSU is dead, but I don't know for sure. I'm hoping it is the PSU because otherwise I'm guessing it has to be something of the mobo.

The PSU looks fine. None of the caps are bulging or anything. I'm not sure where the fuse on it is, but I'm guessing it's OK because the 3VSB line is still hot.

Thanks for your help.

[TDOGZZ]

i can,t help with your problem.. but i,m going to fix my nephews xbox tonight because it sparked at the psu/side of the plug.

after reading abit i,m assuming it,ll be the same prob as most of them and it,ll be bad solder pts on the power input leads(hopefully the sparking didn,t blow the psu)

EDIT:it was the power input solder joints and i resoldered the one black(bad) and loose connecter ,then powered it up and it sizzled again and it broke(melted)the remaining leg so it now won,t reach the original solder pad...after i get the ok from my nephew tommorrow i,ll add a sony ps2 power plug and socket(from a parts ps2) and solder the wires directly to the top of the xbox psu pads.

(the black plastic plug port must of been ruined on the bottom side of the psu circuit board,i knew it was black but i thought it was just smoke/heat damage and not physically in bad shape)

[Jason4207]

Yeah, my black plastic plug port appears to be fine because I'm still reading 120v further up the traces on the PCB.

If someone could just run an experiment for me I'd appreciate it. Remove the PSU from the XBox. Place a jumper between the green and black wires, and then plug it in. Then test your rails to see if you're getting 3.3v, 5v, and 12v on them. If you are, I know my PSU must be bad because that is what I did except my rails didn't turn on. Thanks.

[TDOGZZ]

did you go back to a regular controller or no controller to make sure it wasn,t the cordless ones causing the probs?(i assume you did but you never know sometimers)

if the xbox was mine i would of checked for ya but i couldn,t try jumping my nephews without actual pinout facts incase those 2 points shorted it out or something.

just info :i ended up using 2 x 2" of wire to go from the black plug(installed on the outside of the xbox w/hot glue) and the psu solder headers and it worked fine...the trace under the original bad solder joint lifts up abit though.

[Jason4207]

Yeah, i've tried it with the standard controller, and no controllers...no dice.

I tested the green wire (powon), and it is reading -3.3v. When I jump it to ground it (as it should) goes to ground.

Anybody got any ideas, or is anyone willing to run the experiment above?

Thanks.

[Grandtete]

Wire the xbox to a spare atx psu. If the xbox works its the xbox psus fault. Simply solder a molex connector the xbox motherboard, or solder the atx psu to the mobo etc etc

[superdude101]

you actually wouldnt need to solder anything since the mobo itself has the proper connections

[Jason4207]

Thanks for the advice. Here is what I did. I have an old ATX PSU, but since I have a v1.0 XBox, the connectors are not directly compatable. I started cutting wires, and then did some soldering. I soldered the powon, powok, 3.3, 5.5, and 12v lines from the ATX to the Xbox connector. I tied the ATX ground to the Xbox connector, and to the Xbox PSU. I left the 3.3v stand-by hooked up to the Xbox PSU because the ATX has a 5v stand-by.

I plugged in the ATX. The Xbox immediately came on without pressing any buttons, but the light was orange. Then I realized I had forgotten to plug in the Xbox PSU (Doh!).

I started over, and plugged in the Xbox PSU 1st. Then I plugged in the ATX PSU, and the Xbox immediately came on again. This time the light didn't light up at all, but the fans kept spinning. That is until I press either the power or eject buttons. Then the Xbox cuts off, and won't come back on. If I unplug both plugs, and start over I get the same results.

Another very strange thing I noticed before I began all this cutting. I had the Xbox PSU hooked up to a 92mm fan, so I could easily see if it came on, and to provide some load. I plugged in the Xbox PSU, and was checking it with my trusty mutimeter. When I put the jumper between the green and black wires nothing happened as usual. I started to pull the jumper out, and the fan started spinning...very slowly. It turns out that if I take a jumper and touch the green wire with one end, and just grab the other end of the jumper that the PSU starts putting out some juice. It is very inconsistent power, and my rails are jumping all over the place. I'm not sure why this phenomenon is occurring, but it is interesting nontheless.

I'm sure my Xbox PSU is bad now. I'm going to order a new one. I just hope I didn't fry my mobo with all this experimentation. Thanks guys.