Fixing the X-BOX 360 Power Supply

In Mother's Day, May 11, 2008 a power surge in the Allegheny Power feed took out my X-Box 360 Power Supply. Here are some pictures of the damage. Here is the place where the Transient Voltage Suppressor got fried. The fuse also popped. I removed the fuse and the two Transient Voltage Suppressors from the board to take the picture. The Transient Voltage Suppressors were encased in heat shrink tubing.

Allegheny Power tells me that there was no abnormal voltage conditions associate with the outage that day. My next door neighbor had the surge protector for his TV blown. My neighbor upstairs had two TVs blown out. In addition to my XBOX power supply, I had a TV fuse blown. When I replaced the fuse, the TV still didn't work.

Here is another view of the damaged area.

Another view of the damaged area.

Here's the fried Transient Voltage Suppressor. It was so badly damaged that it cracked in half.

There are two TVS on in the X-Box supply. Presumably, one is on each power leg. The other leg was not fried. Here's the label side of the "good" TVS.

TVS Characteristics

Part Number:	TVR 104241
Normal Varistor Voltage:	240
Allowable Maximum Voltage, VAC(rms):	150
Allowable Maximum Voltage, VDC:	200
Maximum Clamping Voltage (8/20uS), Vp:	395
Maximum Clamping Voltage (8/20uS), Ip:	50V
Max. Surge Current (8/20uS), Imax:	4500 A
Max Energy (10/1000 uS), Wmax:	63 W
Rated Power (W):	0.6 W
Reference Capacitance, pF:	580 pF
Thickness (mm):	4.9 mm

Digikey Equivalent Part

Fixing the Power Supply

If you choose to do what I did in the following steps you need to know that I take no responsiblity for the outcome. If you catch your house on fire from this fix, it's not my responsiblity. Only try this if you are completely confident in the solution for yourself. I am only telling you what I did for my power supply and not suggesting that you do the same for yours. You need to know how to solder without making solder bridges to do this.

TVS Replacement

I purchased a handful of the digikey TVS parts and replaced the one that blew out plus the other one - just in case it was damaged. I enclosed the TVS parts in heat shrink tubing and shrunk the tubing down to size to fit. Near as I can tell the purpose the of heat shrink tubing is to contain the fire should one start. I probably should have used fire resistant heat shrink tubing. I had an assortment of tubing from Harbor Freight. I also had a heat gun that I bought from Harbor Freight.

Fuse Replacement

Here's a picture of the original fuse next to a mm ruler. Looks like it should be replaced with a 20 mm long fuse. Digikey sells fuses that match that size and I should have probably bought one of them. Not sure if they sell leaded fuses or if these are endcaps? Are they soldered on or press fitted?

I bought an 8A slow blow fuse at Radio Shack (Catalog #: 270-1030) and replaced the fuse. I had to solder leads onto the Radio Shack fuse to match the original part. The original was in heat shrink tubing so I enclosed mine as well.

When I went to put it back together it didn't fit well. The reason was that the original fuse had a smaller body size so I moved the fuse to the side slightly to fit. Here's the Radio Shack fuse next to the original fuse. Maybe the caps would desolder and could be reused? They look smaller than the Radio Shack fuse ends.

Assorted Notes

I kept all of the assorted parts in a ziplock so that I could put the power supply back together again when I was done. The screws that hold the power supply case together were under the rubber feet.

There is a webpage which suggests replacing the internal fuse with an external fuseholder. This probably could be done safely. I bought one and the leads were really thick and by the time I shaved down the wires to fit into the holes on the board I didn't feel that it was a safe solution. If there was a commonly available fuseholder with smaller gauge wires it would be a pretty good idea (other than the safety concerns). My fear is that a kid would find it irresistable to open the fuse holder and the terminals are spring loaded which would leave electrical hot in a dangerous place. Might work encapsulated in heat shrink tubing, though.