Post by: kidacro on April 14, 2008, 10:18:00 PM
Warning: This is a bit nutty
The problem:
You hit the power or eject button on your original v1.6 xbox and nothing happens. Power cords are fine but still nothing... not even a peep.
So you open up the xbox and get out your multimeter. You test the 5v (orange) standby pins on the power connector and your getting the right voltage. You then check the "power-on" pin from the xbox motherboard to ground and your getting some power but not enough (roughly half or less than the standard xbox ATX 3.3v).
You conclude some resistors are dying on you and don't want, or can't replace them, or worst case, don't want to replace the motherboard.
Crazy man's solution:
You can't use the 3.3v lines from the power supply as sources; you need an external source. The less risk way: 2 1.5v batteries in series giving the xbox a "jump start".
Of course the 1st time I did this all I had was a mostly dead 9v battery. Later on in the day I found 2 1.5v "D" batteries which tested good with my multimeter. I immediately stopped testing with the 9v and switched over to the "D" batteries as I figured 3v would be good enough to satisfy the power on signal from the xbox to the power supply. I did notice that the 9v powered up the fan AND the led on the eject button was brighter.
I didnt want to overload the voltage by too much because I didn't know what kind of protection (if any) the power supply had besides the 120v inline fuse for AC input.
On the xbox 1.6 delta power supply, the white wire on the ATX connector gives the "power-on" signal to the power supply, while the blue wire tells the xbox its ready to power up. I connected the positive side of my battery series to the white pin, and the negative side to the xbox chasis as the ground.
Initial Results:
Upon contact, the xbox light on the eject button lit up; pressing the power on button booted up the xbox and I removed the positive wire from the battery series. Everything went perfect.
Of course, once the xbox starts up, the "power-on" pin outputs 3.3v (from standby mode to on), so you don't want to keep the battery connected for very long. This is also why I choose batteries instead of a 3v AC to DC adapter.
Final Modifications:
I inserted a momentary switch between the positive side of the battery series and the "power-on" pin of the ATX connector; leaving the ground wire connected. This gives even a greater feeling of a "jump start".
Eventually I will replace the 2 "D" batteries with a 3v lithium battery and place it inside the case; leaving the momentary switch mounted outside.
Conclusions:
Crazy? Yes!
Safe? Ehhhh, maybe not for long.... im still experimenting.
Working ATM... yes!
The root of the problem is still unsolved. I havent been able to isolate the resistors that are or at least seem to be acting up.
Preface:
The xbox was working perfectly for years... playing over 25 games at random times. At the last time it was working it was on for over 4 hours playing Marvel vs. Capcom 2. The xbox was turned off late at night and had about 7-8 hours of rest. When it was to be used again it wouldn't turn on. It has never been user or factory serviced prior to this (bought new).
Originally I thought it was subject to some form of voltage overload but no physical evidence supported this. There were no burnt out circuits visable or "smellable" anywhere on the power supply, motherboard, or the power/eject switch assembly. Everything was cleaned with many cuetips soaked with rubbing alcohol; no effect.
The power supply was switched out with a verified working one from the same version (but 2 months younger). This yielded the same problems so I concluded the problem wasn't the power supply.
Pictures:
Post by: kidacro on April 15, 2008, 09:34:00 AM
Post by: AfterTheInsanity on April 15, 2008, 10:13:00 PM
Probe the collector. Voltage should be > 3v. If it's less, the transistor is blown. You can replace it a MMBT3906LT1 transistor, either from Digi-Key, Jameco, or Llamma. Or, you can use a normal-sized 2N3906 PNP transistor and rig it to fit (bend the leads and such).