Xbox 1.6 doesn't turn on at all, it seems dead.

[AlanDgamerPROXD]

I've got an xbox 1.6 to be repaired, but i have already checked a lot of things and i can't find the problem.

This xbox was modified to be used as an arcade machine, it used to have a bridge in the HDD's molex conector to the outside of the console, and also it seems all the capacitors had been replaced before. 

The xbox worked normally for a while, and then it just suddenly stop turning on.

I've already checked Q7C2 transistor, the clock capacitor has no leakage, the power button works great and its traces to the Xyclops chip are ok, when i press the button the 3.3V signal goes to 0 (as it should be), but the mother doesn't give the POWON signal, the PSU works great (it gives the POWOK signal to the motherboard, it has no burnt component and when i send a 3.3 signal in the POWON cable, the PSU starts working normally), even i connected a fan to the PSU and it works fine, and when i send the signal, the CPU and GPU heat sinks and the xcalibur chip starts getting warm, but the xbox doesn't turn on. In this state, it gives al the voltages that it should give.

I see that some capacitors were replaced with a Sanyo and SMG capacitors, and all seems to be ok, but i know it is not 100% reliable.

I don't know what else could i check, maybe i'm forgetting something.

Please help
 

[KaosEngineer]

Is the 5Vdc standby voltage level present on the motherboard? (Orange wires)

I believe the Blue connection in the STB column is incorrect.  It too will be 0 Vdc until the power supply turns on.

 

[SS_Dave]

2 hours ago, KaosEngineer said:

Is the 5Vdc standby voltage level present on the motherboard? (Orange wires)

I believe the Blue connection in the STB column is incorrect.  It too will be 0 Vdc until the power supply turns on.

 

On a 1.6 the orange is the standby but without the 3.3 on the PowOk the power supply will fully shut down

The 1.6 PSU supplies a 5 volt pulse on power up then Q7C2 sends a 3.3 volt to the PowOk to keep the supply running then to power on the rest of the PSU you send 3.3 to the PowOn.

When testing a 1.6 PSU out of the Xbox you need to add a load the the 5 volt and 12 volt outputs, The load I use was a Stop/Tail light globe

 

In this pic the Analog meter is set to 10vdc range and is reading 6.7vdc               And in this pic the Analog meter is set to 50vdc range and is reading 11.1vdc

 

Cheers

SS Dave

Soft modding is like masturbating, It gets the job done but it's nothing like the real thing.