Xbox v1.6 powers on okay, but powers off after 30 seconds...

[grantysid]

Howdy,

So I bought a box of Xbox bits for spare parts which included two Xbox cases, motherboards, one hard drive & one DVD-ROM drive.

The motherboards are both v1.6a boards.

One had a modchip installed by what looked like an arc welder, and the board is now spare parts. I tried repairing the traces, and continuity tested OK but it must have had more damage somewhere not visible as it does the three boots & stops error - after repairing 3 traces I have given up!!

The 2nd board is at least complete but it turns itself off after about a minute of operation. It was missing 2 capacitors, don't know why, but I took them off the damaged board & they are installed OK.

So, I get no errors on startup, it goes to the dashboard, I can select options, even playback music from the hard drive - but then it shuts itself off between 30 seconds and a minute of startup.

Was thinking it could be a power supply issue, but that would be less likely to be intermittent - surely it just wouldnt start at all if it was a PSU problem???

I have tested the transistor by the Xyclops chip, and it is returning a steady 3.29v, so isnt that.

Interestingly, I tried the PSU from other case and it shuts down after around 2 seconds - it has a different Delta PSU to the first one I tried - but both are definately 1.6a boards. Must be less fault tolerant of whatever the problem is.

So, am after any ideas as to what component to try next - I have a whole board full of components to swap over - but it would be nice to be able to start somewhere logical!!

Just to clarify, the board with the power issue has no visible damage - all the components look fine, and the fan is spinning away merrily. Starts no problem, runs fine no errors, can open and close the DVD-Rom tray, controller works fine, and then just turns itself off.....

Any advice would be greatfully accepted!!

BTW - I already have two v1.2 Xbox's (1 with softmod & 1 with mod chip & big hard drive), both running XBMC just fine, networked up to my pc's & the 'net. So this project is just 'playing around'. Am after a 'development' box where I can try out new XBMC builds etc. without having to upset the ones I have already in 'production'.

Should it be that the mobo's are deemed to be toast, I think I have enough extra parts that I can sell off to get a replacement motherboard, but its nice to think I could fix it...

Cheers
Grant.