RGH PSU goes red when connected

[midway22]

Hi guys

Modding my 3rd trinity with TX coolrunner, programmed it, installed it flashed ECC to NAND.

However some solder managed to splash on my board, just below the fan connector. It covered the two resistors and the little component labeled USB1.

With a wick and desoldering pump i managed to clean it up but the 360 remain the same.

As soon as i plug in the PSU the the light instantly goes red.


Any ideas?

 

[Martin C]

Did you switch it on with the solder splash there?

 

[midway22]

I never attempted to power on the console till i had the glitch chip in.
After i wired it up the coolrunner, i plugged in the PSU and it went red instantly.

I removed the coolrunner and plugged it back in, went red instantly.

Went over the board, saw the splash, removed it and same thing.

 

[Martin C]

ok - well it means you have a short on the 5V standby rail, more than likely to do with your solder splash. Take a pic of the area and post here.

 

[midway22]

can i link to tinypic?

 

[midway22]

This pics shows exactly what the splash covered before i cleaned it up

 

[Martin C]

silly question, but you don't have your 3v3 and GND cables soldered the wrong way by any chance?

 

[midway22]

Nope, board does not have the TX installed and i tripple check everything before firing it up.
I have done quite a few successful installs on phats and 2 other slims though.

Safe to say the mobo is dead completely?

 

[Martin C]

No not completely dead - you have to see what component on the 5v standby rail is giving you grief. More than likely one of the MOSFETs.

 

[midway22]

how do i go about testing that, none of the mosfets got hit though?

 

[Martin C]

They don't need to be hit. If you have a bridge then any of the voltage regulators on the 5V standby rail could go. It's one of the hardest things to resolve as you need to remove components to test, or look for anything which has blown.

 

[midway22]

Well after looking at the board for a couple of hours i dont see anything popped in that section of the board. So i guess its time i delve into Mosfet replacement :/

 

[midway22]

Martin you weren't joking when you said it was difficult, busy reading up and it seems like quite a feat to do

 

[Martin C]

Yeah, not the easiest of tasks I can tell you.

A multimeter and a hot air rework station would be your best friends about now.

 

[jaymbyrne]

what temperature and airflow would be ideal for lifting mosfets when using hot air rework station ?

 

[Martin C]

You want it running fairly hot, say about 250-300 and mid-low airflow.

 

[peterrepek]

And if you have some other elements really close I suggest you to put a metal ring high about 0,5cm around your mosfet so you isolate your mosfet that you want to desolder and the hot air will not desolder the other components.

 

[jaymbyrne]

what would be best way to refit back on board ? hot air or soldering iron etc .thanks martin .

 

[peterrepek]

If you have a clean surface (without marks of previous solder) use the iron

If not use a combination of both.
First use the iron and then warm a little with the hot air.

 

[midway22]

Martin could you please be a champ and please post what kind of voltages i should be reading on most of the mosfets?