Print Page - 360s No Power.

I was given a 360S (Trinity) with the RDOD.

Did the usual and checked all the cables and PSU and all seem OK.

Tested the PSU on my other 360S (Corona) and powers up fine.

Originally the console would power on from the front touch panel with the RDOD but the fan didn't power up and the PSU light stayed amber.

One time i powered it on and the red light came on but the green ring of light started up as normal but with no A/V. Since then the console will not power on from the front panel, but when the power or eject button is pressed
you get the audible power and eject noise. (IMG:style_emoticons/default/uhh.gif)

it powered up a few times after this with a wired controller but still had the RDOD.

Now it refuses to power on from the wired controller. The controller will just flash like when the controller isn't synced with the console.

I couldn't find alot of information on this issue or was to resolve it.
I did read this could be related to either a defective RF board or a damaged mosfet?

If it is the mosfet, where would i start?

I have fixed a fair few RROD on the phat consoles but i haven't worked on a Slim before and am fairly new to
removing components and testing them so bare with me.

Any help is greatly appreciated.

Heres a picture of my Trinity
(IMG:http://i45.tinypic.com/24fjs46.jpg)

And a video before the console refused to power on.
http://www.youtube.com/watch?v=_TOUuLVjURg

hey ... you might try to search for a short to Ground. Check all the power rails to Ground with Continuity.

3.3 v to ground , 5 v to ground, 12 volts to ground

You could have a short in a Mosfet or a Power Regulator. Or maybe a Resistor failed. It appears that you might have 16 Mosfets on that board. Or at least 16 devices with a DPAK package style.

Google - (Image)- Dpak package .... that will help you slightly identify some things

Mosfets have to removed from the board to be tested for failure. I recommend using a Hot Air Tool from a work station and some flux

Hello Wilgo45

Thanks for the advice

Like i said, i personally don't know much about testing mosfet or power rails.

if you're able to write up a n00b friendly points to test and how to test them that would be appreciated and might help others having similar issues (IMG:style_emoticons/default/smile.gif)

Maybe include a few pictures?

I can get a better picture as this was a quick snap off my Blackberry.

I dont have a work station but can get my hands on a hot air gun?

Other then that all i have is a low watt soldering iron and a friend that's a dab hand with soldering and has a pretty good knowledge on testing electrical components, sadly he has no knowledge around xbox's.

Sorry to be a pain

This post has been edited by ray123454321: Jan 6 2013, 11:07 AM

I'm pretty sure a motherboard will boot up with no ROL board connected, using wired controller. So try that to rule out bad ROL.

Most likely I think it's a shorted fet or defective cap. There's many posts on help with troubleshooting mosfets. Start from the power connector, check your 12 rail and see if it's shorted (zero ohms to ground). Most people will tell you fets need to be removed to test but you can test by lifting the two legs. A simple tester with ohms and diode check is all you need. If you can't find a short start inspecting the big caps, check soldering on bottom, I have had a Falcon here with badly soldered caps.

This post has been edited by relaxxx: Jan 6 2013, 02:57 PM

You can try swapping the ROL board. If it individually has a short; it might keep the whole console stalled. If that is the case; there are ICs on the ROL board that can be changed out. To make it live again

If that's not the case, then I'd almost bet it the 3.3 volt reg. I think there is a history of problem there with some certain Slims.

And just to ask again - to rule it out - the Power brick ? ... will it power another Slim just fine ? I have come across Power Bricks that will sort of work. There issue will be one line of 12 volts is down

This site has pages for it somewhere. But you can just Google - sources of voltage for Slim 360 motherboard. Like I had said, this might really help. Paint a clearer picture

Keep me posted

I have a similar problem with my XBOX 360 slim the original power supply is showing a red light.
Just to be sure i bought a new power brick its showing a orange light.

Opened the xbox on the mother board its only reading +5v ( 4.97 ~ 4.98 ). No other voltages show up

QUOTE(xbox360hardware @ Jul 21 2013, 02:39 PM)

I have a similar problem with my XBOX 360 slim the original power supply is showing a red light.
Just to be sure i bought a new power brick its showing a orange light.

Opened the xbox on the mother board its only reading +5v ( 4.97 ~ 4.98 ). No other voltages show up

Is your Slim stock ? Or modded with a Glitch board?

QUOTE(wilgo45 @ Jul 22 2013, 06:08 AM)

Is your Slim stock ? Or modded with a Glitch board?

The mother board has never been modified

These are some could be's to your situation.

First power brick might have had a shorted device. 2nd brick might not be the correct one. There are 10.8 amp and 9.8 amp for the Slims.

Other potential problems ... with the internals on the console

A dead mosfet. Shorted Power Reg. Issue with ROL board.

First thing to try. Disassemble your Slim. Or mainly - just take the motherboard out of the cage. Re-assemble things outside of the cage ... and go for a power on.

I have come across some consoles that short to ground against their cage. Just as simple as that. Outside of the cage will power on. Then you just have to insulate the point of contact.

However ... if you like - I do repairs

QUOTE(wilgo45 @ Jul 22 2013, 04:06 PM)

These are some could be's to your situation.

First power brick might have had a shorted device. 2nd brick might not be the correct one. There are 10.8 amp and 9.8 amp for the Slims.

Other potential problems ... with the internals on the console

A dead mosfet. Shorted Power Reg. Issue with ROL board.

First thing to try. Disassemble your Slim. Or mainly - just take the motherboard out of the cage. Re-assemble things outside of the cage ... and go for a power on.

I have come across some consoles that short to ground against their cage. Just as simple as that. Outside of the cage will power on. Then you just have to insulate the point of contact.

However ... if you like - I do repairs

I have Disassembled the whole XBOX 360 measure voltages according to
( http://xbox-experts....-xbox-360-slim/ )

Only +5V is present. ( Look at the bottom view )

QUOTE(wilgo45 @ Jul 22 2013, 04:06 PM)

These are some could be's to your situation.

First power brick might have had a shorted device. 2nd brick might not be the correct one. There are 10.8 amp and 9.8 amp for the Slims.

Other potential problems ... with the internals on the console

A dead mosfet. Shorted Power Reg. Issue with ROL board.

First thing to try. Disassemble your Slim. Or mainly - just take the motherboard out of the cage. Re-assemble things outside of the cage ... and go for a power on.

I have come across some consoles that short to ground against their cage. Just as simple as that. Outside of the cage will power on. Then you just have to insulate the point of contact.

However ... if you like - I do repairs

Any circuit diagram showing the Mosfets ( Location ) ? Power regulator (Location )?

QUOTE(xbox360hardware @ Jul 22 2013, 07:55 AM)

Any circuit diagram showing the Mosfets ( Location ) ? Power regulator (Location )?

If you have 5v standby present, but no power on. A power reg is probably shorted.

The very same document you linked for voltages; has rough descriptions on topside device voltages.

A lot of the dpak package devices are Mosfets. But other will be power regs. Like U4E1 - probably a Power Reg. U1C1 - another Reg.

You need to find your short. Whether between 12v and GND ... or 5v and GND or one of the other rails

QUOTE(wilgo45 @ Jul 22 2013, 08:45 PM)

If you have 5v standby present, but no power on. A power reg is probably shorted.

The very same document you linked for voltages; has rough descriptions on topside device voltages.

A lot of the dpak package devices are Mosfets. But other will be power regs. Like U4E1 - probably a Power Reg. U1C1 - another Reg.

You need to find your short. Whether between 12v and GND ... or 5v and GND or one of the other rails

I have +5V present on the Board.

No shorts on U4E1 all three legs show no shortage to ground.

U1C1 has one leg that reads short to ground ( Bothways 0 ohm) . Just where it reads U1C1

ONLY +5V is present on the board.

QUOTE(xbox360hardware @ Jul 23 2013, 01:58 AM)

I have +5V present on the Board.

No shorts on U4E1 all three legs show no shortage to ground.

U1C1 has one leg that reads short to ground ( Bothways 0 ohm) . Just where it reads U1C1

ONLY +5V is present on the board.

Actually stanby voltage is really low not close what the diagram says.

One leg of Q5B1 should give +5V it reads Zero. Not sure if that actually means that Device
is shorted. Do you know if that is a Problem ?

According to the diagram for Q5B1

The drain portion of the Mosfet should have 5v standby present. The drain side is both the large tab in back and the broken leg in the middle on the front.

Double check your metering readings please

You're not reading the voltage diagram very well

With U1C1 ... both the Gate and Source legs are to Ground. So reading from GND to GND is going to give you 0.0 ohm - the meter is always going to find the most simple route. Its probably not reading thru the device, but from pad site to pad site - since both are GND

You follow ?

While you are looking things over .... Check on your 0 ohm resistors. They appear to be marked 0000. Or just 0. And there appears to be 7 large ones. Check them with continuity or resistance. They act like fuses - for circuit protection. If one was knocked out to save the system - then that route is still down

This post has been edited by wilgo45: Jul 23 2013, 02:40 AM

QUOTE(wilgo45 @ Jul 23 2013, 06:38 AM)

According to the diagram for Q5B1

The drain portion of the Mosfet should have 5v standby present. The drain side is both the large tab in back and the broken leg in the middle on the front.

Double check your metering readings please
You're not reading the voltage diagram very well

With U1C1 ... both the Gate and Source legs are to Ground. So reading from GND to GND is going to give you 0.0 ohm - the meter is always going to find the most simple route. Its probably not reading thru the device, but from pad site to pad site - since both are GND

You follow ?

While you are looking things over .... Check on your 0 ohm resistors. They appear to be marked 0000. Or just 0. And there appears to be 7 large ones. Check them with continuity or resistance. They act like fuses - for circuit protection. If one was knocked out to save the system - then that route is still down

1. Q5B1 has no +5V checked it again

2. Which Voltage reading is incorrect ?

U1C1 only one leg is shorted to ground. which i told yesterday.

All seven 0 Ohm resistors are working

QUOTE(xbox360hardware @ Jul 23 2013, 04:52 AM)

1. Q5B1 has no +5V checked it again

U1C1 only one leg is shorted to ground. which i told yesterday.

Please don't get snippy. I've been trying to help you. The only one here in fact

If you have 5v standby on the board back near the power plugin - then that's good. If the brick is producing Standby - then it can be ruled out.

The power diagram by Xperts might be when power is enabled.

As for FETs and transistors, they can't always be tested accurately while still soldered to the board. Most reliable testing is off board.

First step might be to remove your Inductor coils. Then test for shorts to GND between the different power rails.

But for a 360 not to power on .... likely sources are the Power Regs, ROL board or the Cpu chip

QUOTE(wilgo45 @ Jul 23 2013, 08:38 PM)

Please don't get snippy. I've been trying to help you. The only one here in fact

If you have 5v standby on the board back near the power plugin - then that's good. If the brick is producing Standby - then it can be ruled out.

The power diagram by Xperts might be when power is enabled.

As for FETs and transistors, they can't always be tested accurately while still soldered to the board. Most reliable testing is off board.

First step might be to remove your Inductor coils. Then test for shorts to GND between the different power rails.

But for a 360 not to power on .... likely sources are the Power Regs, ROL board or the Cpu chip

Thanks for your help. I am just answering your questions. Which may lead to no where but any
way thanks for the response.

First i have only +5V , according to the diagram standby is produced on the board by circuitry. That is
my understanding and from this i infer that standby is not being generated.

I understand the confusion caused by semi-conductor devices while testing them on board. But usually
a short is quite obvious and can localized with the help of circuit diagram.

There are no shorts between the Power rails. I did check that its the first step when you have issues
of voltage not being present.

Desoldering component is risky and i have to be 100 % sure before i touch it.

Now you are saying that the CPU might cause a reset so that the +12V does not come up and bring all the circuitry up.
How do i check that ?

Second is does the CPU control Standby voltage in any way ? because i dont have standby voltage ?

According to the Xperts diagram standby should be 3.3 V

I am not saying that the Cpu is your exact problem. Just that it can be a source of a No Power situation. But the least likely.

Cpu does not produce standby voltage. The brick does. And I said nothing about reset and Cpu - so don't know where you are getting that from

So remove the Cpu from your mind.

If you have no Standby present anywhere in the motherboard .... then you have a bad power brick

5v is the standby. 3.3v can be found present with the 5v. A main power reg processes the 5v standby to a 3.3 .... both will be present .... 5v is the main

If you are finding 3.3v on your board - then you are getting fed the 5v in a proper manner

In order to know that you have a short to GND from say 12v or 5v rails .... is to remove the Inductor coils

Desoldering is not that risky. Good equipment makes all the difference. You'll want 60/40 solder and a nice gel flux. I have removed and replaced hundreds of Mosfets.

If you have had trouble with desoldering, then your iron is too weak. Either wrong style tip or not hot enough. Lead free has a higher melting point. Plus the ground plane is thick on a 360

A single plug iron won't do the job. You'll need a Soldering station. One with a Hot air tool makes removing multi legged transistors easy.

I'm stepping away from this topic. Good luck

This post has been edited by wilgo45: Jul 23 2013, 09:43 PM

QUOTE(wilgo45 @ Jul 24 2013, 01:41 AM)

I am not saying that the Cpu is your exact problem. Just that it can be a source of a No Power situation. But the least likely.

Cpu does not produce standby voltage. The brick does. And I said nothing about reset and Cpu - so don't know where you are getting that from

So remove the Cpu from your mind.

If you have no Standby present anywhere in the motherboard .... then you have a bad power brick

5v is the standby. 3.3v can be found present with the 5v. A main power reg processes the 5v standby to a 3.3 .... both will be present .... 5v is the main

If you are finding 3.3v on your board - then you are getting fed the 5v in a proper manner

In order to know that you have a short to GND from say 12v or 5v rails .... is to remove the Inductor coils

Desoldering is not that risky. Good equipment makes all the difference. You'll want 60/40 solder and a nice gel flux. I have removed and replaced hundreds of Mosfets.

If you have had trouble with desoldering, then your iron is too weak. Either wrong style tip or not hot enough. Lead free has a higher melting point. Plus the ground plane is thick on a 360

A single plug iron won't do the job. You'll need a Soldering station. One with a Hot air tool makes removing multi legged transistors easy.

I'm stepping away from this topic. Good luck

Thanks for the response. Desoldering is on expensive side when you dont know the actual problem.

As for my take on the subject is that the power brick gives a +5V to the mother board , it gives a power good
signal to the brick then it switches the +12 V , So we have +5 and + 12 V fead to the mother board.

Again there is no 3.3 v on the mother board ?

Over here the brick is giving +5 V and the mother board is not giving back a power good status. Not sure why ?

I have tried two power supplies.

So still in the unclear area where the problem is, its big mother board ?

Thanks any way

This post has been edited by xbox360hardware: Jul 23 2013, 11:06 PM

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