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[fr_dr]

So does anyone know where to get a replacement for this chip (i mean elsewhere then a working mobo) or if these chip are all the same on every version from 1.0 to 1.6, so I could get my hand on a broken xbox (non FRAO of course   ) and try to change it to see if it solve my FRAO board problem...

[thedominor]

QUOTE(Dallas186 @ Oct 20 2005, 04:46 PM)

Hi Guys,

swapping the chip off of the working board (very carefully) and soldering it onto the non-working board solved the problem , 3.2V on pin 5 and the box booted normally.
Now if any of you guys that know far more about the Xbox than i ever will can identify what this component is I too would be mucho grateful!!
I took a photo of that part of the board when comparing the 2 boards side by side and have reference to the voltages at most points around that area and resistor values from the working board if you would like me to post it.
strange thing was R7R8 read 47k on the non working board and 20k on the working board (ummmm)
I hope this helps anyone else that is showing low V on pin 5.
Best,
Rich

sweet that is so awsome.  Other than being an IC, i couldn't tell you what that chip is for.  But it sounds like this is the fix we've wanted...too bad I already installed my new mobo   oh well, it is still good to know.  Thanks!  I wonder if pimplex has some extra boards he could try this with?

QUOTE(fr_dr @ Oct 20 2005, 04:59 PM)

So does anyone know where to get a replacement for this chip (i mean elsewhere then a working mobo) or if these chip are all the same on every version from 1.0 to 1.6, so I could get my hand on a broken xbox (non FRAO of course  ) and try to change it to see if it solve my FRAO board problem...

No idea about the chip being the same, but if I pull my 1.4 out of my box, I will compare it with my busted 1.0 and see if they look identical. as for where to buy and mobo, check the Buy/Sell/Trade forums.

[ferrari_rulz_02]

well does that chip have any numbers on it? if it doesnt, then the only place you will get another one from is off another mobo

[Dallas186]

QUOTE(Dallas186 @ Oct 20 2005, 10:46 PM)

strange thing was R7R8 read 47k on the non working board and 20k on the working board (ummmm)

Hi,
decimal point missing, sorry 4.7k is the correct value for the resistor R7R8, reading 2.0k was more than likely pulldown from something else.

just going back to this IC for a second, Iv'e got a theory that it's actually a dual transistor in SOT-28 format.


I have now also bought a (repaired-now working) 1.4 board and can confirm that the component is the same on version 1's and V1.4's so it's a fair bet that the component is common to all versions though this is a hunch.

I'm tempted to pull this component off the 1.4 board and see if i can work out what it is (wish me luck)

can anyone else with the FRAO problem just confirm that they see low voltage on pin 5 of the LPC and the SAME voltage on pin 6 of that 'IC' at least then it shows a theme to the problem and not that the FRAO just means that a component has gone duff and could in fact refer to ANY component as was so eloquently described in an earlier post...lol

that would really help me.

Best,
Rich

[PimpleX]

You mean changing this q7r1 IC fixed it after all??:



I just figured I must be barking up the wrong tree when I considered it to be that, then because the traces mostly go to the MCPX I figured it must be there instead due to likely heat failure LOL...I will have a go at swapping one over soon.

Cheers,

PimpleX

[ferrari_rulz_02]

well Dallas186, let us know how you go

[Dallas186]

QUOTE(PimpleX @ Oct 21 2005, 12:37 PM)

Hello, what's all this then?

You mean changing this q7r1 IC fixed it after all??:

I just figured I must be barking up the wrong tree when I considered it to be that, then because the traces mostly go to the MCPX I figured it must be there instead due to likely heat failure LOL...I will have a go at swapping one over soon.

Cheers,

PimpleX

Yes, i'll almost guarentee that if you can change Q7R1 for a known good one then you will regain 3.2v on pin 5 of the LPC, whether that would will cure your FRAO problem remains to be seen but i WOULD love to know.

when i get home i'll compare your voltage readings with the ones i took on the duff IC before it was changed out.

Rich.

[PimpleX]

Ok I changed it on my v1.1 and yes I get good volts on the LPC now, ....but still 0.0v on the MCPX and it FRAGS.

Volts on the MCPX look much better during 3 boot attempts though than they did previously, but still 0.0v after the 3 boot attemts. Whereas "normal" FRAgging boards have 3.3V on the MCPX I'm pretty sure I tested for before now and that's right,.... correct me if that's wrong though.

There are also two more of these ICs the same markings on top of the board, one near the MCPX and one near the TSOP,..... I've measured the volts on them and the one near the TSOP gives almost the same readings as the q7r1 IC on the same board, so make an easier measuring point to check I think. However I'll try that all again just to make sure that's correct. There are also two flavours of this IC that I've found so far, one like the photo above looks like MA-I the other looks like MAk, still not enough info to look anything up about them though...

This was really fiddly to change mind and I made a bit of a mess of it to be honest (about 5 x harder than the 1.6 tranny change I'd say) and I had to redo it twice LOL and you have to get it the right way around. Mind you I'm using an ordinary 18w soldering iron and tip, nothing fancy, I think I'll put wires on the next one and solder them to the pads instead for a more "certain" result.

I'll try it again on my v1.0 FRAO which is now FRAG but still with 0.0v on the MCPX also, but i'll take measurements on the bare solder pads and try it without the IC before putting on the new IC just to see what might happen.

What does this IC do then you think?

Cheers,

PimpleX

[ferrari_rulz_02]

QUOTE(PimpleX @ Oct 22 2005, 12:47 AM)

What does this IC do then you think?

i think it was said before. its a dual transisitor

[Dallas186]

PimpleX,

yeah, nightmare ain't it

Weller all the way for me. 60W and a .75mm tip

works a treat.

Rich

[Dallas186]

Hi again guys,

ok, done a lot of thinking/searching/head scratching on this one and FINALLY sorted it!!

the component in question is indeed a dual transistor of the NPN flavour, it's a MBT3904DW1T1 manufactured by 'Motorola' and the format is SOT-363. Basically it's a dual 2N3904 general purpose signal transistor.

you can grab the datasheet for it here

from the datasheet we get that

Pin 1. Emitter Q1
Pin 2. Base Q1
Pin 3. Collector Q2
Pin 4. Emitter Q2
Pin 5. Base Q2
Pin 6. Collector Q1

this now all makes perfect sense!

just to prove the point i did a bit of a test using actually 2 BC337's as it's the nearest i could find to hand, soldering them onto the motherboard in place of the blown MA IC and it worked, booting into the dashboard without any problems.

it's not pretty but proves the point!!



Tomorrow i'm going to try and buy some proper MBT3904DW1T1 IC's.

but really this is not a noob fix, soldering these in place on the MB is a complete nightmare and just heating them for a fraction too long blows them, so although not pretty the 2N3904 or indeed BC337 alternative is really actually easier and only cost 13p each! it's just working out where to solder each leg that's tough

To determine if it's this chip that has blown (which incidentally caused a FRAO on my V1 and a FRAG on a V1.4) test the voltage on pin 5 of the LPC, if it's less than 3.2v then this is the problem. to further determine do a search on the web for 'testing a transistor using a DVM' though you will almost certainly need to desolder the IC to thoroughly test it anyhow.

I hope this helps those that are suffering with this problem

Best regards,

Rich.

[ferrari_rulz_02]

wow. finally a solution to this damm problem.

if we can get some more people with this problem to try this, it would be great.

this NEEDS to get pinned or soemthing

[Dallas186]

Hi again,

ok here's where we are, have ordered 50 MBT3904DW1T1 IC's (minimum order quantity) so if any of you guys need a couple of these PM me your postal address and i'll mail a couple to you, guys who posted in this thread before i got involved in this problem can have two or three free of charge, ok?

As this is a special order thru RS (in the UK) it's going to take between 3 and 8 days to get them so don't think iv'e forgotten about you.

obviously if there is a lot of demand then i may have to consider a very small paypal contribution to cover postage but i'm not out to make money on this.

US residents should be able to buy this IC themselves as from past experience your availability on components is FAR better than for us in the UK where if your'e not trade then you can't buy (sad but true) though more so on specialist components such as this one, having said that if your'e in the US and struggling to find this component then i'm sure i can work something out for you.

I hope this has helped you. as i'm probably going to be asking some 'daft' questions about mod dashboards/hacked bios'/flashing etc. in the near future and don't want to be laughed at..

My best regards,

Rich.

[ferrari_rulz_02]

thats very generous of you Dallas186.

i hope we can see if this fixes some more frao boards

but obviously the million dollar question now is......why do they blow in the first place?

[Dallas186]

hey no worries, mate.

Why do they blow? interesting question. although i have no data as yet to substantiate this i am starting to think that the box has an inbuilt 'life expectancy' its not unusual for manufacturers to do this, washing machines are designed to last about 5 years on average for example. it's a method that is employed to keep the manufacturer in business by ensuring constant demand. Sony did this with the PS2 by running their lasers very much 'on the limit' though their motherboard is bulletproof by comparison to the Xbox from what i have seen so far.

The MBT3904DW1T1 will tolerate 200ma draw, for how long is debateable, you see where i'm going with this?

as this is a slightly unusual component and difficult to source and replace for your average bod and that is even if he or she could find the fault it stands to reason that this is perhaps one of the components to pick for engineered life expectancy.

I have to be a little careful on slating MS though as if you were to cut me in half it would probably say 'M!crosoft' in the middle. I won't elaborate on that one.

Best regards,

Rich.