asus p4G533-LA / HP echo4 question

[Lex-]

Hi, this motherboard (Asus P4G533-LA) uses SMD transistors to control the VCC line (+5 volts) of some ports like USB, PS/2 keyboard/mouse, when this line is overcharged or short-circuited due a damaged hardware (keyboard, mouse, printer) connected to one of these ports then the transistor that control or switches this port become damaged, causing that the motherboard can´t "turn-on" USB and PS/2 ports (the motherboard can´t put +5v on these ports), you can verify it seeing that the leds on the keyboard stay off when you turn on the computer...

To repair these motherboards you need to know about electronics specially about SMD, because you need to locate the SMD transitor short-circuited and replace it, I know 3 ways to do this repair:

- Full repair: locate damaged transitor and repace it.

- Partial repair: if yoy can´t obtain a replacement transitor then simply remove it, but the port associated to this transitor will not work anymore.

- Partial repair (improved), you can simply remove the damaged transistor and put a jumper like a SMD cero ohm resistor between collector and emmiter pads on PCB of course, with this "jumper" the port and the motherboard will work without a problem.

Note: The Asus P4G533-LA have 3 of these SMD transistors marked as Q11 (at the back of PS/2 keyboard/mouse port), Q12 (at the back of RJ-45 LAN/ USB ports) and Q21 (near to the USB front panel header). I recommend that you first check Q12, but all 3 can cause these simptoms described by irv6744.

I hope this helps, please post some feedback to know if this procedure helps someone.

Thanks.


Hola tu computadora trae el motherboard Asus P4G533-LA, este modelo de motherboard usa transistores SMD para "accionar" los puertos USB y PS/2 (teclado y mouse), estos transistores funcionan como switches o interruptores que conectan la alimentacion o linea de voltaje de 5 volts de estos puertos, el problema que describes ocurre cuando esta linea de alimentacion se sobrecarga o entra en cortocircuito debido a que algun periferico que conectas a alguno de estos puertos causa este cortocircuito o sobrecarga provocando que el transistor que conmuta esa linea de voltaje se queme, puedes notar si este es el problema verificando que no le llega voltaje al teclado ni al mouse ni a ninguno de los USB (lo cual puedes verificar observando que los leds del teclado no encienden al momento de encender la computadora)...

Para repararla necesitas tener conocimientos y habilidades para trabajar con componentes SMD ya que la solucion es encontrar el transitor que esta en cortocircuito y reemplazarlo, hay 3 formas de "repararla" las cuales son:

- Reparacion total: consiste en conseguir el transistor y reemplazarlo.

- Reparacion parcial: consiste en quitar el transistor que esta causando el problema, esto hace que tu motherboard vuelva a funcionar pero el puerto al que va conectado el transistor dejara de funcionar.

- Reparacion parcial mejorada: en caso de no poder conseguir el transistor puedes colocar en su lugar una resistencia SMD de cero ohms (jumper o puente) entre lo que es el emisor y colector, de esta manera el puerto al que va conectado este transistor seguira funcionando sin problema.

Si vives en Mexico puedo ofrecerte el servicio de reparacion de tu motherboard.

Nota: En este modelo de motherboard (P4G533-LA) he identificado 3 de estos transistores marcados como Q11 (atras del conector de teclado y mouse), Q12 (atras del conector de red RJ-45 con 2 usb) y Q21 (a un lado del conector para los USB frontales). Te sugiero que revises primero Q12 ya que es el que yo he visto quemado en las reparaciones que he hecho pero los 3 transitores pueden causar este problema... Saludos.

[SuperCoolPCGuy]

Thanks for the excellent advice, Lex. Too often I'm faced with having to replace an entire PCB for lack of better alternatives...an electrical engineer I am not. I am but a humble PC repair tech.

Anyway I just wanted to say thanks. Your very helpful knowledge was of great help on this job and (although the USB ports that were dependent on the blown transistor are no longer operable) the machine has resumed normal POST and is running again.

[Platypus]

Yes, I second the vote of thanks to Lex - you never know when information you give may be of use to someone.

[wayno]

Thank you so much Lex. I had the same prob everyone else had.

My daughter pluged a camer into the front USB port while windows was still loading one day. We could never fix it. After reading your post however, I took action popping the Q21 out.

It works again, but without the front usb ports. I can live with that!

Thanks so much for your time and knowledge.

wayne

[wobbles]

hi people,
i am having the same issue with the beeps but here is what i have. a friend of mine has the Pavilion 515x with the same mobo. when her friend stuck a mini usb into the regular usb port on the front of the computer it started to make that beeping sound. can u realy blow a mobo that way? i have never heard of that in all my years of fixing computers. it is a beep like a key is stuck, cant get into the bios at all. if incase that is the mobo that is bad can someone tell me where i can get another one do they still make that board. or should i say the heck and build another computer.

[NooNoo]

Welcome to Windrivers wobbles

Yes you can blow a motherboard that way - inserting it upside down will do the trick, or not pulling it out straight. The contacts on the mini usb will short the usb port out.

Are you using a usb or a ps2 keyboard?

[wobbles]

NooNoo,

hi yes i am using a ps2 mouse. but i can't get anywhere with it. i cant even get into the bios all that shows up is the blue OS screen and it starts beeping like crazy and there is no way to shut it off or get into the computer.

[NooNoo]

wobbles, you should disconnect all hardware except 1 stick of ram and the video card. Find the bios/cmos reset jumper and reset the bios. If it won't clear after that, it's probably toast.

[ceeroo]

i dont have any problems with
beeps or something like that...
I just need some help with a
video driver. My asus P4G533-LA
need it. I had download te audio one
but i dont found the video driver.
plz help me with that driver mi msn...



i want to play RO but i cant because of that driver
plz... someone help me...

Edit by admin: no contact info permitted on the forum, thank you

[CCT]

Download and run Everest Home (it is free):

http://www.majorgeeks.com/download4181.html

Once you download it, click on it and let it install and then run it from the icon on your desktop.

Click on the + sign beside 'Computer', then on 'Summary', then go to the VERY top of the screen and click on 'report'.

Cursor over 'quick report-summary' and then click on 'plain text' and then click on 'save to file' and change the 'save in' folder to 'Desktop' and then click 'Save'.

Clear all your open windows and on the Desktop click on that 'report.txt' icon - this will open it in a text editor
(probably Notepad) and then use your mouse to highlight ALL the 'debug' entries and delete them, then use your mouse to hilight all the remaining text then copy and paste it to here.

For future reference: once you open Everest, click on file, preferences, report and uncheck the 'include debug information in the report' box. People rarely want to see that stuff.

[mcontoso]

I have the same problem - my son has operated with the front USB and he is very sad now. I will try to repair this. But I have no experience with smd - how to do it precisely. When I get back home I will look at the smd transistors - I should cut it out or so? Please tell me some details. In that case it is only problem with Q21 or I have to check the other 2 also. The Q21 is on the main mobo plate or on that part next the front usb sockets. Thanx, i know that is 2008 now, but we still use it (trying to).

[Platypus]

Some information about working with surface mount devices here:

http://poeth.com/smtmfg.htm

If you don't have appropriate soldering equipment and experience, the main risk is damage to tracks and solder pads on the board.

If you can identify that one of the transistors is shorted and preventing the board from booting up, eg by measurement with a meter, but don't have soldering equipment, you may be able to carefully cut the transistor leads using a brand new blade in a Stanley knife. That could achieve Lex's second repair alternative.

[mcontoso]

Thank you for your quick answer - i am reading now - not to destroy to much.
I probably use a blade, but I wonder about the glue under the smd transistor. But it can stay on its place with cuted leads, in the end.

[mcontoso]

Victory, I have fixed it 15 minutes ago.The machine is still alive. I am writing this post on it. I cutted off the Q21 transistor (next to front USB connectors on mobo) and it was that. Thanks a lott LEX, Platypus! and other people for help!

[robertmarq]

gracias Lex- tu informacion me fue muy util y pude resolver un problema con esas caracteristicas gracias x compartir tu conocimiento.