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No signal going to monitor in Laptop /notebook.

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#1 Maseo


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Posted 30 July 2012 - 09:54 PM

Hi everybody, 1st post here so please bear with me.

model = HP presario CO61

I have a widescreen laptop I am trying to repair for a friend, I do computer repairs in my spare time after work, also gaming console repairs, so I am pretty savvy with most issues, but still need help at times, hence this post.
The laptop has just recently failed to send any kind of signal to the screen / monitor, not even a BIOS splash will come through.

I have tried using 2 other external monitors on the machine, and it's the same - black screen, no BIOS post what so ever.

Have checked the inverter and that works in another machine, so inverter is not the issue.
Cannot test the screen as I don't have a machine spare it will fit into, but Im pretty sure its not a screen issue as the external monitors are not showing any signal either.

Checked cables to back of screen and also on motherboard, all appear in good order and correctly placed.

Have checked overheating issues which could of put the system into a 'coma' ie, non respondent but no reason for it to overheat, chips are pasted nicely, exhaust ports are clean, fan is working.

Usually I would deduce from this that the GPU or southbridge chip has overheated and may have a cold solder, as this is usually the case, but...according to customer, their was no adverse affects prior to this happening.
She said the machine was running fine, no freezing or lock ups, no signs of excessive heat, and that she was just on fac**ook playing a game when the screen went black, and would not come on again.

The power is going into machine, the charging light and HDD activity light both show up on boot, CD ROM resets itself and you can hear the fan and HDD spinning up, so power is getting through, but theirs no sign of the machine actually 'booting' into the OS (win 7 ) as even after 10 minutes or so, the wifi and num lock lights do not show active staus.

so, anybody any thoughts on this please?? If i need to, i will apply moderate heat to the GPU chip to test for a 'cold solder', but I really dont want to be stripping the board out of machine just to do this, and it would not fix it and will only give me the screen back for a short while.
it would then need reballing, if it is indeed the GPU at fault.

So any help or advice is appreciated guys. Sorry for the long post, just thought it better to put as much detail in the 1st post, so as to save everybodys time.

Thanks in advance.

Edited by Maseo, 30 July 2012 - 09:58 PM.

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#2 Platypus


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Posted 30 July 2012 - 11:58 PM

Is it a CQ61?

With the depth of your current diagnosis, it will probably be hard to add much beyond your own suspicion of the GPU. If it's the usual nVidia suspect, then perhaps a re-flow would be successful without having to resort to getting it professionally re-balled?
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