[Gllug] Precision M65 screen - horizontal lines ... ut oh :|

[general_email at technicalbloke.com]

On 27/05/11 00:47, 'lesleyb' wrote:
> On Thu, May 26, 2011 at 08:40:34PM +0100, Alistair Mann wrote:
>> 'lesleyb' wrote:
>>>  Hi everyone,
>>>
>>>  I have a Dell Precision M65 with horizontal lines appearing on the
>>>  left of the screen.  They extend from the screen edge to 1 Gkrellm
>>>  width where GKrellm width=110.  They extend the full height of the
>>>  screen with some flicker on the lines.
>>>
>>>  These lines appear at switch on so I suspect this is not a driver
>>>  issue.

Hi Lesley,

It could be any of 3 things, GPU, LCD or screen cable...

The artefacts not appearing on the external monitor output doesn't
guarantee the fault isn't with your GPU chip*, it makes it perhaps a bit
less likely but it is still a possibility. The GPU chip is also the most
expensive thing to fix so I would try to eliminate the other
possibilities first.

Dells are extraordinarily fussy about their screens otherwise I would
suggest you bring it over to mine and try a generic LCD panel in it (90%
of 15" laptop LCD panels are interchangeable). It does sound like the
panel is probably your problem though.

Genuine LCD panels for Dells tend to cost upwards of £80 but most
vendors accept returns with a small restocking fee so as long as you're
very careful not to mark the new panel you can order one and send it
back if it doesn't fix your problem. In fact, as a consumer you can
always return any product bought online within 7 days for a full refund
under the EU distance selling regs so if you're feeling bolshy you can
even tell them their restocking fee is illegal!

The only other thing it could be is the screen cable. I doubt its that
if the lines are flickering but often these are available on ebay for
£10 or thereabouts so if you want to diagnose it yourself this would be
the cheapest part to eliminate.

If, after all that, it does turn out to be your GPU then make sure
whoever you take it to for repair either "reballs" the chip or uses a
brand new chip with leaded solder balls (technically no longer legal in
the EU but you can get them from China :) There are a lot of repair
places (the vast majority) that simply "reflow" the chip which is a
crappy fix that is likely to go wrong again within a few months and
leave your machine in a worse state than before. Similarly there are
number of places that claim to do reballing that are full of s***. If
they won't guarantee their work for over 3 months I'd stay well clear,
also if they are too cheap be worried, a proper reball will cost over
£100. If you struggle to find someone you can always drop me a mail, I
have a guy who does reballing and he guarantees the fixes for 6 months,
he's trade only though and it would cost £165 so it's often only worth
it for fairly high end laptops - yours being 5 years old I'd put that
money towards a new machine.

Hope this helps,

Roger Heathcote - technicalbloke.com

* People tend to assume a laptop's external monitor port is simply an
electrical split of the output to the LCD panel. If that were the case
my life would be a lot easier! A typical modern BGA mount GPU may have
over 400 individual solder pads on it's underside. A laptop's VGA, DVI
or HDMI sockets all have their own output pins separate from the ones
that go to the LCD panel so breaks in those joins can affect each output
independently. Not only that some laptops can output a different picture
to their external outputs which implies they have separate framebuffers
and GPU circuitry for each screen so... while it IS the case that if you
get lines on your external monitor output AND your LCD you DO have an
ailing GPU the inverse isn't true, having a perfect picture on the
external out doesn't mean you don't have dodgy solder joins on the
underside of your GPU or electrical faults within your GPU that are
affecting the picture on your LCD panel :/

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