Strange PC Video Fault

[Java Jive]

This is a deliberate cross-post concerning a presumed hardware problem.

This happened on turning on this laptop this morning, it's a Dell
Inspiron 15RSE 7520:

www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg

The pattern is rather unusual. In the past, nearly always I've seen
video faults that concern one of the primary colours ...
Dead red = cyan (turquoise) cast
Dead green = magenta (purple) cast
Dead blue = yellow cast
... but this patterning is rather different.

And it's not constant, but changes over time, for example it changed
somewhat as I moved the mouse, and in fact for a while now it's gone
altogether. I suspect that temperature may have played a part in its
appearance immediately on switching on and its subsequent disappearance
as the PC warmed up, a loose connection possibly.

Or the screen or the video card is dying.

Does anyone recognise the rather unusual patterning and can be more
specific in their diagnosis?

[sticks]

Post by Java Jive
This is a deliberate cross-post concerning a presumed hardware problem.
This happened on turning on this laptop this morning, it's a Dell
  www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg

I get this


Hmm. We’re having trouble finding that site.

We can’t connect to the server at www.macfh.co.uk.

[Paul]

Post by Java Jive
This is a deliberate cross-post concerning a presumed hardware problem.
  www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg
The pattern is rather unusual.  In the past, nearly always I've seen video faults that concern one of the primary colours ...
  Dead red = cyan (turquoise) cast
  Dead green = magenta (purple) cast
  Dead blue = yellow cast
... but this patterning is rather different.
And it's not constant, but changes over time, for example it changed somewhat as I moved the mouse, and in fact for a while now it's gone altogether.  I suspect that temperature may have played a part in its appearance immediately on switching on and its subsequent disappearance as the PC warmed up, a loose connection possibly.
Or the screen or the video card is dying.
Does anyone recognise the rather unusual patterning and can be more specific in their diagnosis?

Intel HD 4000 Integrated graphics and AMD Radeon HD 7730m

There are various reports of issues with these specific Radeon graphics. You are not alone.

Radeon HD 7730M April 2012 GCN 1st gen (28 nm) 512:32:16:8 2GB GDDR3 128 bit
(Chelsea LP)

So that could be a chip with four RAM soldered to the top, 512MB GDDR3 chips with 32 bit interfaces.
RAM come in 8 bit, 16 bit, 32 bit versions, and can share
a common ball pattern on the bottom. So the 8 bit RAM, 24 signals
would be "no-connect". That sort of thing.

The effect might stop, if you turn off the AMD graphics.

The way the two GPU "share", is one GPU makes an image and
dumps it into the shared system RAM the other GPU uses, and
it displays the contents of that shared area. Only one GPU
drives the TMDS cable (likely the Intel HD 4000), and if/when
the AMD is running, the software changes the pointer location
to the frame buffer the TMDS-driving GPU is using.

Occasionally on an AMD, there is a fabrication issue with the
mounting of RAM over top of the GPU chip.

But your pattern is not suggestive of a recognizable pattern.
It's not uninitialized RAM. The pattern for that is filled with
"more rectangular constructs". Your image looks like a photograph
previously occupied the memory, and now is being displayed in false
colours.

I don't know how they do scaling on panels, if at all. Maybe
a panel with a TMDS cable, only runs native ? And everything
else is fudged via GPU ? Regular LCD monitors can have scalers
to support multisync (a scaler chip can fail). And panel electrical
driver failures, make lines on the screen. Pixel rows or pixel columns.
The pattern is not a match for a panel problem.

I'd say the AMD GPU is croaking, and it should be switched off.
It could be a cracked ball on the bottom of the fine pitch BGA
AMD chip, or a problem with the solder between the AMD chip
and the complement of RAM riding on top of it.

All that (logically) switching it off does, is removes software
usage of it. If the thing had an electrical problem, it could
burn whether logically on or logically off. It could be an
intermittent connection (cracked ball). Or even one of the
four RAM chips on the lid, is failing (thermally induced failure
or mechanical pressure induced failure). They have fancy ways
of packaging silicon today, that are much more aggressive
in terms of causing problems (HBM near some GPUs, die height).

Some laptop GPUs are MXM style. There is a conventional GPU
and it is surrounded by RAM chips, similar to how a PCIe card
does it. MXM can be unplugged. But they're high power devices,
merit a separate blower, and the laptop sucks down battery
so bad, you leave those plugged in at your desk. That's an example
of a laptop GPU you can repair, by replacing it. Your machine
might need a hot air station, to fix.

Whereas the dual-GPU mid range laptops, there can be
a soldered down GPU chip. Does not take nearly as much X-Y space
inside the chassis. Needs a heatpipe for cooling. And if there
is VRAM (it does not absolutely need to have VRAM), sometimes
the packaging method leaves a bit to be desired. Just the way it was
soldered and underfilled at the factory, could be part
of the (eventual) problem.

heatpipe ---------------> heat to blower area
RAMx4 (quadrants)
GPU
(underfill)
PCB

A laptop which only had the HD 4000 graphics, would be
pretty useless for gaming (SIMS level), but it would
have the benefit of being less failure prone.

The AMD GPU is 25-28 watts (listed in Wikipedia). And that would
be flat out, with a tail wind. Furmark thermal rating. GPUs
from that era are not closed loop control, which is why
the usage of Furmark had to be detected manually and
the driver would turn down the clock :-) That's to prevent
thermal mayhem. Both CPUs and GPUs today, have power limiters.
We may not like the settings they used for those power limits,
but, they have power limits. Like your desktop 4090 at 450 watts
or 600 watts. That sort of thing.

Paul

[Java Jive]

Post by Paul

Post by Java Jive
This is a deliberate cross-post concerning a presumed hardware problem.
  www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg
The pattern is rather unusual.  In the past, nearly always I've seen video faults that concern one of the primary colours ...
  Dead red = cyan (turquoise) cast
  Dead green = magenta (purple) cast
  Dead blue = yellow cast
... but this patterning is rather different.
And it's not constant, but changes over time, for example it changed somewhat as I moved the mouse, and in fact for a while now it's gone altogether.  I suspect that temperature may have played a part in its appearance immediately on switching on and its subsequent disappearance as the PC warmed up, a loose connection possibly.
Or the screen or the video card is dying.
Does anyone recognise the rather unusual patterning and can be more specific in their diagnosis?

Intel HD 4000 Integrated graphics and AMD Radeon HD 7730m
There are various reports of issues with these specific Radeon graphics. You are not alone.
Radeon HD 7730M April 2012 GCN 1st gen (28 nm) 512:32:16:8 2GB GDDR3 128 bit
(Chelsea LP)
So that could be a chip with four RAM soldered to the top, 512MB GDDR3 chips with 32 bit interfaces.
RAM come in 8 bit, 16 bit, 32 bit versions, and can share
a common ball pattern on the bottom. So the 8 bit RAM, 24 signals
would be "no-connect". That sort of thing.
The effect might stop, if you turn off the AMD graphics.
The way the two GPU "share", is one GPU makes an image and
dumps it into the shared system RAM the other GPU uses, and
it displays the contents of that shared area. Only one GPU
drives the TMDS cable (likely the Intel HD 4000), and if/when
the AMD is running, the software changes the pointer location
to the frame buffer the TMDS-driving GPU is using.
Occasionally on an AMD, there is a fabrication issue with the
mounting of RAM over top of the GPU chip.
But your pattern is not suggestive of a recognizable pattern.
It's not uninitialized RAM. The pattern for that is filled with
"more rectangular constructs". Your image looks like a photograph
previously occupied the memory, and now is being displayed in false
colours.
I don't know how they do scaling on panels, if at all. Maybe
a panel with a TMDS cable, only runs native ? And everything
else is fudged via GPU ? Regular LCD monitors can have scalers
to support multisync (a scaler chip can fail). And panel electrical
driver failures, make lines on the screen. Pixel rows or pixel columns.
The pattern is not a match for a panel problem.
I'd say the AMD GPU is croaking, and it should be switched off.
It could be a cracked ball on the bottom of the fine pitch BGA
AMD chip, or a problem with the solder between the AMD chip
and the complement of RAM riding on top of it.
All that (logically) switching it off does, is removes software
usage of it. If the thing had an electrical problem, it could
burn whether logically on or logically off. It could be an
intermittent connection (cracked ball). Or even one of the
four RAM chips on the lid, is failing (thermally induced failure
or mechanical pressure induced failure). They have fancy ways
of packaging silicon today, that are much more aggressive
in terms of causing problems (HBM near some GPUs, die height).
Some laptop GPUs are MXM style. There is a conventional GPU
and it is surrounded by RAM chips, similar to how a PCIe card
does it. MXM can be unplugged. But they're high power devices,
merit a separate blower, and the laptop sucks down battery
so bad, you leave those plugged in at your desk. That's an example
of a laptop GPU you can repair, by replacing it. Your machine
might need a hot air station, to fix.
Whereas the dual-GPU mid range laptops, there can be
a soldered down GPU chip. Does not take nearly as much X-Y space
inside the chassis. Needs a heatpipe for cooling. And if there
is VRAM (it does not absolutely need to have VRAM), sometimes
the packaging method leaves a bit to be desired. Just the way it was
soldered and underfilled at the factory, could be part
of the (eventual) problem.
heatpipe ---------------> heat to blower area
RAMx4 (quadrants)
GPU
(underfill)
PCB
A laptop which only had the HD 4000 graphics, would be
pretty useless for gaming (SIMS level), but it would
have the benefit of being less failure prone.
The AMD GPU is 25-28 watts (listed in Wikipedia). And that would
be flat out, with a tail wind. Furmark thermal rating. GPUs
from that era are not closed loop control, which is why
the usage of Furmark had to be detected manually and
the driver would turn down the clock :-) That's to prevent
thermal mayhem. Both CPUs and GPUs today, have power limiters.
We may not like the settings they used for those power limits,
but, they have power limits. Like your desktop 4090 at 450 watts
or 600 watts. That sort of thing.

Thanks for your extensive research, but I'm coming down on the side of
it being the display. See my imminent reply to Char Jackson.

[Char Jackson]

Post by Java Jive
This is a deliberate cross-post concerning a presumed hardware problem.
This happened on turning on this laptop this morning, it's a Dell
www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg
The pattern is rather unusual. In the past, nearly always I've seen
video faults that concern one of the primary colours ...
Dead red = cyan (turquoise) cast
Dead green = magenta (purple) cast
Dead blue = yellow cast
... but this patterning is rather different.
And it's not constant, but changes over time, for example it changed
somewhat as I moved the mouse, and in fact for a while now it's gone
altogether. I suspect that temperature may have played a part in its
appearance immediately on switching on and its subsequent disappearance
as the PC warmed up, a loose connection possibly.
Or the screen or the video card is dying.
Does anyone recognise the rather unusual patterning and can be more
specific in their diagnosis?

I have the same model of laptop, in continuous 24x7 service since early 2012. No
video issues so far.

What would you think about temporarily connecting a second display to the
laptop*, with the idea being that it may help to determine whether you have a
display panel issue or a GPU issue. I would think that a panel issue is a bit
more likely.

*There should be an HDMI connector and a VGA connector on the left side. I use
VGA to drive a second display, but I've used HDMI in the past and it also works
fine.

[Java Jive]

Post by Char Jackson

Post by Java Jive
This is a deliberate cross-post concerning a presumed hardware problem.
This happened on turning on this laptop this morning, it's a Dell
www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg
The pattern is rather unusual. In the past, nearly always I've seen
video faults that concern one of the primary colours ...
Dead red = cyan (turquoise) cast
Dead green = magenta (purple) cast
Dead blue = yellow cast
... but this patterning is rather different.
And it's not constant, but changes over time, for example it changed
somewhat as I moved the mouse, and in fact for a while now it's gone
altogether. I suspect that temperature may have played a part in its
appearance immediately on switching on and its subsequent disappearance
as the PC warmed up, a loose connection possibly.
Or the screen or the video card is dying.
Does anyone recognise the rather unusual patterning and can be more
specific in their diagnosis?

I have the same model of laptop, in continuous 24x7 service since early 2012. No
video issues so far.
What would you think about temporarily connecting a second display to the
laptop*, with the idea being that it may help to determine whether you have a
display panel issue or a GPU issue. I would think that a panel issue is a bit
more likely.
*There should be an HDMI connector and a VGA connector on the left side. I use
VGA to drive a second display, but I've used HDMI in the past and it also works
fine.

Unfortunately I have no alternative display. My external monitor caught
fire some years ago and I never replaced it.

However, I think you're right, because a number of things that I've
observed during the course of the day all seem to point to the display:

- If I disable the AMD Radeon HD 7730M as Paul suggested, there is
no change, the screen still shows the effect.

- When the display has been on for a while it seems less likely to
show the problem, but when it has been blanked by the screensaver for a
while, it's more likely to show the problem immediately after being
turned on by moving the mouse or typing.

- But the killer diagnosis is this: if I alter the angle of the lid,
all hell breaks loose until I stop moving it!

So now I must decide whether I think it's worth trying to source
another, probably used, display and attempting to fix it ...

:-( Unfortunately, these clam shell laptops are a PITA to take apart
and repair. Usually, changing a laptop display is a relatively quick
job, because the lid will be held on by a small number of screws, and
usually the display is connected under the keyboard and the WiFi and
other possible aerials connect to the card(s) either also under the
keyboard or else under an easily removable bottom cover - often the
trickiest part is simply getting the aerial cables to feed through a
small hole or cutout to get them beneath the motherboard - all of
which means that you can just buy a lid/display as a unit off a used PC
that has failed somehow else, and swap it easily with your broken one.
However on these buggers you have to remove the palm-rest and the bottom
of the case, lots of screws, and lots of other things to disconnect on
the way and to forget to reconnect as you re-assemble it - that may
even be why I now have this problem, because I went through all that to
change the fan 10 months ago, though I rather think it's actually the
display screen itself rather than the connector, because the hinges are
so tight that every time you open or close the lid it flexes slightly,
and given the events of the day, I'm now suspicious that this flexing,
over the years I've had the PC (from new), is the root cause of the
display giving up.

:-( Also, it's quite a limited screen resolution, and, having had to
replace already two of the Dell Precision M6300s with their lovely big
screens within about 6 months of each other, I now have two Dell
Precision M6700s both of which are higher spec than this, and, although
they don't have the same height resolution as the 6300s, the better of
the two does have a higher screen resolution than this, so I was
planning to turn it into my principal PC anyway.

:-( Also, the Inspiron's speakers are knackered.

:-( Also, it can't fit into a dock as can the 6700/6800/etc series.

So I think I might just let it go. Can't complain, if it's worth
nothing now, it works out that it's cost me £69pa in depreciation, and
that seems reasonable to me.

[Andy Burns]

Usually, changing a laptop display is a relatively quick job, because
the lid will be held on by a small number of screws, and usually the
display is connected under the keyboard and the WiFi and other possible
aerials connect to the card(s) either also under the keyboard or else
under an easily removable bottom cover  -  often the trickiest part is
simply getting the aerial cables to feed through a small hole or cutout
to get them beneath the motherboard

All the ones I've seen, have cables running through a "tunnel" in the
hinge, there's usually a video on youtube for each model ...

[Java Jive]

Post by Andy Burns

Usually, changing a laptop display is a relatively quick job, because
the lid will be held on by a small number of screws, and usually the
display is connected under the keyboard and the WiFi and other
possible aerials connect to the card(s) either also under the keyboard
or else under an easily removable bottom cover  -  often the trickiest
part is simply getting the aerial cables to feed through a small hole
or cutout to get them beneath the motherboard

All the ones I've seen, have cables running through a "tunnel" in the
hinge, there's usually a video on youtube for each model ...

Yes and no, it depends on the model, let alone the make. Dells vary
considerably by model. See my other replies here.

[VanguardLH]

Post by Java Jive
- But the killer diagnosis is this: if I alter the angle of the lid,
all hell breaks loose until I stop moving it!

That could be a ribbon cable that has worked loose. You would have to
dismantle the case to extract and reinsert the ribbon cable to ensure
any oxide on the foils got wiped off.

Dell Inspiron 15R SE 7520 Take Apart Complete Disassemble

Shows more than just disassembly of the shell that you would need to get
at the ribbon cable from mobo through hinge to display panel. Takes
several screws to remove (better than notebooks that you need a spludge
to pry apart the tangs used to snap together the shell halves).

If you don't feel like doing all the work, and hoping you get it all
back together again (without some extra parts left over afterward),
check with a computer shop what they would charge on reseating the video
cable in the mobo and in the PCB for the display. If the laptop is
still viable and wanted, $120 USD might be worth having a shop do the
repair as opposed to applying that money to a new laptop. Sometimes it
is worth the cost savings, sometimes not.

To check if it is the display panel or ribbon cable, don't rotate the
lid. Get it in a position where the display looks good, and twist the
lid in place. The connection from the lid PCB to the display could be
just a piece of rubber with metal traces that gets sandwiched to make
contact, and rubber, silicone, or other plastics shrink with age. That
would require taking apart the display module at which point it might be
worth the added effort to replace the CCFLs (cold cathode fluorescent
lamps aka backlamps since those fade over time). Often you can find
kits with all the parts, including butyl tape, to repair the display
module.

Post by Java Jive
:-( Also, the Inspiron's speakers are knackered.

Whatever that means. If you decide to repair (instead of trash), you
could inspect the speakers when dismantling.

That one shows replacing the speakers. Looks like you have to buy a
custom speaker module from Dell.

[Java Jive]

Post by VanguardLH

Post by Java Jive
- But the killer diagnosis is this: if I alter the angle of the lid,
all hell breaks loose until I stop moving it!

That could be a ribbon cable that has worked loose. You would have to
dismantle the case to extract and reinsert the ribbon cable to ensure
any oxide on the foils got wiped off.
Dell Inspiron 15R SE 7520 Take Apart Complete Disassemble
http://youtu.be/AivcRqtS76A

Yes, I followed one of those in the past when I changed the fan, but
it's not a ribbon rather a round cable ...

Dell Inspiron 15R Owner’s Manual*

p35 Removing the Display Assembly

Prerequisites
1 Remove the battery. See "Removing the Battery" on page 13.
2 Remove the keyboard. See "Removing the Keyboard" on page 15.
3 Remove the base cover. See "Removing the Base Cover" on page 17.
4 Remove the palm rest. See "Removing the Palm Rest" on page 27.

p27 Removing the Palm Rest

Prerequisites
1 Remove the battery. See "Removing the Battery" on page 13.
2 Remove the keyboard. See "Removing the Keyboard" on page 15.
3 Remove the base cover. See "Removing the Base Cover" on page 17.

Procedure
1 Remove the screws that secure the palm rest to the computer base.
2 Turn the computer over.
3 Lift the connector latches and pull the pull-tabs to disconnect the
power-button board cable, touchpad cable, and hot-key board cable from
the connectors on the system board.

[11 screws and three connectors over and above what you've already
removed to get this far, then 'spludge' - perhaps that should be
'kludge' - the palm-rest off the base, and only then can you access
the hinge screws and the display and WiFi connections.]

Incidentally, this is a model where only an option made at purchase time
included an extra card connector on the underside of the daughterboard
for the card slot(s), so most daughterboards don't even have the extra
connector, meaning you can't upgrade a second-hand/used machine with an
onboard SSD unless you can somehow get hold of a daughterboard with the
extra connector, and even then you must go through all the above and
more just to fit an onboard SSD. By comparison, with a Precision M6700,
you simply take off the bottom cover - just two screws. It rather
reminds me of stories of having to take the engine out of a mini to
change the battery, or the Citroen GSA (IMS) where everything was so
cluttered under the bonnet that to do any significant work in there was
an absolute bloody nightmare.

* A Dell irritation, what effectively are Service Manuals are frequently
called Owner's Manuals.

Post by VanguardLH

Post by Java Jive
:-( Also, the Inspiron's speakers are knackered.

Whatever that means. If you decide to repair (instead of trash), you
could inspect the speakers when dismantling.

It means they distort the sound verging on unacceptably.

Post by VanguardLH
http://youtu.be/cwr_rg7f02s
That one shows replacing the speakers. Looks like you have to buy a
custom speaker module from Dell.

Not worth it, second-hand maybe, but then you don't know whether the
replacements would be any better.

[Paul]

Post by Char Jackson

Post by Java Jive
This is a deliberate cross-post concerning a presumed hardware problem.
This happened on turning on this laptop this morning, it's a Dell
   www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg
The pattern is rather unusual.  In the past, nearly always I've seen
video faults that concern one of the primary colours ...
   Dead red = cyan (turquoise) cast
   Dead green = magenta (purple) cast
   Dead blue = yellow cast
... but this patterning is rather different.
And it's not constant, but changes over time, for example it changed
somewhat as I moved the mouse, and in fact for a while now it's gone
altogether.  I suspect that temperature may have played a part in its
appearance immediately on switching on and its subsequent disappearance
as the PC warmed up, a loose connection possibly.
Or the screen or the video card is dying.
Does anyone recognise the rather unusual patterning and can be more
specific in their diagnosis?

I have the same model of laptop, in continuous 24x7 service since early 2012. No
video issues so far.
What would you think about temporarily connecting a second display to the
laptop*, with the idea being that it may help to determine whether you have a
display panel issue or a GPU issue. I would think that a panel issue is a bit
more likely.
*There should be an HDMI connector and a VGA connector on the left side. I use
VGA to drive a second display, but I've used HDMI in the past and it also works
fine.

Unfortunately I have no alternative display.  My external monitor caught fire some years ago and I never replaced it.
  -  If I disable the AMD Radeon HD 7730M as Paul suggested, there is no change, the screen still shows the effect.
  -  When the display has been on for a while it seems less likely to show the problem, but when it has been blanked by the screensaver for a while, it's more likely to show the problem immediately after being turned on by moving the mouse or typing.
  -  But the killer diagnosis is this: if I alter the angle of the lid, all hell breaks loose until I stop moving it!
So now I must decide whether I think it's worth trying to source another, probably used, display and attempting to fix it ...
  :-(  Unfortunately, these clam shell laptops are a PITA to take apart and repair.  Usually, changing a laptop display is a relatively quick job, because the lid will be held on by a small number of screws, and usually the display is connected under the keyboard and the WiFi and other possible aerials connect to the card(s) either also under the keyboard or else under an easily removable bottom cover  -  often the trickiest part is simply getting the aerial cables to feed through a small hole or cutout to get them beneath the motherboard  -  all of which means that you can just buy a lid/display as a unit off a used PC that has failed somehow else, and swap it easily with your broken one. However on these buggers you have to remove the palm-rest and the bottom of the case, lots of screws, and lots of other things to disconnect on the way and to forget to reconnect as you re-assemble it  -  that may even be why I now have this problem, because I went through all that to
change the fan 10 months ago, though I rather think it's actually the display screen itself rather than the connector, because the hinges are so tight that every time you open or close the lid it flexes slightly, and given the events of the day, I'm now suspicious that this flexing, over the years I've had the PC (from new), is the root cause of the display giving up.
  :-(  Also, it's quite a limited screen resolution, and, having had to replace already two of the Dell Precision M6300s with their lovely big screens within about 6 months of each other, I now have two Dell Precision M6700s both of which are higher spec than this, and, although they don't have the same height resolution as the 6300s, the better of the two does have a higher screen resolution than this, so I was planning to turn it into my principal PC anyway.
  :-(  Also, the Inspiron's speakers are knackered.
  :-(  Also, it can't fit into a dock as can the 6700/6800/etc series.
So I think I might just let it go.  Can't complain, if it's worth nothing now, it works out that it's cost me £69pa in depreciation, and that seems reasonable to me.

What part of the panel would that pattern come from ?

Did you shoot the picture with a high speed camera ?

Does the pattern stand still, or does it vary continuously (jiggling, dancing) ?
That's not failing I/O snow I'm looking at. There is
a pattern there. You could be showing me a static pattern
or a moving pattern (stopped with a high shutter speed).

It helps to understand where that pattern comes from, for the
next time. Panels have driver chip failures (these are chips
on or near the glass panel), which drive the
LCD matrix, and the orientation of the fault then, is lines
on the screen. Horizontal or vertical lines.

For a nice failure condition, you need silicon that has the
capability of making the pattern. An I/O failure can give you
snow. A lack of HDCP support, might give you encryption-snow.

GPUs can make some really neat failures. One GPU failure,
it drew filled circles on the screen, not all of the same
size. It's hard to imagine how or why such a thing would
happen, but only the GPU has enough compute to do stuff
like that.

An external monitor to test with, can cost $100 on January 15th,
but the back-to-school marketing interval starts now, so the
prices will be jacked to take advantage right now. I try to
check the adverts around Jan.15, to acquire an emergency monitor
for later. And then you have to get the right connectors on it,
to make it a good match for your computer room.

You can take a screenshot, with a print-screen or with a snippingtool,
and see if the pattern is evident. It should not be, because
the fault is downstream of that point. If you can see a problem
at that point, it could be a system memory issue (and othe

[Java Jive]

Post by Paul

Post by Char Jackson

Post by Java Jive
This is a deliberate cross-post concerning a presumed hardware problem.
This happened on turning on this laptop this morning, it's a Dell
   www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Video_Fault.jpg
The pattern is rather unusual.  In the past, nearly always I've seen
video faults that concern one of the primary colours ...
   Dead red = cyan (turquoise) cast
   Dead green = magenta (purple) cast
   Dead blue = yellow cast
... but this patterning is rather different.
And it's not constant, but changes over time, for example it changed
somewhat as I moved the mouse, and in fact for a while now it's gone
altogether.  I suspect that temperature may have played a part in its
appearance immediately on switching on and its subsequent disappearance
as the PC warmed up, a loose connection possibly.
Or the screen or the video card is dying.
Does anyone recognise the rather unusual patterning and can be more
specific in their diagnosis?

I have the same model of laptop, in continuous 24x7 service since early 2012. No
video issues so far.
What would you think about temporarily connecting a second display to the
laptop*, with the idea being that it may help to determine whether you have a
display panel issue or a GPU issue. I would think that a panel issue is a bit
more likely.
*There should be an HDMI connector and a VGA connector on the left side. I use
VGA to drive a second display, but I've used HDMI in the past and it also works
fine.

Unfortunately I have no alternative display.  My external monitor caught fire some years ago and I never replaced it.
  -  If I disable the AMD Radeon HD 7730M as Paul suggested, there is no change, the screen still shows the effect.
  -  When the display has been on for a while it seems less likely to show the problem, but when it has been blanked by the screensaver for a while, it's more likely to show the problem immediately after being turned on by moving the mouse or typing.
  -  But the killer diagnosis is this: if I alter the angle of the lid, all hell breaks loose until I stop moving it!
So now I must decide whether I think it's worth trying to source another, probably used, display and attempting to fix it ...
  :-(  Unfortunately, these clam shell laptops are a PITA to take apart and repair.  Usually, changing a laptop display is a relatively quick job, because the lid will be held on by a small number of screws, and usually the display is connected under the keyboard and the WiFi and other possible aerials connect to the card(s) either also under the keyboard or else under an easily removable bottom cover  -  often the trickiest part is simply getting the aerial cables to feed through a small hole or cutout to get them beneath the motherboard  -  all of which means that you can just buy a lid/display as a unit off a used PC that has failed somehow else, and swap it easily with your broken one. However on these buggers you have to remove the palm-rest and the bottom of the case, lots of screws, and lots of other things to disconnect on the way and to forget to reconnect as you re-assemble it  -  that may even be why I now have this problem, because I went through all that to
change the fan 10 months ago, though I rather think it's actually the display screen itself rather than the connector, because the hinges are so tight that every time you open or close the lid it flexes slightly, and given the events of the day, I'm now suspicious that this flexing, over the years I've had the PC (from new), is the root cause of the display giving up.
  :-(  Also, it's quite a limited screen resolution, and, having had to replace already two of the Dell Precision M6300s with their lovely big screens within about 6 months of each other, I now have two Dell Precision M6700s both of which are higher spec than this, and, although they don't have the same height resolution as the 6300s, the better of the two does have a higher screen resolution than this, so I was planning to turn it into my principal PC anyway.
  :-(  Also, the Inspiron's speakers are knackered.
  :-(  Also, it can't fit into a dock as can the 6700/6800/etc series.
So I think I might just let it go.  Can't complain, if it's worth nothing now, it works out that it's cost me £69pa in depreciation, and that seems reasonable to me.

What part of the panel would that pattern come from ?

Dunno.

Post by Paul
Did you shoot the picture with a high speed camera ?

A Pixel 8a

Post by Paul
Does the pattern stand still, or does it vary continuously (jiggling, dancing) ?

Depends, mostly it's fairly static, but it has varied when I move the
mouse, and it varies enormously when I move the lid, and sometimes I can
make temporarily disappear thereby, only soon to return. It comes and
goes when the lid is stationery, but is more prevalent when the display
first comes on after being blanked for a while. The complexity of the
screenshot I shared is partly due to the complexity of the login
background picture. After logging in, things look simpler and more
regular. Here is a photo of the screen while WinDiff is checking for
differences between drive contents of the Inspiron and this M6700 which
I have now moved over to using instead, so that if I ditch the former I
can be sure of not losing any data (the differences you can see there
are either spuriously caused by accented characters in the filename or
else genuinely don't matter):

www.macfh.co.uk/Temp/20240801_Dell_Inspiron_15RSE_7520_Video_Fault.jpg

Note particularly:

- The 'comparing ...' bar should not contain any green at all;

- The regular repeated patterns in the title bar, of which the least
and most intensively green are fairly stable, but those midway between
sometime jiggle.

Post by Paul
[snip]
You can take a screenshot, with a print-screen or with a snippingtool,
and see if the pattern is evident. It should not be, because
the fault is downstream of that point. If you can see a problem
at that point, it could be a system memory issue (and other
stuff would have crashed).

I've already thought of that, a screenshot taken with <PrintScreen> or
<Alt-PrintScreen> when viewed on another PC is free of the fault.

--

Fake news kills!

I may be contacted via the contact address given on

[Folderol]

On Thu, 1 Aug 2024 14:30:26 +0100

Post by Java Jive
I've already thought of that, a screenshot taken with <PrintScreen> or
<Alt-PrintScreen> when viewed on another PC is free of the fault.

The it's *definitely* either screen and/or screen connecting cable

[Paul]

Post by Folderol
On Thu, 1 Aug 2024 14:30:26 +0100

Post by Java Jive
I've already thought of that, a screenshot taken with <PrintScreen> or
<Alt-PrintScreen> when viewed on another PC is free of the fault.

The it's *definitely* either screen and/or screen connecting cable

This could be the screen connecting cable.

https://en.wikipedia.org/wiki/Transition-minimized_differential_signaling

It claims the I/O is DC coupled (unlike PCI express, which is capacitively coupled).
If a wire breaks, perhaps the output is a fixed set of symbols for that gun.
Like most low amplitude diff signalling on a computer, the termination is 100 ohms
(across each pair).

The I/O needs four pairs (RGB Clock), three grounds for crosstalk isolation,
then +12V and GND for power for the panel. If the data rate was 1650Mb/sec,
the clock would be 165MHz. A PLL synthesizes a sampling clock (1650MHz).

The panel needs to derive a signal called DE (Display Enable), which is a
logic 1 for visible parts of the screen and logic 0 for the rest. If the
panel cannot make DE, then the image should be a black screen. the 8B10B code
provides opportunities (JK) for sending synchronization primitives. In its
way, DE is the embodiment of HSYNC/VSYNC.

Paul

[Java Jive]

Post by Paul

Post by Folderol
On Thu, 1 Aug 2024 14:30:26 +0100

Post by Java Jive
I've already thought of that, a screenshot taken with <PrintScreen> or
<Alt-PrintScreen> when viewed on another PC is free of the fault.

The it's *definitely* either screen and/or screen connecting cable

This could be the screen connecting cable.

I think it was (note the past tense) ...

It occurred to me that I still have a spare unattached M6300 screen, so,
assuming that they would have the same connectors at each end and
therefore I could test the screen and cable separately, I started to
dismantle the lid while it was still on the base. This was unwise,
because too late I discovered that the lid is constructed in such a way
as that it can only be completely dismantled when detached from the
base, because there is a screw hidden under each hinge cover which is
only accessible after the hinge cover has been removed, and this can
only be done with the lid removed from the base. As a consequence, I
broke the plastic attachment point of one of them through not realising
this, so now I need a new lid, but have already found and ordered one
that looks right for less than a tenner on eBay, which I was happy to do
because that seems cheap by comparison with needing a new LCD which was
what I expected to prove, but instead I ended up proving the opposite.

When finally I got to it, the screen end of the connection cable is
entirely different from the M6300 one, so I was forced after all to
dismantle the main PC which I had been trying to avoid, only to find
that the motherboard end was different as well. However, when instead
of my planned test I just attached the Inspiron screen floating free on
the desk back to the motherboard and switched on, there was no hint of
green, no problem in fact, and so it remained for several hours, even
when I tried moving the cable and the screen about on the desk.

As I did not dare to try to disconnect the screen end of the cable,
because it looked complicated and was covered with "Don't touch!"
stickers, but I did remove and replace the motherboard end, my best
guess now is that the motherboard end of the cable, through a process of
heating up and cooling down, had walked itself partly out of its
connecting socket. Supposedly this should have been prevented by it
being held in place by sticky tape, but maybe that allows some creep
when it warms up.

However that may be, hopefully when the replacement plastic arrives I'll
be able to restore the laptop to a fully working state.

Thanks to all who've given help and advice along the way.

[NY]

Post by Java Jive
As I did not dare to try to disconnect the screen end of the cable,
because it looked complicated and was covered with "Don't touch!"
stickers, but I did remove and replace the motherboard end, my best
guess now is that the motherboard end of the cable, through a process of
heating up and cooling down, had walked itself partly out of its
connecting socket.  Supposedly this should have been prevented by it
being held in place by sticky tape, but maybe that allows some creep
when it warms up.
However that may be, hopefully when the replacement plastic arrives I'll
be able to restore the laptop to a fully working state.
Thanks to all who've given help and advice along the way.

Good luck with getting the screen working again. There was a time when
laptops were assembled in a way that made it easy to disassemble them.
They had little access doors, held in place with a single screw, to get
at the RAM DIMMs, the hard drive, and to slide out the CD or DVD drive.
If you did need to remove the whole "lid", it was held on by lots of
very obvious screws on the underside. The battery was held in place by a
couple of slide locks and could be removed and replaced with a new one
in a few seconds. You didn't have to use a spudger to release plastic
spring-clips, or have to remove the keyboard to get at screws hidden
underneath.

But nowadays everything is fitted for life, and there is no expectation
that the owner or a repair technician can swap out defective parts as
they could with a desktop PC. When (not if) my present laptop battery
stops holding its charge, goodness knows how I will get to the battery
to replace it. The underside of the laptop only has two screws at one
corner, so unless *all* the screws are hidden under the rubber strips
that constitute the feet, then everything is held in place by clips or
by screws that require access from the keyboard side.

I do PC repairs for a living but I won't touch laptops if it's a
hardware problem that requires the back to be removed, because of fear
that I will break some fragile clip. Let some other poor sod attempt
that work!

In the "olden days", if a laptop failed to boot, a last resort was to
remove the HDD, connect it as a slave drive via a USB-to-SATA or
USB-to-IDE caddy interface, and read the user files in
c:\users\<username> once Windows had gone through the lengthy "take
ownership" process - assuming the user hadn't encrypted the drive. But
if you can't get at the HDD, you're stuffed.


I did once *try* to replace the backlight on one of my laptops. The
screen worked perfectly but the backlight stopped working. I tried
replacing the control circuit, which was comparatively easy to get to,
but that didn't fix the problem so I had to remove the light itself - a
narrow tube that was taped to the end of the glass of the screen without
any location lugs that forced it to be in the correct alignment. I got
it to work perfectly but try as I might I couldn't get the tube aligned
sufficiently accurately to give vaguely even illumination across the
width of the screen. I ended up using that laptop as a desktop - with a
duff screen but always connected to an external monitor.

[Java Jive]

Post by NY

Post by Java Jive
As I did not dare to try to disconnect the screen end of the cable,
because it looked complicated and was covered with "Don't touch!"
stickers, but I did remove and replace the motherboard end, my best
guess now is that the motherboard end of the cable, through a process
of heating up and cooling down, had walked itself partly out of its
connecting socket.  Supposedly this should have been prevented by it
being held in place by sticky tape, but maybe that allows some creep
when it warms up.
However that may be, hopefully when the replacement plastic arrives
I'll be able to restore the laptop to a fully working state.

Arrived today, laptop now fixed, all seemingly well, at least for the
moment I have 'feature'-free display.

As for what follows, yes, I agree completely.

Post by NY
Good luck with getting the screen working again. There was a time when
laptops were assembled in a way that made it easy to disassemble them.
They had little access doors, held in place with a single screw, to get
at the RAM DIMMs, the hard drive, and to slide out the CD or DVD drive.
If you did need to remove the whole "lid", it was held on by lots of
very obvious screws on the underside. The battery was held in place by a
couple of slide locks and could be removed and replaced with a new one
in a few seconds. You didn't have to use a spudger to release plastic
spring-clips, or have to remove the keyboard to get at screws hidden
underneath.
But nowadays everything is fitted for life, and there is no expectation
that the owner or a repair technician can swap out defective parts as
they could with a desktop PC. When (not if) my present laptop battery
stops holding its charge, goodness knows how I will get to the battery
to replace it. The underside of the laptop only has two screws at one
corner, so unless *all* the screws are hidden under the rubber strips
that constitute the feet, then everything is held in place by clips or
by screws that require access from the keyboard side.

The entirety of the bottom plate of the Dell Precision M6700s is held in
by 2 screws + a raft of metal tongues. To remove it, you take out the
battery, undo the two screws, and then slide the cover about 2-3 mms
forward or backwards (I can't remember which, and they're both running
just now, so I don't want to disturb them) which frees the tongues and
and the entire bottom can be just lifted away, revealing 2 of the 4 RAM
slots, the other 2 are under the keyboard, the fans, the card slots, and
the HD mountings - a *HUGE* improvement on both this Inspiron and the
older Precision M6300s.

Both the Inspiron and the Precision M6300s have reasonably accessible
RAM and HDs, and the M6300s also have easily accessible card slots, but
there ends convenience of upgrade or repair for either.

With the Inspiron, you have to take the palm-rest off to get at the
card-slots, or rather, mostly, the single slot, because in that model
Dell were so mean that they didn't actually include the second-slot
unless you specifically ordered a model with a card-style SSD - on the
other models, the vast majority, the circuitry seems all to be there for
the second slot, but they decided to save a few fractions of a cent by
not having the second slot soldered into its place on the daughterboard.
So, even if you were willing and able to go to the trouble of a
near-complete dismantling of the PC to upgrade it with a card SSD, you
couldn't, unless you were also willing to try your hand at soldering the
second slot into place, or else were lucky enough to be able to find a
replacement daughterboard with the 2nd slot, which seem to be as rare as
hens' teeth.

The Precision M6300's fans tend to get very noisy when they get old, as
do the Inspiron's single fan, though for me at least its noise was
rather more bearable than the other, but, despite the fact that fans are
moving parts and therefore a need to change them is absolutely
predictable, with both a near-complete dismantling of the laptop is
required to do so.

The Inspiron has been particularly bad in this respect, the laptop
equivalent of the Citroen GSA models which cost a fortune in garage fees
because everything was so densely packed under the bonnet that you
couldn't do anything without removing something else first. Hopefully
never again will I have ever to work on either!

Post by NY
I do PC repairs for a living but I won't touch laptops if it's a
hardware problem that requires the back to be removed, because of fear
that I will break some fragile clip. Let some other poor sod attempt
that work!
In the "olden days", if a laptop failed to boot, a last resort was to
remove the HDD, connect it as a slave drive via a USB-to-SATA or
USB-to-IDE caddy interface, and read the user files in
c:\users\<username> once Windows had gone through the lengthy "take
ownership" process - assuming the user hadn't encrypted the drive. But
if you can't get at the HDD, you're stuffed.

Yes, and, one of the stupidest ever defaults of most recent versions of
Windows, if you get a bluescreen it's been and gone before you can
possibly read it as the laptop goes into an endless cycle of rebooting
- the only way you can read the details on the screen is to video it
with a mobile phone and try, probably several times before you are
lucky, to freeze the playback at exactly the right moment to be able to
read it. That most stupid of defaults is always one of the first things
I change on any new installation of Windows.

[Paul]

Yes, and, one of the stupidest ever defaults of most recent versions of Windows, if you get a bluescreen it's been and gone before you can possibly read it as the laptop goes into an endless cycle of rebooting -  the only way you can read the details on the screen is to video it with a mobile phone and try, probably several times before you are lucky, to freeze the playback at exactly the right moment to be able to read it.  That most stupid of defaults is always one of the first things I change on any new installation of Windows.

There is a setting for that. Disable "automatic restart" or so.
This causes the blue screen to stand still. Then you can get out
your magnifying glass, and read that annoying five point font
the idiots selected for the code.

That could be in sysdm.cpl somewhere.

[Picture]

Loading Image...

Dump files can be read with dumpchk.exe , one of the early
tools from MSFT to read a minidump. Windbg (available
separately as a Visual Studio sub-feature) can read dumps
or full memory dumps, in a similar manner to dumpchk. !analyze
Windbg has a comment, right in the interface, what to use...

Third party tools (BlueScreenViewer) also exist, but
occasionally they don't know where the .dmp files are.

After you have set up your crash response. you can test it.

https://learn.microsoft.com/en-us/sysinternals/downloads/notmyfault

The one on the display there, that ought to do it. Close
all your Notepads, MSWDs, Firefox, make sure anything of
value is put away. Right after a full backup, might be
a good time for a test. The "High IRQL fault" should
blow a similarly named Blue Screen for you. The Reliability
Monitor will then have an entry for NotMyFault.exe as the
thing that dropped the system or created a .dmp. Russinovich+Co
wrote that for us.

If you're bored, you can have a lot of fun making minidmps
and testing viewers and such.

Note that, if you encourage the system to dump all memory,
the writing of the memory to some place on C: , is
excruciatingly slow. You will have regrets about
some of those options. But I don't see the "mini dump"
option in the pictured one, so I guess the system
knows when it's supposed to make a small one.
If you have hiberfile turned off, there's no place to store a big dump.

powercfg /h off # Can't hibernate, also "can't take a dump"
# Minidmp .dmp files could be 100KB.

I am trying to remember why I do *NOT* have
this option selected (BSOD stand still). The automatic restart
might be "cleaner". But when you don't have hints, and the
problem is re-producible, you might use this. If the system can
produce a BSOD, maybe it can manage to log it. Eventvwr.msc might
contain the code. Or reliability monitor.

For the problems I was having with the Zen3 processor, the system just halted,
and the event viewer only reported a dirty shutdown had occurred (no log).
It felt like the BIOS was halting it (on an SMI/SMM). There
was no MCE logged (Machine Check Error), so whatever the problem
(Vcore?), it was not something tied to MCE. I'm not used to weirdness
like that (the lack of documentation does not help). There is always
something on computers, you've never seen before. The processor (so far)
runs fine on a different mobo. Great, I guess.

You would be surprised on computers, how many features and
codes are not documented. The mobo makers are sloppy, because
they're designing 30 of the stupid things in parallel every year,
and there is no time for frippery. That's how they can have BIOS
manuals today, that apply to a whole bunch of boards, rather than
just one board.

Paul

[NY]

Post by Paul

Yes, and, one of the stupidest ever defaults of most recent versions of Windows, if you get a bluescreen it's been and gone before you can possibly read it as the laptop goes into an endless cycle of rebooting -  the only way you can read the details on the screen is to video it with a mobile phone and try, probably several times before you are lucky, to freeze the playback at exactly the right moment to be able to read it.  That most stupid of defaults is always one of the first things I change on any new installation of Windows.

There is a setting for that. Disable "automatic restart" or so.
This causes the blue screen to stand still. Then you can get out
your magnifying glass, and read that annoying five point font
the idiots selected for the code.
That could be in sysdm.cpl somewhere.
[Picture]
https://i.postimg.cc/sghZL2h2/automatically-restart.gif

For Windows 10, it's a slightly different route to the same option:

Loading Image...

It was already turned off - and I don't remember doing it, so evidently
Win 10's default it more sensible than Win 11's.

[Java Jive]

Post by Java Jive

Post by Java Jive
However that may be, hopefully when the replacement plastic arrives
I'll be able to restore the laptop to a fully working state.

Arrived today, laptop now fixed, all seemingly well, at least for the
moment I have 'feature'-free display.

Spoke too soon, there is now some sort of smudge of darker pixels in the
centre of the screen that won't wipe off, and I'm not sure what I did
wrong to cause it (it's much more obvious in real life than this photo
suggests):

www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Smudge.jpg

[Paul]

Post by Java Jive

However that may be, hopefully when the replacement plastic arrives I'll be able to restore the laptop to a fully working state.

Arrived today, laptop now fixed, all seemingly well, at least for the moment I have 'feature'-free display.

www.macfh.co.uk/Temp/20240731_Dell_Inspiron_15RSE_7520_Smudge.jpg

You must have handled something optical. Might not be CCFL related,
but maybe some gadget that spreads the light.

Paul