S-XPS 1645 RGB screen flicker issue

Does your screen flicker on AC:
Does your screen flicker on Battery:
Laptop Model:
BIOS version:
Screen type:
Screen refresh rate:
Power supply model:
Local power service; 50hz/60hz, 120v/220v:
Brightness levels that make it more visible:

You are correct. Here is that thread.

At this point we are looking for common factors. Post up any other useful information you can think of.

Does anyone know the Hz of the backlights?

Does this flicker still happen on an external monitor?

Human vision factors:
Most people can see flicker at about 80 hz. This is most noticeable in bright light and in the peripheral vision areas. Most people adjust to the flicker rate of their local power so that they no longer notice the flicker.

Most people can see an animation as continuous movement at about 20 Hz. The brain tends to understand that it is seeing an animation and assembles it as movement. On things that are not moving, the flicker is more noticeable as your brain has nothing it can assemble the flicker into.

Some people have said that they can see the flicker while other people around them can't. This could be because some people are less sensitive to noticing flicker. This could also be because the other person is looking at the screen from farther away (say, over the shoulder of the owner) and the screen is centered in their vision, not in the peripheral vision areas. If you are one of these people please let us know it your test persons have actually sat directly in front of the laptop, just like you normally would be when you see the flicker.

I suspect the flicker is actually due to the Hz of the backlights, not the actual refresh rate of the screen.

Of course, I could be wrong.

 

I no longer own my 1645 so I can't answer all of those questions but I can confirm that I had a 90w adapter on 120v @ 60Hz.

The flicker on the RGBLED was terrible. On all but the highest setting (which is unusably bright), it would flicker intermitantly. Very distracting and unpredictable (it did not seem to coincide with HD access, high power activities like gaming or heavy CPU utilization, etc.).

It was one of many issues I had that ended up being solved with a return.

 

(1) No flickering

(2) RGBLED

(3) 120V @ 60Hz

(4) 130W adapter

(5) I used a full-screen white background and stepped through each brightness level from lowest to highest, looking for flickering. None was observed.

I really have to consider myself very lucky. Other than the throttling issue, I have not experienced a single problem with my machine. No misaligned hinges or edges, no mysterious crashes or lockups, no overheating, etc. Judging from these forums, I seem to be one of the few without serious issues.

 

I have the RGB screen with a 90w and 130w adapter on 120V 60Hz power.

The screen flickers maybe every couple of minutes on lower brightness settings. I'd say between 60%-100% brightness I don't notice any. It's not very distracting, but it is definitely noticeable. Again, it only happens every few minutes, so I guess I'm fortunate in that respect.

I haven't noticed any difference between the 90w and 130w adapters. I keep the 130w plugged in all the time in my room, and keep the 90w in my backpack (I take my laptop with me every day).

Also haven't noticed any difference whether it's on battery power.

 

I had one of the flickering RGB LED screens on the xps 1645

220v 50Hz

90w adapter

This thread should include all Dell models with RGB LED screens, not just xps 16, to help determine problem.

After this and the throttling problem Dell has lost all credibility for me now.

 

Laptop Model: SXPS 1645

Does your screen flicker? Yes.

Please post your screen type. RGBLED 1080p

Please post your local power service; 50hz/60hz, 120v/220v. That way we can see if that's an issue or if it's not. 120v @ 60hz

Please post your power supply type, as well. 90w and 150w

Also, post up any other useful information you can think of. It's occasional, usually happens for no apparent reason. Will happen at any brightness level.

 

Model: SXPS 1645

Does your screen flicker? Definitely Yes

Please post your screen type. RGBLED 1080p

Please post your local power service; 50hz, 220v.

Please post your power supply type, as well. 90W

From my experience with this problem so far I do not think the problem is within the local power service. There is no difference whether the laptop is working on battery or not.

I have also tried all possible GPU drivers. Yet no difference. Tried with the ATI Power Play disabled - no luck. I thought there might be some kind of sensors not working well - again this is not the problem. This laptop has no sensors.

Yet not proven, but I think that the problem might be related to a device working near the screen. Something in the environment - like an UPS. This is so, because when I am at home I hardly notice any flickers. But when I am in the office it flickers almost every minute or 30 seconds. Quite annoying. The laptop is plugged behind an UPS.

Do you think that this could be the problem?

Nikolay

 

I think that it will be also helpful if you guys share your BIOS version. Mine is A03

Nikolay

 

I've had four screens in total (three replacements) and two flickered and two didn't (only below ~ 50% brightness).

240V 50Hz 90W.

 

New BIOS A06 does not fix this problem

 

Do you think the problem might be because of the heat coming from the left side of the laptop. This side if the display is quite warmer.

Nikolay

 

I too have wondered of the heat is part of the problem.

I have updated the first post in this thread.

 

Good point. It could be very well.

 

I am assuming this, because I noticed something strange (or may be this is a normal behavior). So, I would be grateful if you can check it too and share your opinion.

Set your desktop background to black and brightness to 100%. See at the left bottom side of your screen. On mine I can see a lot of back light coming upfront. Black color is almost grayed. Hope this makes sense.

Nikolay

 

Do you know if they replaced the backlight each time?

 

Some guys say that after mobo and display replacement the issue is gone. Perhaps this is a hardware problem.

Nikolay

 

I have had my screen replaced twice and the mobo once. My screen still flickers. They are sending me a new laptop which I will get tomorrow. I'll let you all know how I get on.

 

Keep us posted, please. I am considering to replace mines mobo and display as well.

Nikolay

 

Got my new 1645 today, sadly it still flickers. I am now convinced it's a problem with the design of the screen. I will say that those you are not having any problems probably still have a flickering screen but they just don't notice it. I've with a few people and some of them notice the flicker straight away and some can't see it at all. Either way it does still flicker.

I now don't know what to do. Send it back or keep it and put up with it. When I think about the throttling issue I just can't see the sense in keeping it although I really want to!

They upgraded my HDD to a 256ssd free because of the trouble I've been having so if I send it back i'll be sending that back too!

The Envy 15 does not come with USB 3.0 or HD screen in UK so i'm not going for that and I don't want anything bigger or heavier than the XPS 16.

Anyone got any advice?

 

I would suggest you look at one that has the lower end screen and see if it has the same flicker.

My suspicion is that the backlight is the problem and even then, not everyone can see the flicker on units that do flicker. I am betting the lower end screen uses a different backlight.

 

Yeah, i think i will have to do that. I did try to do that before they sent me the replacement but he told me I would not get a refund for the RGB screen I already paid for. I was not accepting that which is why i got this screen again!

 

Hey guys. Today I noticed something REALLY strange. As I said before I see this problem only when I am at work in the office. At home I hardly notice any flickers, even though it happens sometimes.

So, in my office I have a window behind me and every morning there is direct ambient light landing on my screen. Today I noticed that the sun light is landing directly on the right side of the screen and the screen dimmed. The brightness dropped down even more than the default minimum (as I keep it at minimum). I put my hand on the right side of the screen and the brightness was restored to default. Removed my hand - again screen dimmed.

After few minutes the sun moved a bit and the light was no longer landing on my screen and this behavior disappeared.

I really hope this makes any sense . Perhaps this is the source of the flickers, because they are most noticeable when there is huge amount of ambient light in the room.

Nikolay

 

Does your screen flicker on AC: Yes
Does your screen flicker on Battery: Did not test
Laptop Model: Dell Studio XPS 1645
BIOS version: A06
Screen type: RGBLED 1080p
Screen refresh rate: 60 Hz
Power supply model: FA90PE1-00
Local power service; 50hz/60hz, 120v/220v: 50Hz/220V
Brightness levels that make it more visible: Lower settings mostly, but all settings are affected.

 

I have had no issues with flickering at all using either my 120V 60Hz adapter or battery. But I have had the screen go all red or blue on me on rare occations usually when the battery is low and I plug in the adapter.

 

Does your screen flicker on AC: Yes
Does your screen flicker on Battery: Don't know, hardly ever work on battery, but will check soon.
Laptop Model: Studio XPS 1645
BIOS version: A03, X29, A05, A06, they all do it.
Screen type: 1920x1080 RGBLED
Screen refresh rate: default
Power supply model: 90W
Local power service; 50hz 220v
Brightness levels that make it more visible: Doesn't make much difference, only at the brightest setting I haven't seen it more than once. But that is too bright for my work.

 

Have you tried the display self test when powering up your laptop. Try it and let me know your result please. To do it you have to completely turn of the lappy. Then hold down the D button on your keyboard and then press the power button.

The display test must start. Mine - failed. So I requested display replacement. The guys said that the issue might be due to loose connection or something.

I will update you once the screen is replaced.

Nikolay

 

My 1640 RGBLED Screen Flickered, My new 1645 Screen does not. (just way too blue)

 

I just had to reboot my system, so I figured might as well try the display test.

I pressed and held the D key, and pressed the power button next. I heard some beeps, but nothing showed on the screen. The system didn't eve continue to boot after that. Had to power down and restart.

What happened in your case?

 

Oops wrong thread.

 

Same happened here, so I am awaiting a visit from Dell. The guy on the phone said that I should had seen red, blue and green colors, but the test had failed. So I would advice you to contact Dell as well.

Nikolay

 

Does your screen flicker on AC: Yes
Does your screen flicker on Battery: Yes
Laptop Model: Studio XPS 1645
BIOS version: A03, A06 - both have the issue
Screen type: 1920x1080p RGBLED
Screen refresh rate: 60Hz
Power supply model: 90W
Local power service: Uh... not sure on this one. Whatever the standard US 3-pronged power outlet is. (240V or something?)
Brightness levels that make it more visible: Visible on ALL brightness settings. Least visible on max brightness, almost unbearable on lowest brightness.

I'm going to run the self-test right now and post the results...

EDIT: Screen diagnostic passed... Interesting, because IT WAS FLICKERING DURING THE TEST!

 

Display has been replaced. So far not flickers, but I need some more time to test it. Yet the D+Power test fails with the following beeps sequence: 2-3-4-3. According to the Phoenix bios docs this means: Display non-disposable segments.

So, new mobo on its way .

Nikolay

 

Ok so just tried this D+Power: I get the same beeps 2-3-4-3 and it doesn't power-up. The Diagnostics go through fine.

Has anybody got this working showing Red Green and Blue? All I get is a quick (less than half-second) what appears to be 3 separate rows of pixels and then it goes blank with the beeps next. This doesn't look like screens or rows of R G B.

added: yes mine flickers though not too badly, it's there.

 

YES !!! I get the same beep code.
I haven't noticed any flickering but I have had the all blue or red screen a couple of times.

 

I just did the test again and it yielded the same results. Went ahead and reported this to tech support.

 

I think the diagnostics does not work with the RGB screens and no one at Dell has realised this - They have no clue what they are doing and because the test fails they just start replacing screens and motherboards. I have tried on 2 screens on my 1st 1645 and on the replacement 1645 and the diagnostics fails on all of them.

So unless they are all faulty screens (which could be possible as they all bloody flicker) then Dell just doesnt know the screen is not compatible with this test!

 

That may or may not be true, I wouldn't know. I just reported my problem with the screen (flickering) and mentioned the diagnostic as one of the things I have tried myself. It is for Dell to decide how to interpret the results of this test.

Your point is quite interesting though. Only time will probably tell what's really going on, or it might not.

 

I will try to get the answer to this. Indeed, perhaps the test is not compatible with RGBLED screens.

So far there are not flickers with the new screen, but as I said I need couple of days to monitor it. Wish me luck, guys

Nikolay

 

Keep us posted, still deciding whether to send my replacement back too as my screen still flickers but im trying to ignore it rather than go with the 1080p wled screen!

 

Does your screen flicker on AC:
Does your screen flicker on Battery:
Laptop Model:
BIOS version:
Screen type:rgb
Screen refresh rate:60hz
Power supply model:90w
Local power service; 50hz/60hz, 120v/220v:120v
Brightness levels that make it more visible:1,2
Happen once or twice on battery, have not see it in AC yet

 

Sorry forget the following
AC:no
Does your screen flicker on Battery:yes
laptop model 1645
Bios A03

 

The diagnostics test isn't compatible with the RGBLED screens.

The tech support staff are clueless, but you can use it as a quick an easy method to get a replacement if you have dust under your screen or flickering

 

I'm getting a new screen on monday, and not the low cost one that was mentioned in another thread:

Will let you all know how that works out.

 

I have received the new screen, and so far it doesn't seem to flicker. I will hold of on a permanent verdict for a few more days, but it's looking good.

 

Is there any way of determining what batch of panels yours is from?

I got my first laptop on 12/12/09, went through 2 screens and a motherboard. Then got a completely new system a few weeks ago and they all flicker!

 

sorry.

It looks like mine is a generic panel, as all I can find is the default PnP monitor from Microsoft.

Bummer.

I still use the ship date, as that is what Dell is using when I look at the system configuration screen on dell.com.

 

After doing some reading, and after looking at different manufacturers, it seems that this issue is pretty much affecting everyone; and all when they lower the brightness of their displays.

"Through some internet searches and participation at other forums, I discovered that LED displays uses pulse width modulation (PWM) to dim the display. PWM in effect, flickers the screen on and off at variable rates to create the illusion of a dimmer display."

see this thread....

"Re: screen flicker resolved?
Posted: Jun 21, 2009 7:45 AM in response to: Jeff Storm
Click to reply to this topic Reply email Email

Hopefully I can shed some light (no pun intended) on the backlight flickering issue at low brightness. I have designed fpga controllers for LCD panels, and the issue is a combination hardware/firmware issue.

I purchased a uMBP in October and never saw any backlight flickering at low brightness with either GPU. I just received a newer uMBP and it shows the backlight flicker problem only on the 9400. It was immediately obvious what the problem is. The LCD panel has an underlying repetition rate as does the LED backlight controller since it uses PWM techniques to dim the lamps. Apple did not provide enough filtering on the LED PWM controller so the LED's are actually slightly flickering on their own at the rate of their PWM controller. This is not a problem on it's own as the PWM frequency is always high enough that the human eye can not perceive it. The problem is when this frequency or it's harmonics are close a frequency of the LCD, patterns will be created in the light intensity called beat patterns. Since these beat patterns are dependent on the absolute frequency of the LCD and LED PWM, and since each GPU and the LED PWM are sourced from different clocks, the issue will be different for every motherboard, and will vary with such things as voltage and temperature.

I verified my suspicions by slightly shifting the operating frequency of the LCD (not something anyone can do) and the problem went completely away. As I continued to change the frequency the problem would reoccur and subside as the two fundamental frequencies would beat against each other.

The solution would have been to provide better filtering of the PWM supply, but this is a typical trade off that even I would have made when designing a PWM dimming circuit. Also, typical white LED's have a fairly slow response time, so this was probably relied upon for some of the filtering. The other solution is to just shift the frequency of the LCD or LED PWM so that they don't beat. The problem here is again with the absolute frequency (over time, temp and voltage) on each motherboard.

So the bottom line is an LCD replacement will not affect this issue at all (although it may address some of the other issued raised in this thread), and a motherboard replacement is a hit or miss proposition at best, (unless Apple has made a hardware changed, but based on my new uMBP, they haven't) and even if it does appear to fix it at first, it may return later. My guess is (and this is only a guess) a firmware change could be made to shift the clocks to alleviate this problem. This is something I have done to my firmware designs, but is not always possible for other engineering reasons. Certainly the LCD clock rate can be shifted easily, but what complicates the solution is it needs to be universal across all notebooks and that can be a difficult thing to achieve.

So can anyone confirm that they have spoken to someone at Apple that has confirmed they know of the issue and are actively seeking a solution? Without this confirmation, I don't intend to send my MBP back as it can be a futile exercise as pointed out by others in this thread."

http://forums.macrumors.com/archive/index.php/t-731162.html

Maybe Bill or Todd can comment. When I am lowering the brightness of my display, is it actually lowering the brightness or a play on power. If it is a play on power, than is this something that can be addressed via another BIOS update?

Thoughts?

 

This is really helpful information. I replaced my screen already and no longer notice the flicker. I am not sure, may the issue will start to recur as stated above.

But I do not need to be an engineer to say, that there is something wrong with this screen. This is based on all the complaints so far and on a new one on my side.

Now with the new screen, that does not flicker, there is a problem with colors. I can see 2 huge light pink areas when the background is white. I wondered whether this is due to calibration, but it is not else the pink should have been all over the screen. But it is only in two regions of the screen. Hope this makes sense.

Nikolay

 

Seems like everyone is chasing their tails on this problem. My M4400 has the same issue as the XPS16. Replacing the screen, may or may not resolve the problem. Even if it does, you may have issues with coloring, or dust.

It only appears to flicker when the screen brightness is in the middle; not at 100%.