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Compatible displays for T520

Posted: Sat Apr 21, 2012 9:45 am
by kona
Hello all,

My T520 has a HD+ (1600x900) display that I am not entirely happy with as the colours are a quite washed out. I found out that it is possible to replace it with a FHD display, part number AUO B156HW01 v.4, which should have better colours. While I was searching for a place that sells this panel, I also found out that there is a glossy display, part B156HW01 v.7. Now this interests me a lot, as I have used a MacBook Pro in the past and I loved the display. Yes, the reflections can be a problem sometimes, but I think I can live with them.

So does anyone know for sure if it is compatible with the T520?
My understanding is that the criteria that determine compatibility are:
- the location of the connector: bottom left, same as T520
- the resolution: my T520 has a lower resolution, but the graphics card does support FHD and I've seen other people have upgrade to FHD panels
- the backlight: LED same as T520
So it looks like I should be OK?

By the way, I have found the following sellers. The first one looks like it should be genuine. The others are a lot cheaper but I'm a bit sceptical as one mentions "100% compatible" which means it might be an inferior display from another manufacturer, and the other says it is a matte display (I think the v.7 is only glossy)
http://www.ebay.co.uk/itm/230581951870
http://www.ebay.co.uk/itm/140635641917
http://www.ebay.co.uk/itm/190654123654

What do you think? Would you take a chance and get one of the cheaper ones?

Re: Compatible displays for T520

Posted: Sun Apr 22, 2012 2:59 pm
by richk
I prefer the matte screens myself, but I have been researching the upgrade from 1600X900 to FHD (AUO B156HW01 v.4)so I will tell you what I know. The V7 should be the glossy version of the same screen as the V4. I can also tell you that the ones they call matte are glossier than older or other matte screens. I assume this is necessary in order to get the 270 nit brightness figure. The standard for dead pixels is defined in ISO 13406. Most screens made fall into class 13406-2, which allows 2 faults (dead or hot pixels) per million pixels. I believe that Lenovo only tries to buy class 1 (ISO 13406-1) screens (no dead pixels), but specifies that screens will not be replaced in most cases if the screens meet ISO 13406-2 standard, in case a couple fail in early use. Grade A+ screens generally mean no dead pixels, but there is no such official standard, so it means whatever it means. I buy lots of things from Chinese suppliers, so I am not trying to say not to deal with them, but here is how I would guess the process works. The manufacturer (AOU in this case) makes a lot of screens that they guarantee meet 13406-2 standards. Many of those also meet standard 13406-1. If you were buying 1000 screens from AOU, you would get a mixture. I would guess that the ones that don't meet laptop manufacturers' standards get culled out and are sold wholesale to guys who turn around and resell them. My guess is that those are the cheap ones you see, although I have no direct knowledge. I asked some of the sellers about pixel faults and the sellers who responded said they are 13406-2 panels, even though some were called grade A+. I decided to buy one from someone who guaranteed no pixel faults. I hope someone who bought one of the cheaper panels will add something to this.

Re: Compatible displays for T520

Posted: Mon Apr 23, 2012 3:56 pm
by kona
Thanks for the reply richk.

I will give it a shot and try one of those sellers, and then I'll post the results here for future reference.

Re: Compatible displays for T520

Posted: Tue Apr 24, 2012 10:46 am
by FragrantHead
As a matter of interest, you say the colours are washed out on your existing screen, but that screen gets quite good reviews. For example Notebookcheck measured contrast at over 600:1. Washed out colours are normally related to high black levels and poor contrast. I Have a T410s. Contrast is only 100:1. Black levels are high, so it's more like a milky grey when the machine shows a black screen during booting. Is that what you're experiencing?

Of course the FHD screen is meant to be the best, but can you give us some more indication of how bad your HD+ screen is? I wonder do all HD+ screens have 600:1 contrast, as measured by Notebookcheck, or are some of them (yours?) poor with sub 200:1 contrast?

Re: Compatible displays for T520

Posted: Thu Apr 26, 2012 2:04 pm
by kona
Yes black is never completely black, which makes text hard to read, and also the colours lack punch. I have spent quite a bit of time trying to adjust it through all the available utilities (Nvidia, Intel and the Windows one), but I'm not happy with it.

I don't know how to quantify that for you to explain how bad it is, but it's significantly worse than a MacBook Pro. I saw the matte FHD v.4 display has higher contrast and larger colour gamut which might improve things somewhat. Then I found the glossy one (v.7) which sounds even more promising since the MacBook Pro that I'm used to also has a glossy and so hopefully the v.7 will be similar (yes, I'm sure there are even better ones around but I haven't seen them and in this case ignorance is bliss!)

Re: Compatible displays for T520

Posted: Thu Apr 26, 2012 2:44 pm
by FragrantHead
Thanks, the Macbook Pro reference is something I can relate to.