737 NG Home cockpit LCD Panels reference and technical details

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737 NG Home cockpit LCD Panels reference and technical details

#1 Post by jph »

This thread is specifically aimed at selecting and using appropriate LCD Panels in a scale 737 NG home cockpit and offering tech info of such. It will also, when I get the time, cover the technical hardware modification of the Logic (Driver) boards for the LCD Panels so that the backlighting and on/off functions can be centrally controlled from AM via Arduino/Pico. On the 737 NG LCD panels are used in the 6 DUs and the 2 FMC units.

The term LCD PANEL here will refer to the actual LCD 'screen' (Panel) - the part that is usually inside a monitor, TV, Laptop or industrial device. It is usually FAR cheaper to buy the actual LCD panel and driver board than buy a 'monitor' and try to cannibalise it. You will usually end up with a complete mashup of mixed and proprietary parts and an empty wallet if that route is trodden.

The LCD Panels are almost always from specific devices such as high end laptops and notebooks and you don't want to be buying the actual device just for an LCD panel. So again, unless specifically stated ALL references here are to the LCD Panel. We will try to avoid the use of the term 'monitor' as it means a different thing although it may 'sip in' from time to time ;) All control of the panels will be from standardised and readily available HDMI/ eDP driver boards and also TTL/LVDS Driver boards for the 5" 4:3 monitors in the FMCs.
As a rough guide a complete - brand new LCD Panel (1920 x 1080 / IPS / eDP /WLED Backlight) and an HDMI/eDP driver board will usually cost around 150 Euro in the EU for the larger monitor for the dual DUs. Possibly similar in USD, 120 for the same spec but smaller LCD panel for the centre display and the lower EICAS screen using an Ipad 3rd gen 9.7" LCD Panel can cost between 40 an 70 euros complete with driver board. The 5" 4:3 LCD Panels used in the FMCs are around 48 euros complete with driver board. (more on these specific 5" screens in another post) The whole kit for an LCD Panel and Driver board will run from a single 12V supply.

Some notes -
4:3 aspect ratio 10" 'TVs' or 'monitors' are actually 9.7" diagonal in all cases I have seen. The oft' quoted 10" TV units that are recommended on may out of date websites for the lower EICAS are exactly the same size as the ipad 3rd and 4th generation screens and the same aspect ratio 4:3. The LCD Panel / screen from the iPad is the far better choice by a long way. High resolution (very high) and IPS AND eDP so has excellent viewing angles and interfacing is easy.
The 10" 'tv' units are low resolution TN panels which are utterly atrocious in viewing angles. Unless you look directly at the screen at the correct screen angle the image is not clear and will 'contrast shift' dramatically.

A 737 DU is 10" with an AR of 1:1 meaning it is 7" x 7" (180 x 180mm) There simply is NO 7" square monitor available). We could have them made and I don't think think they would be too expensive but the minimum order costs would be quite significant. Having them made with the industry standard interface (eDP) is absolutely necessary so that industry standard driver cards (readily available and cheap) can be used. There simply is NOTHING suitable on the existing market.
So, at the moment a 10" 1:1 ( 7" x 7" square) LCD Panel option suitable for an individual DU is simply NOT an option.

This is why the IPAD LCD Panel (NOTE - NOT the IPad itself - that is important!) (or the crappy 10" tv') is used for the Lower EICAS. It is not 7" wide, it is actually 5.79" x 7.72" (196.6 x 147.4) VISIBLE - this is PLUS the frame of the LCD panel - which fits ok between 2 FMC units each using their own 5" 4:3 monitor. (ZJ050NA units) Anything larger for the lower EICAS hits either the FMC units or extends into the TQ area. Luckily the Lower EICAS shows a narrow display so applying two small matt black strips to the side of the iPAD panel, or, using the iPAD black digitiser screen with its black bezels fills the space nicely. Again, exactly the same screen size as the 10" 'tv' and the 10" tv monitor also needs blanking strips down the sides. The LCD Panel (iPad or other 10" 4:3- (both identical size)) are mounted with the longest side up and down so the TN 'TV' Panel which was already bad is now horrendous as you are never looking straight on and even if the Capt can see it - badly - the FO view will be even worse. Viewing angles on TN panels can be visualised if you have an older laptop. Simply set the screen correctly for best view and then tilt the screen forwards and backwards. You will see contrast wash out one way and 'purple haze' the other. The screen has a polarising filter that is specified at design. A Laptop and almost ALL TN panels are filtered to be viewed directly or from very lightly below. You can also check the extremely limited side to side angles. A 'TV' LC panel rotated 90 degrees, as in the lower EICAS is in it's worst possible orientation.

On the 737NG we are stuck with 4 potential problems due to lack of availability of individual 7" square panels. We need LCD panels for the dual DUs Capt' and FO. We need an LCD Panel for the Centre Display, one for the lower EICAS and 2 for the FMCs.
So, in all scale home cockpits the dual Capt' DU and the Dual FO DU are both fed from the same panel, ie, one panel is used for the 2 DU's per side. It can probably be seen that therefore the minimum 'visual' area of the LCD panel in width must be ((180 x 2) + (210-180)/2) in mm
This formula is for the width of each DU in the pair plus the width of the left side of the right DU frame and the right side of the left DU frame. This presumes the frame is 210mm in width and the visual area is 180mm
In a lot of cases (well most and also different from manufacture to manufacturer of cockpit parts or drawings!) this is slightly different so needs measuring on your actual or proposed units, but, 210 overall width and 178 visual area - PER DU is about right.
This comes out at around 386 to 390mm 'VISUAL' WIDTH of an LCD panel needed to do the job. The Height of the panel will definitely be greater than 210mm so will need to extend below or above the level of the lower edge of the DU. There are often small cut-outs in the MIP support to accommodate this.
Usually an 18.5" LCD Panel out of an old monitor is used but these are basically obsolete now, very low resolution and not available in IPS. Many in use and the ones often recommended on the empty-net are even the old standard TN with CCFL backlights - these are definitely to be avoided even MORE as WLED units are available - such as the Panel form a HP W1972a monitor. They are, unfortunately, all still low resolution TN panels and that is why you can't see the FO panels clearly from the Capt' side and visa versa, or, if you have friends viewing they can basically see bugger all. :?

Let me just clarify monitor sizing - MOST IMPORTANT. Inches are commonly used as the main markets were originally the UK and the US (for TVs) which used imperial measurements. This is NOT the width of the monitor - repeat - the size you see is NOT THE WIDTH OF THE MONITOR SCREEN ! It is a the diagonal measurement of the visible area from the lower left corner to the upper right corner.
Another really important point to note is ASPECT RATIO ! - also a critically important value. This is the ratio of the Width (horizontal) to the Height (Vertical) of the display area. Commonly it is 16:9 earlier units were 4:3

By knowing a monitors ACTUAL size - quoted as diagonal, AND the aspect ratio we can use simple Pythagoras to calculate the Width and Height. This is also where we should change to metric as ALL panel makes use metric for their physical measurements and drawings. (Spread sheet attached - see later)

Many would think, well, why not just look at the datasheet ? - well, the problem is that you would need to know the exact number of the LCD PANEL in use which will not be given in, say, a laptop or monitor manual. Lucky for us there are standard monitor sizes and a very very limited number of LCD PANEL manufacturers so it is easy to find the data and a PANEL of the same size, resolution and display technology - such as IPS with WLED backlighting and Refresh rate is going to be, to all intents and purposes, identical to any other of the same size. For the last 8 or so years an actual standard has been used called eDP based on the DisplayPort standard and protocol which makes it even easier as 95% of monitors produced, certainly in the last 5 years, will be fully interchangeable as even the PANEL connection will be the same. Normally nowadays it is simply a standard eDP 30pin connection. Monitor sellers will boast of their 'incredible crisp colours', their 'fantastic resolution and viewing angles' and mostly it is all bullsh1t as the monitor on the shelf next to it will most likely have the exact same LCD panel from Samsung or Innolux or AUO or LG ......
As an example, LG are used in some PHILIPS, Lenovo, Acer, Apple, HP, DELL, SONY, Toshiba and other designs, but the same design can also use panels from any of the top 5 (if you add BEO) makers of LCD Panels. The Technology in use is basically ALL the same. You will get different terminology but that is usually only due to trademarks that make no difference at all to performance. If you put an AUO replacement panel in an HP Monitor that originally had an LG Panel in it you would absolutely NOT know the difference.

Back to the dual DU panel then. it is often a panel from an 18.5 inch Monitor at 1366x768 resolution monitor that is used - these are obsolete now, and also they are TN :? panels with their associated viewing angle issues. To calculate the ACTUAL size in width and height of the visible area of the LCD Panel in this size of monitor then we can work it out from our 18.5" diagonal and the aspect ratio which is, in this case, 16:9. We can see that the WIDTH is 408.5mm and the height is 229.7mm so is fine for the dual DU's but we need to ensure that the size of 'Height' is allowed for either below or above the DU Bezel in the main MIP support and back-frame as the LCD Panel Height is greater than the DU frame BEZEL height. AN 18.5" LCD monitor (such as the HP W1972A) which is one of the later LED backlight units, will fit very nicely - caveat - but unfortunately it is still TN and still obsolete. Avoid ANY TN panel where possible.
There is NOT an IPS version of this specific size panel unfortunately !. - but...............

Luckily, with VERY very slight modifications to the DU Bezel units then a totally modern and fully up to date 17.3" High Res LCD Panel with FULL HD 1920x1080 AND IPS, AND eDP can be used. It can be used absolutely out of the box but ideally is does, as said, need a very very slight redesign of the DU Bezels but this will not be at all noticeable in use. will offer the details later if anyone is interested.

The Centre DU on the 737-NG is a total and utter Pain in the A$$ as it needs to fit between the (looking from the front) right hand edge of the Capt dual DU panel and the Landing gear lever frame. This is usually a case where the 2 lower standby display instruments are also driven by the same lcd panel. Normal internet standard search advise (often 12 years or more out of date) is to use a 16" 4:3 tv unit which is still crappy TN, terrible resolution and as difficult as rocking horse sh!t to get hold of. Luckily there are brand new 14" FULL HD 1920x1080 16:9 panels available that will do the job. They also, ideally, would need a very minor change to the bezel inner visual area but again, not noticeable in use. They can be used without any changes to the bezel (the 17.3 and the 14 respectively) and again would not be noticeable in use as we are literally talking a few millimetres only.

As an example of actual size (DISPLAY AREA) a standard 16:9 15.6" screen (ANY) would be as follows ... (Note - this is just used as an example of a common LCD Panels used in most laptops. It is actually of no general use for the 737 NG although it could 'possibly' be used as a lower EICAS with a dummy FO FMC. I am just using it as a reference as many people have 15.6" laptops and can compare dimensions at home.

Panel 15.6 diagonal at 16:9 aspect ratio
Visual area therefore = 344.5mm x 193.7mm

Please note.. in ALL the measurements I have used here they do NOT account for the size for the actual LCD PANEL Frame ! - most important in tight places.
That can be found though as, as I have mentioned above, only a few companies in the world actually make the panels. They are also a standard nowadays for connector and interface and also Size and resolution so it is possible to search for datasheets for the same type. I have most of the generic flavours if anyone needs them.

To hopefully assist anyone who wants to research and experiment with various panels here is a small spreadsheet I wrote that you can enter your basic LCD data and the critical measurement will be calculated for you.
All you need is the diagonal (ACTUAL DIAGONAL) of the panel which is usually what the monitor says - and the resolution. The spreadsheet will give you the actual VISUAL AREA of the panel. PPI (pixels per inch) is also listed for those interested. Here is the latest version I wrote.
monitor dimensions calculator.xlsx
(12.25 KiB) Downloaded 15 times
You can enter up to 4 units at a time for comparison as in -
Monitor calc - Joe.jpg
It is great for experimentation.

A real and serious note of caution though is to measure your own MIP bezels and also ALL the spaces to actually fit monitors as they DO vary between manufacturer, often by more than you would imagine. NEVER assume one manufacturers sim parts will fit another's. Sam at CockpitSimParts in the UK can make custom Bezels or whatever is needed. There are several other companies who will also do this.

Anyway, that's enough for now.
Hope some find the info useful.

I will add more info and upload datasheets when I get time.
“Everything in moderation, including moderation.”
“Experience is merely the name men gave to their mistakes.”
Joe (CISSP) -IT security consultant

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