See post #2
Hi,
I've recovered a LCD from an old voip phone and hooked up to an arduino pro mini, using default liquid crystal sketchs, but it doesn't seem to work.
The backlight pins are leaved unconnected and the contrast is controlled with the PWM but I think this isn't a problem.
Any help is appreciated 
Front view:
Back view:
Those pictures aren't very helpful.
Upload the original pics to tinypic (no registration needed), and link to it using [img] [/img] tags.
Arduino14:
Hi,
I've recovered a LCD from an old voip phone and hooked up to an arduino pro mini, using default liquid crystal sketchs, but it doesn't seem to work.
The backlight pins are leaved unconnected and the contrast is controlled with the PWM but I think this isn't a problem.
Any help is appreciated
Front view:
Back view:
Those pictures need a little more contrast.
Connect the backlight. Some LCDs can't be used without one.
Connect a proper contrast circuit. The LCD will be blank if the contrast isn't correct.
Don
nothing attached?
To sort things out - this is the result of merging two almost identical threads.
There was no attachment in one and there were no pictures in the other.
- reply #4 goes with what is now the original post.
- replies #2 and 3 go with what was another original post and is now reply #1
Maybe we should start over.
Don
floresta:
Those pictures need a little more contrast.
Infinitely more, actually. 
The post without pictures should be deleted. Why the pictures need more contrast? I've posted them only for show the model number which is clearly visible
Arduino14:
The post without pictures should be deleted. Why the pictures need more contrast? I've posted them only for show the model number which is clearly visible
OK let's phrase this a bit differently. There are no pictures and there are no attachments. Nothing is visible.
Don
Arduino14:
Why the pictures need more contrast? I've posted them only for show the model number which is clearly visible
That is a subtle way of telling you that the pictures are not visible at all.
I suspect you may have posted them on a site on which they are "private" to your account.
OK, let's see ... "View Source": apparently they are on "postimg.org".
No, you posted the display page rather than the image, as an image. That won't work. Let me try:
Front:
Back:
That’s better! Unless postimg does something else sociopathic.
In the second post I see the two pictures..
To us they are not visible.
The link can be revealed by clicking the quote button, and following it will lead to the actual picture.
The ones you posted yesterday (which were visible) were too small to see any detail.
Paul__B also figured out how to get to the pics, and found a link to a jpg file, which is what you need.
(I can see the back in his post, not the front)
I have no doubt your image host offers you some help to link to your pics using IMG tags, you just need to look for it.
And i just told you you need to link to a picture and not to something else.
So check if the link you are using has a picture extension at the end, like jpg, gif or png (i don't know which extensions are actually supported).
Let's see if i can make that front visible.
Yep, to me that seems to work.
The forum software resizes the picture to fit the (my) screen.
MAS3:
The link can be revealed by clicking the quote button, and following it will lead to the actual picture.
Ah yes, I forgot that, though that is exactly what I have done in the past to reveal hidden things.
One has to remember that the primary function of sites such as postimg.org is to earn money through advertising, not to provide you with a service of displaying your pictures.
As such, the original link they give you - the two that Arduino14 posted, are deliberately mis-labelled as .jpgs but actually link to advertising pages. Well, I think they are, as I cannot of course, see the advertising. 
I picked the links to the actual images, but advertising sites frequently prevent display of the images unless they determine you have actually viewed the advertising page.
I still see no pictures in any post using Firefox, Chrome, or IE.
I've got Firefox pretty well locked down to eliminate ads etc but the other two are stock.
Don
Guys, I've fixed the two pictures, now should be visible to all! Meanwhile I've found the display manufacturer, it's SGD, but in its website I haven't found any documentation
Arduino14:
Guys, I've fixed the two pictures, now should be visible to all!
Well, I can most certainly see them.
"imgsafe" - more reputable site it seems.
OK - they are visible here now.
The second picture shows all of the earmarks of a Hitachi 44780 compatible LCD. One complication is that the pins are below and to the left of the display, and displays with that orientation frequently have a non-standard pin sequence. Fortunately your pins are clearly numbered so that shouldn't be a problem.
The first picture shows visible blocks on both lines of the display indicating that the contrast voltage is too low (with respect to GND). It's possible, but not likely, that the display is working but the improper contrast setting is obscuring the characters.
I repeat my recommendation that you start by connecting a proper contrast circuit and seeing if you can adjust the contrast, with no program running, so that one row of blocks is barely visible.
Your soldering techniques could use some improvement. Check this out: --> Common Soldering Problems | Adafruit Guide To Excellent Soldering | Adafruit Learning System
Don
As I write in my first post, I've tried to set the contrast using PWM, but the black squares are still visible.
Don't try to use PWM to set contrast, certainly if you're new to all of this.
PWM isn't an analogue signal, it's digital.
It doesn't do what the contrast pin expects to see.
So to get things working, just use the standard potmeter.
Once you've got it working, you can see if you can do the contrast thing in some other way, but forget directly "PWMming" into the contrast pin.
As I write in my first post, I've tried to set the contrast using PWM, but the black squares are still visible.
That's why I keep on recommending a proper contrast circuit.
Don