A Homemade LCD Picture Frame From Laptop Parts, Part 1: Treasure Hunting & Research

Posted on: 2009-09-14 09:15:27

My wife had an old Toshiba A75-S213 that had some sort of "a battery/charging malfunction":http://www.hardwareanalysis.com/content/topic/38964/. The system was basically unusable. I ended up taking out the ram, the HDD, and the CD-RW drive for us in other machines.

Her screen was in very good condition (the whole machine was) so since I've had the builders urge lately, I decide to see what I could do to take the 15.4" LCD and actually convert it into a widescreen photo frame. This post (and probably the next several posts) will document my efforts.

To start off, we'll begin with some background at why this project might not be very easy and the processes used to figure out how we're going to attempt to get this done.

Desktop machines have (mainly) 2 primary interfaces for connecting displays: "VGA":http://en.wikipedia.org/wiki/VGA, and "DVI":http://en.wikipedia.org/wiki/Digital_Visual_Interface. These two interfaces are high-bandwidth and high-powered. They have plenty of room for things like shielding and whatnot. They also use a specific type of signaling to communication with their devices.

Laptops on the other hand, don't have room for that. Space is at a premium. They use something called "Low-voltage differential signaling(LVDS)":http://en.wikipedia.org/wiki/Low-voltage_differential_signaling over a 30-pin connector. This signaling system is much faster, but smaller and requires much less power-consumption. It seems as if there are 2 "standard" LVDS LCD connectors, a 30-pin and a 40-pin, but I've mostly seen 30-pin in my research. Here are some pictures showing the LVDS connector as well as gives you some idea of the size!

Bottom of the LVDS 30-pin connector: !sites/nickvahalik.com/files/lvds_bottom.png!

Size: roughly half the size of a VGA cable, but 2x as many possible pins. !sites/nickvahalik.com/files/lvds_size.jpg!

Side of LVDS: !sites/nickvahalik.com/files/lvds_side.jpg!

The gist of the two paragraphs above is that LCDs from laptops do not have the same connectors that your nice 24" widescreen monitor at home has. Not even close. Also worth noting is how power gets to these devices. All screens have a separate power supply for their bulb. In this case, the bottom of the monitor included a small (and very long) power inverter:

!sites/nickvahalik.com/files/cf_inverter.jpg!

Where my thumbs are is a 2-pin power output that plugs directly into the bulb. The other side has a power input. It's 7-pin, and also very small:

!sites/nickvahalik.com/files/inverter_power_side.jpg!

Now, this particular module used a set of reserved pins on LVDS connector to actually get it's power for the inverter. (I'm not entirely sure which pins just yet by number, but they are the "middle ones"). This is not going to be the case all of the time and so far doesn't seem to be the case at all when matching up motherboards to these monitors.

Okay, so first off, start by getting all of the part-numbers you can off of everything you are taking out of the laptop. For instance:

!sites/nickvahalik.com/files/model_and_revision.jpg!