the psychotic neurotic

Great – I have the graphics tablet and a suitable monitor, time to get out the tools and see what I can make.

Let’s see what the LCD casing is hiding: two phillips screws at the bottom of the back cover hold it in place; insert a small screwdriver into the crack around the edges and ease the plastic clips holding the front fascia aside – one clip on the sides and the bottom and four on the top. Et voilà, the front fascia is released. Four more phillips screws release the control button PCB from the front fascia.

Yet another four phillips screws hold the LCD module to the back casing. Remove these and the guts can now be lifted out of the case and now the monitor is free from its plastic prison. Hurrah!

Before proceeding I powered the monitor back up just to check I hadn’t broken anything. I hadn’t.

Time to flip the monitor over (CAREFULLY), lay it on some bubble wrap to protect the delicate LCD module, and take a

look at the brains. The labels show the LCD module is manufactured by Sharp. This is good – Sharp make some quality screens.

The circuitry is protected by a steel cage; a separate cage protects the potentially dangerous power cables feeding the backlights. Five phillips screws hold these cages in place and are easilly removed.

In the center is the main controller circuit board. The LCD module is connected to the controller by three FFCs: a 30-way white one on the right and two 50-way orange ones at the top (marked in green in the picture). The front control PCB also connect to the right of the control PCB (blue circle) and is easily unplugged.

The inverter board that powers the backlight is connected to the main PCB with a 10-way connector that passes through a ferrite ring (see the orange circles). I’m not sure why the inverter board needs ten wires going to it – I assume it is for control signals to control the baclight brightness, but I could be completely wrong. This monitor has two backlights – at top and bottom – and plug into the inverter board on the left (yellow circles). This arrangment is pretty convenient – if I decide to keep the CCFL backlighting then I can move the inverter board (to help reduce any interference with the graphics tablet) simply by extending the wire between the two boards.

After unplugging all the cables (the FFCs are released by lifting up the small flap on each of the sockets and the other cables by a combination of gentle pulling and encouragement from a small flat screwdriver) two screws release the inverter board and three for the main board. The CCFL wires are routed and held neatly in place by some plastic clips covered in what looks suspiciously like masking tape, but I’m sure is in fact some high-tech adhesive material! Ripping this tape away reveals two small screws that hold the clips in place.

Ta dah! I have now turned my monitor into two piles of electronic parts. I’m even pretty sure I can put it all back together properly again!

Now I’m on a roll; I put the circuity into anti-static bags and set them aside out of harm’s way. Time to see how difficult it is to take apart the metal frame holding the LCD module and backlight assembly. As it turns out, not very difficult at all: eight small screws (red) and six metal tabs (blue – one is out of sight on the bottom edge) which are easily bent with a small pair of pliers. Carefully turn the whole lot right way up and remove the metal frame that holds the LCD module in place. Carefully (VERY) remove the actual LCD screen and lay it on a flat, clean surface well away from pets, children, siblings, parents – in fact away from anyone and anything. The CCFLs now slide out of the frame – treat these almost as reverently as the screen module – they are just as fragile, although somewhat more easily and cheaply replaced.

backlight assembly assembled

CCFLs

backlight assembly disassembled

As the last photo shows, the backlight gubbins is deceptively complex. The white plastic frame contains several sheets of acrylic, all of varying opacity and thicknesses: a thin white plastic sheet at the back, an 8mm block of transparent acrylic (on the top surface of which is covered by a pattern of small white dots) and then three more opaque thin plastic sheets. The good news is there seems to be plenty of room to wire up some LEDs if I decide to replace the CCFLs.

Oh bugger….

I did read Bhrazz’s opening gambit and Drew even reminded me on the Bongofish forums. Bhrazz tells us:

“Before taking things apart try the Wacom over the working screen to see if you get interference. If you then get interference after its stripped that at least implies that it can be shielded.”

Wise words indeed, and I did mean to do this, but I forgot. If you do get a lot of interference when both the tablet and monitor are complete and assembled then there isn’t much point in going any further with this monitor/tablet combination.

One of my father’s favourite phrases is “less haste, more speed”. I hate that damn phrase, I hate that my father seems to utter it when I’m already pissed because I rushed into something and screwed it up. AAARGH!!! And yet the phrase comes unbidden to my mind. Fuck it. I guess I need to put the monitor back together and see what happens – this really will test my ability to reassemble the monitor.

In the end I decided not to put the monitor back together completely, but only just enough to power it up and connect it to the computer – with plenty of insulation underneath to make sure nothing on my desk shorts the exposed circuit boards. I figured that this way, in the event of interference, I can easily disconnect the power to the inverter board to see if this helps.

As it turns out, I couldn’t detect any jitter, even at the edges of the tablet. This is great. I think I’m onto a winner with this monitor.

I can’t go much further with the build until I get some longer FFC extenders and couplers. Luckilly, the search has already been done for me, lots of vendors are listed here.

Join us next week for the next exciting installment.

Tags: cintiq, Compaq TFT5030, graphics tablet, intuos2, project log, wacom, Wapaq

This entry was posted on Tuesday, November 18th, 2008 at 3:32 am and is filed under Wapaq. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.