Installing a new screen controller

    IF you haven't followed my recommandations about unsticking the metal plate from behind the screen, chances are you've heard a distinct crack, putting an end to its life. Don't give up so early, it's possible to put back a display on your machine. To do this, you will need an out of order 83 or 83 Plus (Don't go cut up a functionning machine, this would be stupid) which will serve you as an organ donor.

Comparative controller's study

TI 83

Reference: 6A04A
Picture:
Electronic scheme:

TI 83 Plus

References: T6A04, 6A04A
Picture:
Electronic scheme:

    A quick glance is enough to see strong ressemblances. In spite of a more tortuous electrical path in the 83 Plus' case and different references for the components, real ones are in fact very few and only affect open jumper's position in circuits, although they open the same ones. R22/R16 value is the same, despite of a different marking.
    Moreover, having examined other TI 83 Plus, it was possible to find the same controller reference as in the TI 83, connected to the discrete components of the TI 83 Plus, which proves their intercompatibility.

Transplanting a 83 video controller instead of an 83 Plus one

You'll need:
- A screen controller (screen itself, chip and components) in good state from TI 83 or 83 Plus
- Small soldering iron with electronic grade solder
- At least 25 cm of fine wire, or about 2 cm of flat wire (at least 17 leads)
- a penknife, small knife or stripping pliers

    If you followed as far as this, you may end up asking yourself why not simply exchange the glass part, which is the only damaged part of the TI 83 Plus. Let's push the controllers observation further; they're connected to the glass screen with a flat tape containing very fine and close leads, which you can see at the top of the pictures. After experiencing, I remarked these were very fragile, as conductors tear up easily, and are difficult to stick again, even if not torn. And in the case sticking wouldn't be a problem, liability of connection will be compromised. A simple method consists of using connections linking screen controller the the mainboard.

First step: getting rid of the plastic multi-wire connector
    Indeed, while more resistant, it suffers from the same problem as the other one on top of the screen, notably when it comes to usefulness after a successful "unsticking".

Second step: cleaning copper tongues
    It may seem trivial, but it's surprising to see how much people capable of forgetting this simple step and complaining about a bad solder's grip. I've done my cleaning by using a rotary metal brush mounted on a Dremel, which was quite dirty, as the gray marks around the connector may reveal on the first picture
.

Third step: tinning and soldering the new wire
    Begin by carefully cut 17 pieces of wire, about 1.5cm each. Strip them at each end from about 2mm. If you used flat wire multi conductors solution, strip them for 4mm. Why should you do this ? As you could observe it if you've done some electronics before, the step between the copper tongues is not standard, probably contrary to your flat wire, which will lead you to manipulate it to adapt it, in a case where some connections may be too small if you don't take this precaution.
    Then tin the exposed leads with solder. Next, melt a small amount of solder on each copper tongue from the controller and mainboard, forming a small dome about ˝mm tall. Hold the wire onto it, then melt the dome again, holding the lead in the liquid solder; if you done it neatly (don't take my work as an example ;-), your wire should be  tighlty soldered to the tongues. Now you only have to complete this step with each wire, then link them to the mainboard.
    Tip: if you take a look at the original connector while the circuits are still in the case, you'll see it's folded two times; ordinary wires don't have such a flexibility, and the same situation may wear out the connections faster. To correct this, lay the video card on the mainboard, screen facing you, unsoldered leads over mainboard's copper tongues. Now you only have to solder as previously indicated, then to replace all in the case. This way, connection wires will only be folded one time..

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