Why dead horizontal lines are harder to fix…

July 21st, 2011

There’s a (relatively) well-known method of fixing dead lines on the DMG-01 (classic Gameboy) LCD screen which consists of dragging a hot soldering iron across the connection of the brown plastic connector with an epoxy blob, and the glass. The right spot in underneath where there’s normally a black rubber strip. This will reflow the glue, solder or whatever is used for the attachment, and the method can usually successfully fix dead vertical lines.

How not to fix dead horizontal lines on a DMG-01

Sometimes people ask whether horizontal lines can be fixed as well. I’ve always assumed that the connector on the right side of the screen, which would be at fault if there are dead vertical lines, is basically identical, and that the only problem with fixing horizontal lines is the more awkward position of the connection — the “ribbon” is connected on the bottom side of the LCD glass, so you need to fit the soldering iron into a small corner without damaging anything.

How not to fix dead horizontal lines on a DMG-01

However, the ribbon connector on the right side is different and more fragile. If you look at the top image, you’ll see a connector that looks brown. Technically speaking, this is called a flexible PCB (printed circuit board.) Just like on a regular, rigid PCB — like the display daughterboard itself — you have copper traces for connections and a green solder mask. The black blob in the middle is an integrated circuit, not unlike the chips you would see on any other circuit board, only that this one is hidden within a blob made of epoxy, and the circuit on the chip is connected directly to the copper traces, rather than using external pins soldered to a circuit board.

The right side connector has a similar flexible PCB, but the last stretch of the connection is made by a flimsy white plastic material which is easily damaged by the heat from a soldering iron. The actual connectors are not made of copper but possibly carbon or some other conductive material. My advice is, do not try to fix dead horizontal lines. You’ll likely just mess up the connector as seen below.

How not to fix dead horizontal lines on a DMG-01

5 Responses to “Why dead horizontal lines are harder to fix…”

  1. Eric says:

    Horizontal lines suck when they go out. I had 3 out near the top, but earlier today I was going to install a backlight and over ten went out. It sucks because I just put over $50 into the gameboy that was near perfect condition and probably won’t be able to use it. I really hate to ask, but does Anyone have a spare DGM that they wouldn’t mind selling?

  2. Crow says:

    Hi
    I’ve stumbled across your site by simply googling “attaching ribbon to lcd glass”, and now that I see the work you are doing here, I have an advice that may help you with this white ribbon cable: It is a special cable indeed, and not of the same type as the brown one. I have successfully repaired dead lines on LCD displays in some devices, including my collection of vintage Motorola StarTAC GSM phones, for which the LCD modules are no longer available anywhere.
    The trick in “resoldering” this type of ribbon without damaging it, is using an iron with temperature control. The bonding material on those cables melts at 190 degrees Celcius, and I had good success reflowing the glue when I set my Weller soldering station to 205 degrees. Simple soldering irons without temperature control heat up to more than 300 degrees, and this will destroy the cable by completely melting it, when I first tried doing this with a regular iron I had the same results as you are showing here.
    Anyway, I won’t be digging into the subject here, but if you would like more info or any tips, feel free to send me an email, I would be glad to help.
    Take care.

  3. Crow says:

    Also, looking at the last picture again, it is much more likely that the connection of the ribbon is problematic on the end that attaches to the green flexible PCB rhather than the LCD end. If you’ll look closely, you’ll notice that each trace on the white ribbon has irregularities and is not smooth on the PCB end, while on the LCD end the traces look smooth where it is attached to the glass.
    In those StarTAC’s I’ve mentioned, the problematic connection was always on the PCB end, and the traces looked just like in your picture here.

  4. Anti-Cheat says:

    Thanks for putting this here! It looks like a real pain to try and fix the connections to correct the horizontal line problem. Maybe I’ll give it a try once I have a temperature controlled soldering iron thanks to crow’s input. Thanks to this I won’t ruin my front board completely by using the iron I have now.

  5. penny wang says:

    One offshore pcb manufacture seeking for cooperation

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