40 pin ribbon cable issue

Discussion in 'GBA - Hardware, Devices and Utilities' started by Localhorst86, Aug 25, 2015.

  1. Localhorst86
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    Localhorst86 GBAtemp Advanced Fan

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    Hello,

    I recently ordered a 40 pin ribbon cable from china and another one from 8bit evolution in the us to fit my original GBA with a screen from an AGS 101 model. The case is dremeled but when I fit the cable to the screen the screen lights up but the Gameboy logo is very faint, the colors are washed out massively. Using the potentiometer to adjust the screen hardly has any effect, wiggling on the adapter cable however will occasionally show me the full, vividly colored Gameboy logo, but I am not able to make it stay. does anyone lnow what I could do to fix this?

    this is the cable I ordered from the US, because at first I thought the Chinese cable might be broken, but they both suffer from the same issue. using the ags 101 screen on the original AGS 101 board works fine as well.

    http://8bitevolution.com/shop/accessories-miscellaneous/gba-backlight-40pin-adapter-ribbon/
     
    september796 likes this.
  2. dragongc

    dragongc Newbie

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    From my experience you need to match the AGS-101 screen to the AGB-001 motherboard. I originally tried a Type-A (white tabbed) AGS-101 screen with a 40 pin adapter and AGB-001 motherboard and got the same results as you, really washed out and faint with the potentiometer not doing anything.

    Once I used a Type-AB (brown tabbed) AGS-101 screen with the 40 pin adapter and AGB-001 motherboard, it worked. My theory is that the pairing must be as follows:

    32 pin + Type-A
    40 pin + Type-AB

    I've read other places that the other combinations do work, but require soldering extra connections and I wasn't able to verify any of that.
     
  3. Localhorst86
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    Localhorst86 GBAtemp Advanced Fan

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    Well, crap. Thanks for your reply, my screen is in fact a white tabbed one, so it seems I can't use it in my AGB-001. So this brings me to this question:

    how can I see if I get a model with an AB screen (brown tab)?
     
  4. rad3ds

    rad3ds GBAtemp Regular

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    I've pulled one of each type of screen from pearl blue GBA SP's. One thing i noticed, was the plastic under the paint of the two systems was a different color, which could be seen by like, looking at the inside of the battery drawer for instance. The one that gave me a white tab had like a sea green plastic, and the one that gave me a brown tab had a much closer color matched blue to the paint.

    I've heard the white tabs referred to as "Original" and the brown tabs referred to as "Third Party." I think it's mostly originated on Chinese sites calling them like that. It seems to imply that part way through the manufacturing run of the AGS-101, Nintendo switched who was making the actual part. I would guess this means that the white tabs come from earlier AGS-101's, and the brown tabs come from later models. I somehow doubt the plastic color difference I noticed is a sure fire way to tell the difference, but it's just what I've seen personally. I don't think anyone's even attempted to figure out how the serial numbers correspond to tab color, but perhaps they might?

    Also, fun fact, I think I figured why they call them B and AB. The two revisions of agb were 40 pin and 32 pin and came out in that order. So the 40 pin is mobo A, the 32 pin is mobo B. The White tabbed screens are called type B screens because they typically only work with 32 pin mobo. The Brown tabbed screens are called AB because they work on either. That's the easiest way of remembering it. It's also good to keep in mind as some ribbon cables out there may use this notation, as they may be picky about which screen.

    There do exist ribbon cables that adapt the B screen to the 40 pin mobo, but I believe it requires some additional circuitry either on the ribbon cable or on the mobo to make it play nice and even then, I've heard mixed results, but it's hard to tell if people were actually using the right ribbon cables so it's hard to say. Here's an example of a really fancy brightness controlling ribbon cable that adapts a type B white tabbed screen into a 40 pin motherboard.

    http://www.ebay.com/itm/GameBoy-Adv...with-5-level-Brightness-40-pin-B/181797004647

    Expensive example, but I'm sure you could find something that fits your situation if you look around more or message the lee_chan guy or someone else who sells. You can see he mentions that it's for "pin B" Basically have to pay attention to the tab color when you're using a 40 pin mobo, and be sure to get a ribbon cable that plays nice with that specific screen. If the ribbon cable doesn't mention anything other than being "40 pin" that means it's for brown tab screens, some may call this something like a 40 pin AB connector, if it is for white tabbed B screens, it will usually specifically mention it, and it's generally seen as less supported and much more picky to get working, from what I hear.

    Above, dragongc referred to the white tabbed screen as "Type A" and I believe that was incorrect, and because this honestly gets pretty confusing. The two types of screens are type AB which are brown, and type B which are white tabs. There is not a Type A screen. Also perhaps worth mentioning, though not as directly related to your case, some people have complained that even though AB screens are supposed to be good to go with EITHER mobo type, they tend to be a lot harder to get to work with 32 pin mobos, so your safest best for 32 pin mobo is type B white tab. I'm going to be putting an AB screen into my 32 pin AGB later today if I get around it, was planning to anyways, will edit in how that goes for me in case anyone happens to be reading this just trying to sort out these crazy screen names :D
     
  5. Shadow#1

    Shadow#1 Wii & 3DS Softmod Expert

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    how do u know its a "white" or "Brown" tab? I bought a full kit with screen a while back and now found out about the new ribbon cable with switch that i was to upgrade to
     
  6. rs1n

    rs1n Advanced Member

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    Not sure if this is still relevant, but here's an explanation regarding the connectors:
     
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  7. slaphappygamer

    slaphappygamer GBAtemp Maniac

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    Thanks for sharing this. I bought a screen and a gba. I'm not sure what type gba motherboard or ags101 screen type I'm getting. I'll be sure to watch this again before o order my adapter. Awesome!
     
  8. marcos862

    marcos862 Member

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    Hi!!

    What you have said is not completely true, i have a ab lcd (brown tab) with a 32pin gba and it works perfectly, but, as you said, i need to make some modifications to the cable adaptor, i just cut off the C2 connection in the cable.

    For the problem that you have in your lcd, washed out colors, you can try this:
    http://gbatemp.net/threads/40-pin-gba-with-white-tab-lcd-problem.444675/#post-6746856

    There is a plenty of information about this mod in an old thread that is:
    https://gbatemp.net/threads/gba-backlight-agb-001.328487