40 pin GBA with white tab LCD problem

Discussion in 'GBA - Hardware, Devices and Utilities' started by malheur, Oct 11, 2016.

  1. malheur
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    malheur Member

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    all problem solved!

    https://gbatemp.net/threads/40-pin-gba-with-white-tab-lcd-perfect-solution.448597

    please read my new thread.



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    IMG_6698.JPG

    hello.

    i've done this with 40 pin GBA with white tab AGS-101. soldering this and that something something and it seems ok at first.

    but of course i'm having a little trouble. like many people having as i search, the ghosting(image retention).

    there is some "afterimage" which bothers me yet endurable, but i have to say, this vertical artifacts makes me living in the 80s.

    of course not always does that. like the picture above, straight black line or box causes a lot. and it's not like ghosting(image retention). not afterimage. realtime.

    anyway, this problem is one of the 40 pin + white tab problems i guess. i just want to know, is there any way work perfectly in 40+white combination?

    i found "40pin(a)" "40pin(b)" cable. i hope this will be fine because seller sales 40 pin a and b seperated. actually it looks differently compare to each other or mine. 40pin(b) is the for white tab LCD (they call B for the white one. i'm sure) and it has two resistors on the cable which mine doesn't. will this work? anybody tried?
     
    Last edited by malheur, Nov 14, 2016
  2. montiebro

    montiebro Member

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  3. montiebro

    montiebro Member

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    Totally worth it though
     
    Last edited by montiebro, Oct 12, 2016
  4. malheur
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    malheur Member

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    thank you for reply. what happened other 2?
     
  5. montiebro

    montiebro Member

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    I have a post for one of them, after a minute of two of being on white lines start to show up on the bottom and soon the whole screen is messing up making it impossible to play on. The other and most recent one would after like 10 mins would start to get dark lines (you could still see through them, it was just a line of darker shaded pixels. That one is still playable though just not ideal. I was playing it yesterday though for a half hour and the lines didn't appear. I think it's a problem with heating because they go away when it cools down. This one might just fix itself hopefully.
     
  6. malheur
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    malheur Member

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    ok. recent result. i believe there is several ways to fix "washed out" issue.

    1. P2-VEE + GND : the way usually known as 103+gnd. but it is not the 103. 103 is the name of one of the cpu legs.
    my opinion : not so good. sometimes it gets noisy visual on some board. not recommend.

    2. U5-3 + FIQ : not many people knows this way. somehow it works but not as good as next one.

    3. REVC + GND : it is better than way 1.

    4. REVC + GND / V2 + P2-VEE : it is better than way 3. as far, it is most less ghosting(IR).

    IMG_6898.jpg

    IMG_6878.jpg

    compare to original picture, it is obviously better. yet, there is still ghosting(IR) if you know and care about it.

    if anyone want to know how shows other games, it's just can't notice any problem. only particular screen like straight line and high contrast does.

    IMG_6901.jpg IMG_6918.jpg IMG_6910.jpg

    so i just satisfied current fix, but still there is some ways to do might perfect. i will not, but i want to know someone do.

    IMG_6900.jpg

    as you can see, there is "C1" and "C2" in the ribbon cable. i thought C stands for Capasitor at first even though it doesn't make sense, actually it was stand for CUT. so you can cut the bridge pattern in there or soldering again if it doesn't affect.

    C1 is actually pin #30 in 40p gba side(P2-VEE) / #27 in AGS-101 lcd side(REVC).
    C2 is pin #29 in 40p gba side(VCOM) / #30 in AGS-101 lcd side(COM).

    C1 : i am not expert in circuitry and/or lcd, but i believe the designer of this ribbon cable knows what happens 40p+white issues and left there some modification points. as you know the pinout of 40p gba doesn't have REVC that required on AGS-101 lcd, but it is on the board. it's just not out on 40p connector. so you can cut the "C1" on the ribbon cable and wire up directly on board. that's one way to try. but on the "40 pin (B)" cable as known works perfectly(really? not sure) it just connected same as this.

    C2 : but this one on the "40 pin (B)"cable as i said, actually NC(not connected). so i don't know whats difference between VCOM and COM, but anyway you can try cut this one too.
     
  7. marcos862

    marcos862 Member

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    That's a great information!! I had problems with a 40pin gba and LCD with black tab, the backlight was very dimm and i didn't know how to solve it, maybe trying this "cut" can help.

    I get another 32pin gba and tried the same LCD and, initially, after i solder the cable from P1 to the left leg of da1, the gba doesn't turn on, so, i make it works cutting the C2, in the 32cable adaptor, because it was doing a "short", so, after i cut the C2, the LCD works perfectly.

    So, i think that trying the C1 or C2 in the 40pin cable can solve the previous problem that i had, i will try it and i will let you know.

    By the way... in the original thread (https://gbatemp.net/threads/gba-backlight-agb-001.328487) a guy, @KipMudz , share the pinout for the LCD and gba, and he basically try to connect the VCOM to COM and he report: "Darker image and some discolorations in the display", so, he recommends to leave this pins untoched, so, maybe we can start testing with the C2.

    If you want to review the @KipMudz findings... you can find it here: https://gbatemp.net/threads/gba-backlight-agb-001.328487/page-5#post-4384381
     
    Last edited by marcos862, Oct 17, 2016
  8. marcos862

    marcos862 Member

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    By the way... in the original thread (https://gbatemp.net/threads/gba-backlight-agb-001.328487) a guy, @KipMudz , share the pinout for the LCD and gba, and he basically try to connect the VCOM to COM and he report: "Darker image and some discolorations in the display", so, he recommends to leave this pins untoched, so, maybe we can start testing with the C2.

    If you want to review the @KipMudz findings... you can find it here: https://gbatemp.net/threads/gba-backlight-agb-001.328487/page-5#post-4384381
     
  9. malheur
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    malheur Member

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    awesome. i actually read that thread already, but didn't realize it's related somehow with this ribbon cable. even though i can't confirm @KipMudz's method causes any issue or not such as washed out or IR, but if i suppose it works perfectly, wire 'cutted-C1 to REVC' and cut 'C2' might working since it makes identical wiring with it.
     
    Last edited by malheur, Oct 18, 2016
  10. malheur
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    malheur Member

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    finally i have some time to mod, so i did the cut.

    1. no wiring at all and just connect : as you know, washed out and no ghosting(IR). for sure.

    2. no wiring + cut C2 : no washed out and no ghosting, but dimmed screen(unusually dark and POT doesn't affect) and show interlace line! i don't know what it is, and maybe can fix the dim but interlace line... it's just not work.

    3. cut C1 and wiring directly to REVC + cut C2 : same as 2

    4. cut C1 and wiring REVC + not cut C2 : same as 1

    ...so in my experience, i realize the fact that C2 line (vcom/com) makes ghosting but cut the C2 doesn't simply fix the problem. C1 line doesn't have difference it's connect with REVC or P2-VEE.

    now i even more wonder that ebay's "40pin(b)" switch cable or aliexpress' "40pin(b)" cable actually works without issues or not, and if it does, how.
     
  11. MenaceInc

    MenaceInc Newbie

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    First post here and just got my GBA working the way I wanted. I had this same combination of 40 pin motherboard and white tab screen and massive issues with ghosting/image retention like what malheur has shown in their photos. I got it fixed though after studying the pinout that KipMudz posted and the info from your posts malheur.

    What I did was:
    1. cut both C1 and C2 on my ribbon cable
    2. connected P2-VEE to REVC
    3. connected P2-VCC (beside P2-VEE) to GND (specifically pin 32 for the cartridge (my solder skills are not good enough for P1-GND)).
    4. make sure to cover cut C1 and C2 with electrical tape to prevent any accidental shorts

    I've attached how it looked when completed.

    So, yeah, thanks KipMudz, malheur and wiggy from HHL. It's been real fun modding and might do it again soon. Especially as I may have slightly, ever so slightly scratched the AGS-101 LCD when I was scraping the foam off...thankfully it's barely noticeable.
     

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