Hardware GBA Backlight! (AGB-001)

ServenIkhana · Mar 27, 2017

davidmorom said:
Hi ServenIkhana.

Yes, there are about 13.5V on the D1A pin, but after connecting the LCD backlight the voltage drops to 11V, because it cannot supply enough current. LEDs are non-linear devices, so altought it could be hard to believe, there is a big diference in brightness and current between 11V and 12V. Unfortunately, there is no point inside the gba with 12V, capable of supplying enough current for getting the LCD maximum bright level. And that's why external circuitry is needed.

Referring P1, I can't tell if it is mandatory to isolate it (using my 12V step up regulator I can assure is mandatory to isolate), because as soon as I received my adapter I cut the trace (just to be safe). But there are people complaining about the console turning off after soldering the cable, so I asume this could be the reason. Anyway, I highly recommend you to isolate it, to avoid shorting the 5V rail with the 13.5V one. In the 32 pin adapter I have is very easy to do, I attach a photo showing where to cut (don't know if yours is different).

After cutting that trace, the backlight will no longer be powered trough the 5V rail (it will stop working), so you can connect it to wherever you want (3.3V, 5V, D1A...).

Ok, thanks.

I have the same adapter so for avoid problems initially I will cut that trace and solder P1 to D1A. If the brightness isn't enough for me I will try your solution, but is unlikely since I'm used to use screens with not much brightness.

Have you considered selling these PCBs or sharing the schematics?

The input for the step-up converter is the 3.3v regulated rail or the raw batteries?

davidmorom · Mar 27, 2017

ServenIkhana said:
Ok, thanks.

I have the same adapter so for avoid problems initially I will cut that trace and solder P1 to D1A. If the brightness isn't enough for me I will try your solution, but is unlikely since I'm used to use screens with not much brightness.

Have you considered selling these PCBs or sharing the schematics?

The input for the step-up converter is the 3.3v regulated rail or the raw batteries?

Before cutting the trace, connect the screen and try it, to see everything works fine . If the screen lights up, that means it is powered trough the ribbon. After that, if you want a bit more brightness, proceed with cutting and soldering.

The regulator is powered trough the 3.3v line, because it needs a minimum of 2.7v. This is 1.35v per battery, so with 1.5v batteries, after some discharging it would stop working. With 1.2v Ni-MH batteries it won't work.

I make PCBs manually at home, so I don't sell them because it takes me too much time to make them. I can share the schematics if you want.

On ebay there are ready to use step up modules. For example: http://www.ebay.es/itm/Elevador-Ten...749478?hash=item33b0746266:g:cVUAAOSwqYBWo8yd
With this you can get the maximun brightness level, but not the brightness control, obviously.

bcoyle · Mar 27, 2017

I picked up a "Type A" screen with a 40 pin cable for my GBA via HHL - I installed it without any soldering. When turned on the screen is bright but washed out. It looks correct when viewed at a sharp angle from above.

Do you think I need to solder P1 to DA1, or simply adjust the trim pot possibly?

Thanks

davidmorom · Mar 27, 2017

bcoyle said:
I picked up a "Type A" screen with a 40 pin cable for my GBA via HHL - I installed it without any soldering. When turned on the screen is bright but washed out. It looks correct when viewed at a sharp angle from above.

Do you think I need to solder P1 to DA1, or simply adjust the trim pot possibly?

Thanks

Type A screens are not fully compatible with 40 pin motherboards. Soldering the cable will give you a brighter backlight, but the colors will remain the same. Adjusting the pot won't change too much either. To make the screen compatible with the 40 pin board, you must do the following:

1. On the cartridge slot side of the board, remove the following components: R16, R17, C33, C54 and Q3.
2. On the other side of the board, solder a thin cable between REVC and P2-VEE.
3. Reassemble the screen and power the console. Adjust the pot if needed. The image should be perfect now.

This method makes a 40 pin motherboard behave exactly as a 32 pin one. It is taken from this tread: https://gbatemp.net/threads/40-pin-gba-with-white-tab-lcd-perfect-solution.448597/
Discovered by malheur and perfectioned by gaggi. I tested it myself and can assure it works nicely.

Here you can see pictures of the process: https://circuit-board.de/forum/inde...Mod-AGS-101-Display/?postID=593578#post593578

Brenex · Mar 27, 2017

Hey everyone! I have a 32 pin board and just saw my SP is an AB ribbon type screen with the brown connector. I came across some websites that say 32+AB comes out looking poor. Is this still the case or is there soldering that can correct this? I just see in the recent posts that 40+A is the one with significant workarounds needed to make it look good.

davidmorom · Mar 27, 2017

I'm afraid I can't help you. All the screens I tested were white tab ones. Maybe someone else can give you some advice about it.

If you already have the screen, I guess you don't loose anything by giving it a try. If you do it, please tell us your results, so we all can learn a bit more about screens compatibility.

bcoyle · Mar 28, 2017

davidmorom said:
Type A screens are not fully compatible with 40 pin motherboards. Soldering the cable will give you a brighter backlight, but the colors will remain the same. Adjusting the pot won't change too much either. To make the screen compatible with the 40 pin board, you must do the following:

1. On the cartridge slot side of the board, remove the following components: R16, R17, C33, C54 and Q3.
2. On the other side of the board, solder a thin cable between REVC and P2-VEE.
3. Reassemble the screen and power the console. Adjust the pot if needed. The image should be perfect now.

This method makes a 40 pin motherboard behave exactly as a 32 pin one. It is taken from this tread: https://gbatemp.net/threads/40-pin-gba-with-white-tab-lcd-perfect-solution.448597/
Discovered by malheur and perfectioned by gaggi. I tested it myself and can assure it works nicely.

Here you can see pictures of the process: https://circuit-board.de/forum/inde...Mod-AGS-101-Display/?postID=593578#post593578

Thanks for this! I also found this - https://www.reddit.com/r/Gameboy/comments/5r8i0e/ags101_gba_mod_image_retention_fix_40pin_white/
Still waiting for a few items to arrive before I work on this mod again

geyser · Mar 31, 2017

there's always a simple solution:
WHITE tab w/ 32PIN combination
BROWN tab wi/ 40PIN combination
+ standard P1+DA1 soldering

works great for me

no ghosting / image retention or else after 30+ GBAs modified

davidmorom · Mar 31, 2017

geyser said:
there's always a simple solution:
WHITE tab w/ 32PIN combination
BROWN tab wi/ 40PIN combination
+ standard P1+DA1 soldering

works great for me no ghosting / image retention or else after 30+ GBAs modified

White tab screen + 40 pin motherboard + removal of R16, R17, C33, C54 and Q3 + wire from RECV to P2-VEE gives exactly the same quality as the original AGS-101, and is a very easy to implement mod. If someone have a white tab screen, and can't get a 32 pin board (like me when I did the fisrt mod) this a perfect solution. I wish I had known this by then.

Brenex · Apr 4, 2017

Brown tab + 32pin with P1 wire soldered on to DA1 works fine. All you have to do is adjust the voltage potentiometer.

shadowfax1007 · Apr 7, 2017

So I'm trying to do the backlight mod but all I'm getting is a black screen. I can hear sound and there is a green light on the motherboard but no display.
I ordered this screen. And this adaptor.
And here is everything hooked up.

It's a 40pin motherboard.

I'm devastated it's not working and really want to get it fixed up asap.

EDIT: Looking at the AliExpress screen, it has a white tab. Will that be an issue with a 40 pin board?

EDIT2.0: Looks like I'm an idiot and had the ribbon cable in back to front. Screen is still super washed out though.

ltsheppard · Apr 7, 2017

Try adjusting through the potentiometer.

If that doesn't work, solder a wire from RevC to P2-VEE and desolder components C33, C54, R16, R17 and Q3.

Plstic · Apr 8, 2017

Kitsch-bent has them in stock now. Gonna grab a gba from a convention tomorrow and try this mod out.

Brenex · Apr 18, 2017

davidmorom said:
I make PCBs manually at home, so I don't sell them because it takes me too much time to make them. I can share the schematics if you want.

On ebay there are ready to use step up modules. For example: http://www.ebay.es/itm/Elevador-Ten...749478?hash=item33b0746266:g:cVUAAOSwqYBWo8yd
With this you can get the maximun brightness level, but not the brightness control, obviously.

Can you share the schematic for this please?

Also, I didn't have to isolate my 5V and have had no issues with my 32 pin adapter and AB (brown) tabbed screen after adjusting the potentiometer. See blelow:

davidmorom said:
But before doing that, I had to cut on the adapter the trace that goes from P1, to 5V, to prevent shorting the 5V rail to anywhere else. I read people saying that after soldering P1 to D1A, the console turns off. This is because the P1 on the ribbon adapter needs to be isolated from 5V rail first.

davidmorom said:
Referring P1, I can't tell if it is mandatory to isolate it (using my 12V step up regulator I can assure is mandatory to isolate), because as soon as I received my adapter I cut the trace (just to be safe). But there are people complaining about the console turning off after soldering the cable, so I asume this could be the reason. Anyway, I highly recommend you to isolate it, to avoid shorting the 5V rail with the 13.5V one. In the 32 pin adapter I have is very easy to do, I attach a photo showing where to cut (don't know if yours is different).

After cutting that trace, the backlight will no longer be powered trough the 5V rail (it will stop working), so you can connect it to wherever you want (3.3V, 5V, D1A...).

davidmorom · Apr 19, 2017

Here you have the schematic and the board layout I used. They are in Eagle format. In case you use a 12V regulator like the one I used, I can assure you that isolating the 5V rail from the backlight power supply is absolutely mandatory, otherwise the current out of the regulator could damage the 5V of the GBA board.

If you want to use this circuit, you will also need a Microchip PIC programmer and the HEX file for the microcontroller. I can also share this if you want.

Brenex · Apr 19, 2017

Oh great! Thank you for the upload! I'm just getting in to electronics more and would love to look at it and learn some more. I've done a few projects already and I want to keep going with it. Can you send me the hex file too please?

rad3ds · Apr 20, 2017

I'm amazed! Good job davidmorom!

davidmorom · Apr 22, 2017

Brenex said:
Oh great! Thank you for the upload! I'm just getting in to electronics more and would love to look at it and learn some more. I've done a few projects already and I want to keep going with it. Can you send me the hex file too please?

Here you have.

isoboy · Apr 22, 2017

I'm using this and it's just....godly. Don't hesitate.

kongolomo · Apr 23, 2017

Howdy folks,
pretty late to the game but I recently unearthed my GBA and fell back in love with it.
I stopped playing it right about after metroid fusion, so i do have some gems i have never experienced (zero mission, minish cap, mario advance 4, e.t.c.) and i am more than hyped to start going to yard sales and flea markets to hunt down all kinds of fun gba games i never had.

Anyway, lets not waste our time here.
I do have a 40pin Motherboard, ordered a white tab screen and a "40pin type b" cable, tri wing and a glass lense.
I did read the whole thread around here and I think I'm pretty confident I'll be able to set this up properly.
However I'd love to ask you guys a few questions before I actually do anything just in case I mosunderstood some of the things I've read here...
Can I easily damage anything in there? Are there certain conditions when doing all this that I should definitely avoid?
Oh and also: With my screen and adapter combination there should only be a need to solder the red cable if I want higher brightness right?
I don't have to do any of that de-soldering stuff?

This thread has been such a great read and inspired me to do this little project so thanks to all of you guys. You are amazing.
If my electrical engineer dad would know that his son, who was always bored and unpatient when he tried to teach me such things, would one day start playing around with motherboards, 40 pin cables and soldering irons he'd be so proud :-D

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