Modding a 5" lcd to 5V?

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the antithesis
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Modding a 5" lcd to 5V?

Post by the antithesis » Sat May 16, 2020 1:57 pm

So I have various projects and for one of them I got a 5" back camera display because bigger, right? and it's nice and big but I have no real background in electronics so I don't know how to mod this myself. Fortunately, I found an instructables here on how to do it. Long story short, the guy hooked a USB battery pack up to the VCC of the I2C header on the board and it seemed to work.

My question is, is this at all a good idea? My board clearly labels it as VCC 3.3 and the data sheet of the main chip (AMT630A video display controller) has 3.3 power supply only. Therefore, 5v should be frying this thing, however slowly.

So is this at all a good idea or is there another way?

I did find another set of instructions for modding a 4.3" screen, but that required being able to figure out what the components are. the impossibly tiny writing is not legible even with a magifying glass.

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infinitLoop
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Re: Modding a 5" lcd to 5V?

Post by infinitLoop » Thu May 21, 2020 9:02 am

the antithesis wrote:
Sat May 16, 2020 1:57 pm
So I have various projects and for one of them I got a 5" back camera display because bigger, right? and it's nice and big but I have no real background in electronics so I don't know how to mod this myself. Fortunately, I found an instructables here on how to do it. Long story short, the guy hooked a USB battery pack up to the VCC of the I2C header on the board and it seemed to work.

My question is, is this at all a good idea? My board clearly labels it as VCC 3.3 and the data sheet of the main chip (AMT630A video display controller) has 3.3 power supply only. Therefore, 5v should be frying this thing, however slowly.

So is this at all a good idea or is there another way?

I did find another set of instructions for modding a 4.3" screen, but that required being able to figure out what the components are. the impossibly tiny writing is not legible even with a magifying glass.

so, i am by no means an expert, but here's my thoughts...

usually those screens take 5v or 12v in, so it would be pretty odd that it took in 3.3v at the main. it probably has a converter to drop it to 3.3 for the logic chip you mention, but it would be really hard to run the whole thing with that level, since you have backlight and other components that will draw current.

so, if it were me, i think i would just try the 5v in at the main. if it accepts 5, then it should work (*make sure you have a valid signal on one of the component-ins or its not going to come on, no matter what). if it will only accept 12v, then its just not going to power up, but you shouldn't be at risk of destroying anything (afaik). if that happens, then you'll need to find where the board can take 5v (IF it can, but most can, since the majority of stuff they tack on there run on that or lower). one way is to try and figure out the components by their markings (using a phone camera and digital zoom / brightness / contrast can help), or if you have a multi-meter, you can probe around with the positive pole until you find the ~5v one at one of the chips. It may take a connection straight to that, or you might need to pop that chip off and feed it to it (and of course if you are this far in, you are definitely at the point-of-no-return).

hope that helps. you could try posting pictures here too, if you can get good ones, and the forum can chime in.

.

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Re: Modding a 5" lcd to 5V?

Post by Dividion » Fri May 22, 2020 8:00 am

Did you check the composite screens list to see if the controller board has a known 5V mod? https://www.sudomod.com/wiki/index.php/GBZ_Screen

Otherwise, if you have a voltmeter, you could carefully check the pins of any 8-pin chips on the board to see if it's 5V. Usually it's one of the middle pins, and if you connect your 5V line to that pin you might be all set.

Or, if you have the room in your build for it, you could pick up a cheap MT3608 boost converter board, which can turn your 5V into 12V, and then run that to the board. https://www.amazon.com/unidades-MT3608- ... B07T7ZCTNK (you'll definitely want a voltmeter for that too, since you need to dial it to 12V)
Check out my store for GBZ boards and accessories: http://pocketadventures.com

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Re: Modding a 5" lcd to 5V?

Post by the antithesis » Fri May 22, 2020 9:37 am

So, the going consensus is hooking 5v to the I2C header am bad idea. I thought so.

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Re: Modding a 5" lcd to 5V?

Post by infinitLoop » Fri May 22, 2020 5:05 pm

the antithesis wrote:
Fri May 22, 2020 9:37 am
So, the going consensus is hooking 5v to the I2C header am bad idea. I thought so.
if it's only rated at 3.3v as you say, then i don't think that's the first thing i would try - if you're out of options and you don't mind risking it, well....

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