Question just operate a 5v screen with 3.3v

[groseil]

hello I currently have a screen card that works with a minimum voltage of 5v. So I had a question. is it possible to modify the board so that the screen can work with a lower voltage. I've never had to deal with this type of problem and I'm afraid of breaking my screen....

 

[Customledmods]

https://bitbuilt.net/forums/index.php?threads/running-screens-off-lower-voltages.2256/

 

[groseil]

yes, I have already seen this guide. I think I found the regulators?!? but I don't know what to do anymore.
the first on the left of the image = 5v
the second =3.90v
the third = 3.33v
the fourth = 3.90v

 

[Stitches]

Supplying 3.3v to the 3.3v inductor *should* work

 

[groseil]

so I connect my 3.3v wire to the 3.3v output of the inductor?
should I remove the inductor to test if it works? can my screen die?

 

[Stitches]

A mistake could kill the screen, yes. Removing the inductor isn't a bad idea, but you should first test to be sure that 3.3v input is enough to run the screen. If it works as expected, then you can remove the inductor

 

[groseil]

then... it works, the screen lights up but the charge and discharge module turns off and no longer powers anything. (he goes to safety I think)

 

[groseil]

knowing that I have kept everything, I am therefore not unsoldering anything.

 

[Stitches]

Did you disconnect the 5v wire when you added the 3.3v wire?

 

[groseil]

Yes

 

[JMCD]

Yes

Hi, do you have any photos of the board showing your modifications?

 

[groseil]

I put my 3.3v wire at the point drawn in red and I connected my gnd wire to a gnd location on the board. I didn't change anything apart from that.

 

[JMCD]

I put my 3.3v wire at the point drawn in red and I connected my gnd wire to a gnd location on the board. I didn't change anything apart from that.

I think that might be the input pin of that regulator not the output? Is it a 1117?

 

[groseil]

Yes

 

[JMCD]

Is it a fixed regulator or adjustable, fixed normally state voltage on them?

 

[JMCD]

 

[groseil]

it comes out 1.8v from the middle pin....

 

[JMCD]

it comes out 1.8v from the middle pin....

Sorry I thought you were providing just 3v3

I've edited my post above as I gave you incorrect advice

 

[Xyzven]

Not sure if this is a good answer but if you are using the PMS-Lite or PMS-2, you do know they have 5V regulated lines out right? You COULD try to use that line (provided you check it with the multi-meter). No guarantees it will be able to supply enough amperage though so YMMV.