Almost all ebay screens can run off 3.7v

[andrewdorsey]

I'm sure a lot of you already know this, and maybe I'm the slow one, haha.

Made a discovery today. This information is not 100% confirmed true.

Almost all ebay screens have a regulator that takes 12v down to 5v or 3.3v

The bottom left of the regulator in this pic outputs 3.3v as it says in the bottom left of the regulator and based on that number is how many volts the screen can run on.


I used this 3.5" monitor from ebay.

The red dot on the resistor is where you can input 3v-3.7v (confirmed working)
3v makes the screen kinda dim but 3.7v works perfectly!
The yellow is composite video.

since composite can be found near the bottom of the board and the voltage can be connected from the resistor, I'm sure the top can be cut since power and video have been relocated.

 

[βeta]

I have experimented with this some. What I found was that the video quality deteriorated drastically once the voltage drops below 7v. Yes, it works at 3.7v, but it looks like flax.

 

[andrewdorsey]

Maybe it is just this model screen, but there was no change in video quality from 12v to 3.7v, haha. And if there was a change, it was so slight, hardly even noticeable. Besides, it is not that important for video quality to be superb on a 3.5" monitor haha

 

[Diminuendo]

good info, thanks mate

 

[βeta]

it is not that important for video quality to be superb on a 3.5" monitor haha

This is a terrible attitude to have.

 

[andrewdorsey]

Its all based off preference. Not trying to offend anyone here.

 

[andrewdorsey]

Did some more testing for fun and here are the results.

The top can be cut off with only a few relocations
Not like it is very significant...

The Blue circle is the regulator. That has to be rewired with just 3 wires in order for the backlight to work. The green is a trace that gets cut and needs to be rewired.

3.7v battery and switch on the back for testing

Confirmed working:

 

[ShockSlayer]

Fairly certain back in 2010 after I got home from MRCT I ran a 3.5" screen off of 3.3v. I think I documented it on here somewhere too. Also, if screen motherboard space is that important to you there's a link somewhere on these forums to the ebay ones with much tinier motherboards, about half the size of the one you have there. LCD is the same size, looks to be the same encoder chip and everything.

Gonna do some side by side quality tests later.

SS

 

[andrewdorsey]

Yes, I have seen those 3.5" screens with tiny boards. This was all just experimentation for sh@!#$and giggles, haha

 

[Luig]

I have a screen similar to this one. Is it possible to make it usb powered? 5v in other words and if possible, how would I go on doing something like that?

 

[Rohan Loomis]

yep i got this 5" TFT monitor from ebay here is the link:
http://www.ebay.com/itm/5-TFT-LCD-D...r_View_Monitors_Cams_Kits&hash=item3cd1999d74

on the board there is a 3.3v regulator and a 1.2v regulator. the middle pin of the 3.3v regulator is the place where you solder your 3.3v line. you don't have to mess with the 1.2v regulator as the 1.2v regulator runs of of the 3.3 volts.

here is a picture of me running it of my phone battery:

 

[public-pervert]

I can just see an OVNI.