inch lcd overheating

cyperghost

@hex I read your thread about discussing about the input terminal.... What do you mean with that?
@spruce_m00se I desoldered 2 parts of mine ...
I removed the power regulator and soldered it output (former 5V) to it's input (varible input 9V to 30V?) ... As I wanted to use the orignal input terminal I also desoldered the protecting diode (It was just a Si-diode) which needed 1,4 volts at least to get switched. So my LC is powered with 5,0V and is running fine. As hex mentioned it get just handwarm... much more heat is produced by the PieZero (= Super hot by all means)

Hex

My display IC AMT630a runs on 3.3v

cyperghost

@hex But you don't have an external 3,3V converter, I guess :)
I used an voltmeter to get the 5V source from the stepdown converter and removed the whole IC and then connected input and output pad...
I also have an AMT630a but I think there is a second regulator from 5V to 3,3V onto the board. Because mine is running best at 5V

Can you please post a picture about with your modification done to the PCB?

Hex

@cyperghost Can you post a photo of your LCD board?

spruce_m00se

@cyperghost mine also has a 3v3 regulator for the IC,
I didnt solder to the original input wire, I just soldered 5V to the opposite side of the diode in order to avoid its votlage drop, I soldered directly to the +ve leg of one of the caps before where the original 5V regulator was, and soldered its input to its output pads as you described.

mine gets so hot that you cannot touch it, it literally will burn you.
I should have tested it before I modded it, maybe it was shite from the begining

Hex

The overheating happens because you are supplying 5v to. 3.3v ic. If you have a 3.3v regulator, try that. I specifically got those from adafruit..

cyperghost

@spruce_m00se @Hex
That's not my original build as I need to open it first, but this is the exact board layout. Before I removed the IC I plugged in 12V and I measured 10,6 and 2x 5V on the three pins... (I can't remember exactly maybe it's the last pin on the left, the right side is 4 times ground).

So I brigged them all. As I did power on the device the picture wasn't sharp and if there was quick color-change then the picture blurred. So I removed the diode and bridged it's pads to win 1,2-1,4V and to have full 5V power. And this works perfectly so far.

I think there is annother regulator next to the 331 impedance ... and this might provide 3,3V but I didn't measure :) All in all the build is going well ... "handwarm" the hottest part is the PiZero SoC itself.

spruce_m00se

@hex alt text

Please explain your logic,
I have highlighted the 5V path in yellow, you can see I have joined the input and output of the 5V regulator, this is what took the original 12V and dropped it to 5V.

You can see that the 5V was feeding the 3.3V regulator. As far as I know, the 3.3v regulator was powering the MCU.

If I am incorrect and you know something that I dont then please let me know.

Hex

@spruce_m00se Do you have a volt meter?

spruce_m00se

@hex yes, thats how I know the 3v3 regulator is giving 3v3 to the MCU.

cyperghost

@spruce_m00se Thanks for the tipp with den capacitator. I solderd one directly to 5V/Ground inputs of the LCD-driver board. Now the heat is going down.
It's a 2,2nF ceramics caps.
The impedance produces a bit of heat. As I power the Pi0, an I2S, an USB hub and the LCD from the same powerline... there was some ripple in the impedance next to the 3,3V regualtor.