Help My screen wont turn on

[elusive-umbreon]

Ok after wiring the appropriate wires to the screen I found the screen dosen't even turn on and there is no sound. the gamecube is on because the LED is glowing and the fan is going, but the screen isn't turning on

its the PSone screen

What are the most common causes for the screen to not turn on and how do I solve them)

 

[brendanepic]

is it getting 7.4v

 

[elusive-umbreon]

Unless I've got my pinouts wrong (which is possible I'm going to double check using a voltmeter in a minute) I've got the following

12V to a voltage regulator with a 8V output to the 7.5V input for the screen

GND (mobo), GND (PCB found in the scart plug), GND (voltage regulator) and GND (screen) all connected together

5V out (mobo) to 5V in (screen)

Composite video out (mobo) to Composite wire (scart PCB) to Composite video in on the screen

Left audio out (Mobo) to left audio in (screen)

Right audio out (Mobo) to left audio out (screen)



- UPDATE -

I think I figured out why my screen isn't turning on, the voltage regulator is outputing 10.25V to the screen, thats way too much (highest I heard it can take is 8.5)

Problem is I don't know why its outputting 10.25v, it should be outputting 8V

I made up a regulator like this
http://www.rason.org/Projects/regulator/regulator.htm

where
R1 is 470 ohms
R2 is 220 ohms

the input is connected to the 12V output of the Regulator board from the gamecube with a 4ohm resistor between (to limit current to about 1A since it is a 1A regulator)

I used a 7805 btw





- UPDATE 2 -

I Heard a click and the screen powered on but only displayed a black screen (it glowed if that makes any sense) then all of a sudden the V regulator is only outputing about 3.15V the power regulator board is outputing a very small voltage at the 12V pin and ground is at 2.73V for some reason (not at the board though, its 0V at the gamecube but the regulator ground and the scart ground is all 2.73V

 

[elusive-umbreon]

Darkslkayer helped me and we figured out that instead of connecting everything that needed ground to ground I connected it to s-video c (chroma). I'm going to fix this as soon as I can but I haven't done so yet so that might not be the entire problem, but its looking hopeful

 

[Blargaman91]

Your voltmeter might be dying (battery). That can cause some wacky readings.

 

[elusive-umbreon]

I'm pretty sure things being pluged into s-video c when they need ground wouldn't help lol

either way as soon as I've got the wires sorted out again I can see if it is the ground thing or not

plus it doesn't have the low battery warning (its one of those fancy meters with a low battery warning thingy lol)

 

[elusive-umbreon]

Ok I want to replace the fuse but I don't know what value it is, does anyone know the value of that fuse that blows if you put more than 8.5V through the 7.5V in pin (I don't particularly want to put solder over it, just incase I make another mistake).

 

[L10N37]

try a a composite cable with male connector opposite end on another telly to make sure it's not your board. is the board cut? PAL boards output composite on pin 7 of that main IC not pin 9