# Thread: My solution to Auto Power ON Lilliput screen

1. Originally Posted by sivart321
I also have a dynamix screen that has a common power and source button.

I have found that powering it on, and then holding the power switch down for 4 seconds will turn it on.

Can anyone take a swing at what value capacitor should be used to give a momentary on of ~4 seconds?

I do not think it is as simple as assuming since a 1k uF cap gives you 1/2 second, that 8k uF will give you 4 seconds, right?

Thanks
Assuming the circiut is the same as the Lilliput...
You need to find out the series resistor on the board. This will be the resistor in series with the power button. Measure that resistance, R. The value of the capacitor C will determine the RC time constant, RxC=seconds. R in ohms and C in Farads ( or R in Mega-ohms and C in uF)

2. Resistor in series with the switch?

I am refering to the momentary on switch using a relay as posted just before my last post.

I am not sure if you are refering to the same thing that I am asking about.

I will be wiring this circuit directly to the power button on the button PCB with two wires and using the circuit to short those 2 pins for 4 seconds.

Are you saying there should be a resistor on the button PCB? I only see one notation (R1) below the only thing that resembles a resistor. It measures 0.10 on the 20k ohm setting, or 100 ohms.

Using what you said, I would need a 40k uF capacitor to get me 4 seconds of momentary on from that circuit? That seems like a big capacitor.

3. If the software fix outlined in this thread is working for most people, there should be a disclamer in this thread so that people don't do it when there is a simple setting fix?

What do you think?

4. I have modifyed my lilliput, and now I have a little disturbance....
The monitor works fine but every time I start the computer/screen the monitor shuts down for about 1-2 sec and starts up again...this happens after a few minutes.
Then some times it shuts down and doesn´t start again...but this does not happen often at all.

I have used the components thats specified in the description on first page in this thread, the cap is mounted with right polarity, the solderings are OK, I´m powering from CPU...

Is there anyone who has this problem? or anyone who knows?

5. ## Buttons all messed up

I think I may have put the button ribbon cable off by one as a previous poster mentioned...

I applied the mod (capacitor only) and lo the screen comes on automatically. The lights now stay on all thei time, the av/vga button now turns it on, the display button turns it off! None of the other buttons appear to work, including the power button...

I quite like it though, and it's back in the car now so unless I can find a good reason to fix it, it'll remain like that!

Have fun,
Darryl.

6. What about the software fix?

7. My problem is resolved now, I just dubbled the cap from 10 to 20 and decresed the resistance from 150k to 75k and that did the trick for me
/Rs!

8. unfortunatly not on mine

9. OK i tried the mod like ming with the 10uF cap and 150k resistor and all the lights go on, but nothing shows up on the screen, have I pooched the screen?

10. I just did coyote's mod and it appears to work fine (at least the auto-on part). when the cmputer turns on the screen turns on too. now the problem..... apparently it is stuck in Video2 mode (BTW - I also saw the Jurassic Park logo)... the buttons on the screen don't work, and apparently the remote doesn't either, i'm going to change the battery on the remote just in case. when the screen gets power it turns on for a very short time, enough for me to see that it says Video2 on the screen, then for a split second it displays the "No Signal" box and then it goes black..and stays that way.......shouldn't it detect that there is signal on the vga input and automatically change to that?

anybody has had this happen??? I would appreciate any help.

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