MKnes worklog! (starts page 2)

phantom92opera

phantom92opera

Member
I ran the composite video (the pin under the where the RF box used to be) from my NES into the simple amplifier circuit (the one with the 4401 NPN transistor) and the signal going in and coming out fluctuates. how can i smooth it and get it to stay on one voltage? The psone screen it is hooked up to is flickering the whole time in sync with the voltage movement which makes me think they are related. basically the screen and lights blink and after shining bright, a frame from whatever is plugged in shows up.

If anybody could point me in the correct direction as what to do in order to get a functioning portable i'd be appreciative.
 
Re: video issues

Try a capacitor on the video line? (I have no idea if this will just make it worse, it's just an idea)
 
Re: video issues

I don't know if this will work for you, but the last amplifier circuit I built I had a similar problem. It wasn't a video circuit, though. When looking at the flat face of the transistor, I touched my multimeter probe to the leftmost AND center legs of the transistor. It made my output a lot stronger, so I stuck a jumper between them. It works great. I don't know if it'll work for your problem, though.
 
tried capacitors, and jumping which stopped the blinking but then I didn't get any picture on screen. any other ideas?

i hooked up the video out from the NES to an LED and it faded then brightened, then faded. something is definately up. Could it be the NES itself? Would someone please check their NES and see if all video out signals do that on the NES without the RF box?

Thanks,
Phantom
 
Re: video issues

out or in?
ive tried 100 on both, nothing happened, the closest i have is 68, i'll test it and let u kno

UPDATE tested with 68, didn't stop the flashing, the screen connects then flashes at 1s intervals, it is quite frustrating as you can hear the flashing too, the lights move with the screen (they shut off, then come on) etc. because the composite picks up, then drops, then picks up, etc

this is because of the cycling voltage the NES is outputting (i'm almost certain).
My question is, is this normal for the NES and how do I correct it?
 
Re: video issues

Do you still have the power LED hooked up to the NES? And is there a game in the cart slot? To me, the fluctuations right off the composite line sound like what happens when the cart isn't being read, how it just all flashes in perfectly even intervals.
 
Re: video issues

i tried new cart slots, i will try shifting them a bit and see what happens, the power led is not attached but the entire board gets power (multimetered that sucker to the end of the world). yes there is a game in the slot, (Dragon warrior iv!), i tested other games too, i will experiment with cart slot mounting and positioning as well. Thanks for the tips, i will update soon
 
Re: video issues

A/V signals (Actually I'm not sure about audio but definitely video) need to be at 75 Ohms. If your wires for the A/V signals are too long, then that could be your problem.
 
Re: video issues

Toast, putting a 75 ohm resistor on the line doesn't make it 75 ohms, it reduces it by 75 ohms. If the signal isn't 75 ohms, it doesn't usually flash like that. It's more common to be a steady signal, just full of static or extremely washed out. I've got an RF modulator that actually lets me adjust the ohms, and that's what happens when I dial it off 75.
 
Re: video issues

Tibia wins! The angle at which the cart was projected from the slot was causing reading issues. I taped the cart close to the mobo to see if that would do anything and low and IGNORE it read just fine ouputting a smooth signal. My dilemma now is how do I ensure the cartridge will enter properly when I make this portable? (mounting techniques?)
 
Re: video issues

budnespid said:
Mount it with some sturdy L brackets.
Click to expand...

Yes. L-brackets are great for making sure the slot doesn't move inside the portable. You can also use them to make guides for the cartridge to keep it in the position. I can post some pictures sometime tomorrow, if you don't get what I'm trying to say.
 
Re: video issues

Alright guys, this will be my 2nd worklog and hopefully my first portable (my first worklog on BenHeck was deserted). I am making an NESp, entitled the MKnes (my initials). The case is the following
vtech-baby-laptop.jpg
.
ignore the screen. it's already removed. i am using the base (it looks like mickey mouse) so think of it like this, a right side up mickey mouse, controls where the ears should be. Dpad on the left, ab buttons on the right, start select buttons lower right, speaker lower left (mono.)

Quick question, according to ben's book, when i do mono i need to jump hps, hpl, and hpr, but i want to put in a headphone jack . can i use a regular jack from radioshack or do i need the one from the psone/zenith screen?

thanks and stay tuned,
Phantom
 
http://img192.imageshack.us/img192/1381/173824.jpg
bondo'd controls, still need sanded, also gotta install screen panel (zenith)

http://img62.imageshack.us/img62/5513/173852.jpg
back panel, had to seal up some holes just to get a nicer finish. cut a space for the cart slot to come out of the bottom, to get the cart to lie flush i had to cut alot of plastic off, i have some engraving plastic to replace the panel (it'll lie flush hopefully)

http://img696.imageshack.us/img696/6312/173928.jpg
cart will be centered (this gives ya an idea,) it barely sticks above the case from the front.

http://img194.imageshack.us/img194/7048/174022.jpg
a general idea of case with screen panel (not connected yet) i have to seal off the holes at the bottom of the screen, they are irritating, unless you guys can come up with any ideas? lemme kno!

also if anybody could answer the headphone question in my last post that would be great!

thanks.
phantom
 
Bridge the pins, then split the audio going to the speakers with a switch. One going to the speakers, another to a headphone jack.
I may be wrong though.
 
bassmasta said:
Bridge the pins, then split the audio going to the speakers with a switch. One going to the speakers, another to a headphone jack.
I may be wrong though.
Click to expand...

yeah but then when you plug in the headphones speakers still run. right?
 
yesm. installing a switch is an extra wiring and case burden... usually u can just plug in headphones and the audio routes to the headphones and the speakers don't make sound, whereas with your method i have to put in headphones and hit a switch.... see what i'm gettin at?
 
Sorry, I just remember reading that if you don't bridge those pins, the system thinks a pair of headphones is connected and won't run the speakers.
 
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