I need a lot of help (Me too)

cleavebledread · Post by **cleavebledread** » Tue May 16, 2006 7:43 pm

Where do I start....

I'm trying to make a pNES or NESp, whatever it's called, and I'm having some serious trouble here. I am using an official NES, no screen yet so I'm using a TV

So, My problems go as follow

First: I made the video amp. circuit according to what "The Book" says but I don't get video on TV (well I do, but its not playable at all, just enough to realise it's not just static)

Secondly: I don't get audio either, just sound and I can barely hear some music very faintly is I raise the volume to the max

Third: .....It doesn't work, I'm lost

P.S. : I don't use a remote control car battry, just some AAs

codeman · Post by **codeman** » Tue May 16, 2006 8:07 pm

ok...i'm not sure about the audio problem, but i'm also not sure how much the audio signal is amplified before it reaches the TV. The portable TVs and screens have their own audio amp to take care of that.

As for the video, the circuit from the book didnt work for me either. I had to change it around to get a good picture. First of all, try getting rid of the 220ohm resistor connected from +5v to the collector of the transistor. Then if you want, you can change the 33ohm resistor, which changes the contrast of the video. I used a 100ohm resistor instead, and it looked great.

Post by **CronoTriggerfan** » Tue May 16, 2006 8:18 pm

How many volts are you running the system off w/batteries? If it doesn't work w/batts, try using the wall adapter and see if you get a signal then. As for the NES as a whole, if it's THAT scrapped, I recommend just grabbing up an NOAC. They're actually easier to work with, and the wiring job doesn't have to be as elaborate.

Good luck,
CTfan

cleavebledread · Post by **cleavebledread** » Tue May 16, 2006 8:33 pm

@ Codeman

Well, that did help, a little, now the picture is a little clearer but still not playable. But now I am starting to think the reason I'm not getting a good signal is due to interference because when I unplugged my cables, I closed the NES and the TV screen flickered for a moment, I tried again and it did the same thing.

Any thoughts as how I might stop that

@CronoTriggerfan

Well It's powed by 8 AA batteries so it's on 12 volts, but I did try with 6 batteries to get 9 Volts and it didn't change a thing. tried using the original adapter but then the whole thing didn't work at all, the image I got was replaced by a grey bar on the TV

And yep, I just bought a Yobo NOAC on eBay but I would like to save the NES if possible (They are quite pricey here about 50$)

vskid · Post by **vskid** » Tue May 16, 2006 8:42 pm

It is called a NESp. Just say pNES, you'll know why it is NESp.

Post by **CronoTriggerfan** » Tue May 16, 2006 8:43 pm

If I remember correctly, the NES really doesn't like 9V very much. Try something like 7 or 7.5 and see if your results improve.

As far as audio, run it through an amp. I've got a nice little audio amp circuit somewhere, just gotta find it... If that doesn't work, your audio chip on the NES board may be damaged, and then you're in trouble.

CTFan

dajudge · Post by **dajudge** » Tue May 16, 2006 10:27 pm

Having a similar problem. Screen lights up but no game/audio. Iver replaced the 72-PIN and am now resoldering joints (basillcally rebuilding it). Can someone measure the volts going to the NES mobo from the pc board and tell me if yall are getting close ti 1.7v? Thanks.

chris

codeman · Post by **codeman** » Wed May 17, 2006 10:51 am

so...you're both regulating the voltage to 5v right? The RF box was also where the 7805 was if i remember correctly. The whole thing should be running off 5v...not 1.7v. I would also highly recommend doing the floppy cable replacement for the cartridge slot...it works so much better.

As for your video problem still, check all your ground connections. I forgot to hook up the video ground once and it gave me all sorts of weird problems on the screen.

arfink · Post by **arfink** » Wed May 17, 2006 12:50 pm

Oh yes, I have had this problem too. I, fortunately, have conquered it. Interference is part of it, because If you are running this off 5 volts and youre not using the power setup thats in the RF box, you will need to make sure you have anough amperage going to the NES. If your wires for the 5 volts and ground are really skinny (robbon cable?) it won't work too well- try using bigger wires. Seriously, the NEs takes enough juice that impedance can be a big problem.

cleavebledread · Post by **cleavebledread** » Wed May 17, 2006 3:27 pm

pNES, lol, but NESp said over and over....

Ok, from the 7805 I get 4,76 Volts and about 320mA but wierdly, I tried again and once I had perfect audio but no video so I think the video is the only problem

So you think that using a bigger cable would help?

Edit: Now I know how I got the audio earlier, I accidentally put the video cable on the ground section and then only the good audio comes out

Edit again: I tried to change the 33 Ohms resistore on the amplifing circuit by the biggest one I have, a 600 Ohms one and the sound got clearer and so did the video, I think I'll try to get a higher one when I can get some more[/i]

dajudge · Post by **dajudge** » Wed May 17, 2006 10:17 pm

Look on the motherboard where the video and audio and +5 v goes into. I screwed up the traces when desoldering and i think there lies my problem. I get 5v to the board, but only 1.7v from the video spot. I think it maybe a bad trace.

cleavebledread · Post by **cleavebledread** » Fri May 19, 2006 10:01 pm

well I get about 2.6V to both the video and audio but thats not a good example.

Anyway, anybody know if my problem is reparable or not.

When I plug the video, I get a very distorted signal and a strange buzzing sound over the music but if I change the value of the resistor (the 33 Ohms one) on the amplifing circuit to a higher one, the lower the buzzing gets softer.

4,76 volts and about 320mA go in the NES.

Anything flagranlty wrong here that I can't see or is the NES board just fried

P.S. Can somebody describe what the video signal should look like before being amplified (Like if you plug it the same way a the sound), that would help, Thanks