Screen Flickering (NESp work-in-process)

mattb419 · Post by **mattb419** » Fri Sep 30, 2005 10:33 am

Hi All... First post for me, but I've been following this site for a few months now. I have been working on a NESp on and off since then (I'll try to post some pics in a bit). My problem has to do with the picture on the screen... the LEDs work fine, and the picture is there, but it isn't stable. It jitters a bit. I'm leaning towards a bad solder connection, but can anyone else think of another possible problem?

edit: put pics up on a temp web site, as well as a 7 meg video showing the problem I am working on.

edit again: I figured it out! sorry about the premature post. (the speaker is interfering with the screen... going to swap it out this afternoon.

|TA|SolidSnake · Post by **|TA|SolidSnake** » Fri Sep 30, 2005 12:30 pm

hey thats really nice, what did you use to make the case?
btw

I'm leaning towards a bad solder connection

i think thats your prob and also i noticed that the screen was bugging out when the music was going and when the music stop for a quick sec the screen was fine

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Fri Sep 30, 2005 1:09 pm

thats a great portable

i like how u used a clear front plate it looks even cooler that way

|TA|SolidSnake · Post by **|TA|SolidSnake** » Fri Sep 30, 2005 1:10 pm

i really like the case where did you get it or did you make it?

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Fri Sep 30, 2005 1:11 pm

its the handbuilt case from bens book

|TA|SolidSnake · Post by **|TA|SolidSnake** » Fri Sep 30, 2005 1:13 pm

cool well im getting the book in less then 45 min so i will be make one of them my self, how hard and what materials is need for one on those babys

mattb419 · Post by **mattb419** » Fri Sep 30, 2005 1:24 pm

it's the case from ben's book, as Turbo Tax stated. I thought using his design was a good idea for my first portable. I used a sheet of acrylic I bought from lowes for the front and back panels (bought it mostly because it was cheap... $8 and I still have about 1/3 of the sheet left for experimenting). SolidSnake, I didn't have too much trouble with the assembly, I just had to be patient and fight the urge to speed through things. The book lays things out quite nicely, just check the web site for an updated drawing of the left control board, and don't forget to pick up an LM317 regulator as well (it's in the instructions, but not the parts list).

continuing on with the screen problem... if I turn the volume to zero or unhook the speaker, the screen works fine. I tried putting in one of the old psone speakers, as I thought maybe the one I had wasn't shielded, but the psone speaker gave me the same problem. I am going to pull the screen and resolder all of the audio connections now...

codeman · Post by **codeman** » Fri Sep 30, 2005 1:25 pm

i'm in the process of building my own NESp as well. I got the screen and everything working perfectly, I just now need to make a case. Anyway, if you're using Ben's book...there's a modification you can make to the amplifier circuit. I used a 2N2222A transistor instead, which has the same gain, but it worked much better leaving out the 220ohm resistor going up to +5v. I think you're problem is with the video amplifier, so maybe that will fix it.

N Rage64 · Post by **N Rage64** » Fri Sep 30, 2005 1:28 pm

wow thats sweet

mattb419 · Post by **mattb419** » Fri Sep 30, 2005 1:33 pm

thanks for the tip codeman... I was contemplating heading down to radio shack this afternoon... now I guess I have a good reason to go.

mattb419 · Post by **mattb419** » Fri Sep 30, 2005 4:28 pm

welp... i killed it

I'm not sure what exactly I did, but now I have no picture or sound (I can still get the volume and brightness displays on the screen, so I don't think I've fried the screen... any ideas of places to check?

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Fri Sep 30, 2005 4:37 pm

cold solder joints between the grounds

mattb419 · Post by **mattb419** » Fri Sep 30, 2005 6:19 pm

Turbo, that was it. It's back up and running, but still the sound problem... I'll get back to it next week (family in town this weekend). Thanks for the help!

Also, I switched out the transistor in the video amp... seemed to improve the picture slightly, but didn't affect the flickering screen any.

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Fri Sep 30, 2005 6:58 pm

i bet its your battery do you havde he right kind of charger and does the pronlem lessen when the volume is down

mattb419 · Post by **mattb419** » Fri Sep 30, 2005 10:26 pm

I'm using a generic NP-F960 sony-type battery... fully charged - multimeter reads around 8.3 volts or so I believe... I thought it might be the battery earlier, so I took off the battery connection and am using a psone adapter (7.5 volts, 3A). Will this setup work with the NES?
Regarding the volume... if the volume is turned completely down, there is no problem with the screen (likewise if the volume is up and there is a section in the game where there is no music, it looks fine). So basically if there is sound coming from the speaker, the screen is distorted.
I have a 12v DC adapter laying around as well... should I try hooking that in to see if it fixes anything. I figure that would be plenty of power, plus the regulators should knock the power down to reaonable amounts, though it might generate a little more heat