It is currently Fri Aug 17, 2018 3:52 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 72 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
PostPosted: Thu Oct 09, 2014 6:05 pm 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
After some consideration, I'm going to try and hunt down a radial one instead, just so it fits into the slot in the RF modulator like it should. I feel like if I try to shape the pins on the axial one I have to fit, they're just going to snap anyway.


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 11:30 am 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
All right, I got my hands on a radial 2200 uF/25 volt capacitor, installed it and... no effect. Those damned oscillating waves are still over the screen.

This is ridiculous now. I've done pretty much everything I can to this thing to try and correct this problem and nothing. No dice. What else could this be?

If anyone else has a theory or a suggestion, I'm wide open. Heh.


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 11:42 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7392
Location: Seattle
I still think you report back on any of my suggestions :P


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 11:55 am 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
Unfortunately, I don't have an AM radio to try that experiment and...

Quote:
tap a small capacitor (maybe a 100pF?) between Vcc and Vout (pins 40 and 21 on the PPU). If it gets worse, then the answer is probably ... if so, try then moving that capacitor between ground and Vcc (pins 20 and 40


is unfortunately completely over my head (as I mentioned, my knowledge of circuit boards and the shorthand lingo is minimal). Add to the fact that I'm in a small town in Canada where we don't have RadioShack or any place that readily sells capacitors anymore (which completely sucks) - I had to get the 2200uF from some backdoor alley place (quite literally) in a city 40 minutes away. If you'd care to elaborate on how I can try this test, I'd be willing to give it a shot.


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 2:39 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7392
Location: Seattle
What electronic parts do you have handy? I might be able to suggest a workaround.


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 4:24 pm 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
Not very many. I have the original capacitor out of the NES that was removed to make room for the replacement and the unusable axial one. Both are 2200 uF/25 volt. Tons of assorted cables and so on, but, it's slim pickens beyond that.


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 8:30 pm 
Offline

Joined: Mon Sep 27, 2004 2:57 pm
Posts: 1249
This is kind of a doofusy question and it might've been answered already, but have you tried plugging in a different game console (like a SNES) and seeing if the lines are still there?


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 11:11 pm 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
Yes, I tried the RF switch on the SNES and the lines were not there. It's definitely a problem indicative with the NES itself.


Top
 Profile  
 
PostPosted: Sat Oct 11, 2014 11:32 pm 
Offline
Formerly 65024U

Joined: Sat Mar 27, 2010 12:57 pm
Posts: 2262
Bad caps is the problem with the console, the same as it was 10000 posts ago on this topic.


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 1:43 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7392
Location: Seattle
So. Picture shows a varying frequncy, so is some kind of FM. Frequency seems to vary from 1280kHz to 1240kHz, by counting pixels and comparing to the known pixel clock. Assuming output has been (incorrectly) deinterlaced by the television, two subsequent frames show almost identical timing and phase, except in the middle of the frame where the boxer's gloves are. So whatever signal's been modulated, it's basically only got multiples of 60Hz in it. (Specifically ... looks like 120 Hz plus some higher even multiple for the asymmetry) If it were a beat pattern against mains or NTSC frequencies, it would shift by a half scanline or 70% of a scanline every vblank—too small to see in this picture, I think.

Question: just how stable are these waves? do they move while the NES is on? How fast?

Assuming it is bad capacitors, and having already replaced the big on on the input stage to the 7805, you could try adding the one of those extra capacitors you have (the axial one should be easy, I'd hope) in parallel to one of the existing capacitors (Naively I'd put it right next to the PPU)


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 8:59 am 
Offline

Joined: Sun Sep 19, 2004 11:12 pm
Posts: 20413
Location: NE Indiana, USA (NTSC)
They move down slowly while the NES is on, as if it were beating between 60.1 Hz (NES and Super NES vertical frequency) and 60 Hz (fluorescent bulbs or PSUs) or 59.94 Hz (vertical frequency of other video equipment). I'll have to count the beats more precisely to see which.

EDIT: I just measured it, and it takes about 20 seconds for the wiggles to progress all the way down the screen and wrap around twice. This gives 10 seconds per loop, as if it were beating between 60 and 60.1 Hz.


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 9:04 am 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
lidnariq wrote:
Question: just how stable are these waves? do they move while the NES is on? How fast?


See for yourself... http://youtu.be/dlMoNiIjrX4

lidnariq wrote:
Assuming it is bad capacitors, and having already replaced the big on on the input stage to the 7805, you could try adding the one of those extra capacitors you have (the axial one should be easy, I'd hope) in parallel to one of the existing capacitors (Naively I'd put it right next to the PPU)


So, you're saying literally touch the axial capacitor to the circuit board while it's running? I hope that's not dangerous. :P

3gengames wrote:
Bad caps is the problem with the console, the same as it was 10000 posts ago on this topic.


Forgive me for being blunt, but, this comment doesn't help the problem at all, so, if you have nothing constructive to add, perhaps you should ignore this thread. As was mentioned earlier, the main 2200 cap has already been replaced with no effect. If you know another capacitor that could potentially be the culprit, suggest which one it is. There is very little information available on this problem online and most people who have encountered it on other boards that I've read either don't report the progress of any solutions or just forget about it. Since this seems to be a recurring problem with many systems, I would hope by the end of this, we'll have a working solution that other people can look to to get their systems operating correctly.


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 9:18 am 
Offline

Joined: Sun Sep 19, 2004 11:12 pm
Posts: 20413
Location: NE Indiana, USA (NTSC)
I put in an NES cartridge that shows a light gray test screen and did some things while the power was on:

While viewing through composite, the exact pattern of wiggles changes noticeably when I unplug the cable to the RF switch and changes back when I replug the cable.

While viewing through RF, the pattern changes slightly when I unplug the yellow cable and changes back when I replug the yellow cable.


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 10:52 am 
Offline
Formerly 65024U

Joined: Sat Mar 27, 2010 12:57 pm
Posts: 2262
To be blunt, filling the forum with tons of posts that aren't relevant because they don't help us get farther either is why my comment exists. We told you what the problem is, confirm it when you can, otherwise why fill itwith how many combinations and whatever obviously will work and not, we already know that. My comment is as useful as all others after we posted what the problem is.


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 11:27 am 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
3gengames wrote:
We told you what the problem is, confirm it when you can


Did I not do that by informing everyone that replacing the main capacitor did not help matters?

3gengames wrote:
Otherwise why fill it with how many combinations and whatever obviously will work and not, we already know that.


I'm sorry, but... what?

3gengames wrote:
My comment is as useful as all others after we posted what the problem is.


Fine, you say it's a capacitor problem? Which one? There's a few of them on the board and we already know it's not the 2200 one. So, where to now?


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 72 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC - 7 hours


Who is online

Users browsing this forum: Yahoo [Bot] and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group