It is currently Sun Jun 24, 2018 3:39 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 69 posts ]  Go to page Previous  1, 2, 3, 4, 5
Author Message
PostPosted: Sun Oct 12, 2014 11:32 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7233
Location: Seattle
Bridger wrote:
So, you're saying literally touch the axial capacitor to the circuit board while it's running? I hope that's not dangerous. :P
No, not while it's running. Just clip it in and see how the NES runs while you're going. Ideal places to add it would include "across the PPU" or "across the PPU's bypass capacitor". Here's a picture:
Attachment:
ppu_power_ground_marked.jpg
ppu_power_ground_marked.jpg [ 18.97 KiB | Viewed 1806 times ]

tepples wrote:
beating between 60 and 60.1 Hz.
Ok, that's pretty clearly power supply crappiness.


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 11:43 am 
Offline

Joined: Sun Aug 10, 2014 6:07 pm
Posts: 21
Well there's more than one capacitor in there.

If any of them are doing a shitty job of filtering power (that's their job, and they retire at age 15) then that will be making it through to the video signal. Nobody replaces one capacitor and calls it quits. I wouldn't really expect replacing one capacitor would make a difference to be honest. Would you replace one spark plug in your car? Btw I think if there's any capacitors I've NOT replaced, it's the big ones. They seem to hang in there longer and I don't usually have them on hand. All the little ones have to go.

I think that's what 3gen is talking about here. Until you replace them all there's not much point in looking deeper.

edit: This assumes your power supply is putting out nice, clean power. New capacitors won't fix a terrible power supply.


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 12:12 pm 
Offline

Joined: Sun Sep 28, 2014 10:25 am
Posts: 23
Fair enough. As I've mentioned many times in this thread, I'm relatively new at this level of repair work. I've replaced the pin-connectors before, that's it. As far as capacitors and modulators and circuit boards and so on go, I'm very inexperienced beyond what I've picked up as I've investigated this problem. Since it was suggested that the main 2200 cap tends to be the culprit, I started there.

I'll search around online and see if I can find a pack that has all the new caps in it for an NES. Being in Canada, it seems that you can only get stuff like this online, anyway. ;)

Quote:
Ok, that's pretty clearly power supply crappiness.


I think we can safely rule out the power adapter itself because using a Genesis one didn't change anything... unless using a bad power adapter can damage the NES?


Top
 Profile  
 
PostPosted: Sun Oct 12, 2014 12:54 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7233
Location: Seattle
Nah, switching between different unregulated power supplies won't change things much.

An obvious workaround (although it's suboptimal for other reasons) is to use a newer-style switching DC power supply of 7-10V or so. They won't emit any 120Hz (from the NES's AC transformer and full-wave rectifier) and so should make the waves invisible (because the switching frequency will be in range of 10s to 100s of kilohertz)


Top
 Profile  
 
PostPosted: Mon Mar 12, 2018 12:25 pm 
Offline

Joined: Wed Jul 19, 2017 10:23 am
Posts: 78
I had an NES that only gave a grey screen and in the process of trouble shooting I decided to just recap the RF module. I used the right type and everything, got them from Game-Tech website. Before I did the recap I had a solid grey screen but afterward I now see these waves as pictured and discussed in this thread. Could it be a bad capacitor? This was my first soldering job so maybe I did not have strong connections or cross connections? What could I try to fix this issue given that I actually created it as explained?


Top
 Profile  
 
PostPosted: Mon Mar 12, 2018 1:49 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7233
Location: Seattle
Check for cold solder joints—they have a higher resistance than well-flowed ones. If you're using lead-free solder they're easier to create.


Top
 Profile  
 
PostPosted: Tue Mar 13, 2018 5:58 am 
Offline

Joined: Wed Jul 19, 2017 10:23 am
Posts: 78
To clarify... lead-free solder is easy to get well-flowed solder joints? So you recommend that I use lead-free?


Top
 Profile  
 
PostPosted: Tue Mar 13, 2018 10:06 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7233
Location: Seattle
Er, no. It's easier to create a cold solder joint when using lead-free solder.

Not dramatically so, though.


Top
 Profile  
 
PostPosted: Tue Apr 10, 2018 8:00 pm 
Offline

Joined: Sat Jun 10, 2017 8:44 am
Posts: 16
Have you tried replacing the voltage regulator? I had the same issue with a Super Nintendo. I bought a new, high rated 2 amp 7805 from console5.com and when I soldered it in place it made the video crystal clear. I also recapped it first, but the problem wasn't solved until I had put a new voltage regulator after putting all new caps.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 69 posts ]  Go to page Previous  1, 2, 3, 4, 5

All times are UTC - 7 hours


Who is online

Users browsing this forum: Majestic-12 [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