Problem with NESRGB, Help appreciated

Hi guys,

I have some issue with a NESRGB I'm trying to install on an old french NES..

After letting my Nes turned off for a while, if I go back to it, it will have no image and a long buzzing sound. It turns out this buzzing sound is actually the first note of my game intro.

If I let it run, I will have the second note, very slowly , then the third , then some image, then everything will go faster and faster, the image cleaner and cleaner, to a point where the game will actually work PERFECTLY. Image and sound (the all process is probably about 10 minutes)

It's so strange I ve recorded part of the process to show you what I mean.
Vidéo 1
Vidéo 2

A few things to note:
- I immediately thought it was a cap issue so I've changed the 3 main ones in the AV box. Haven't changed anything else yet.
- I have a stable 5V on the NESRGB, the PPU and the CPU
- if I put the PPU back to the NES board, everything works perfectly fine.
- I wanted to make sure using the original AV Output and power was not the issue so I'm now using the RGB mini din and the power board.
- once I got any game working it will continue to work . I can rest, power off, change game and all will work. But if I let some time pass with the NES turned off (over an hour) I will get back to no image no sound and the long process described above.

I m very puzzled . As you can see the board can work but I just don't understand why the system will behave like this. Any idea ?

Thanks a lot,

Romi

 

Have you checked the voltage on the voltage regulator? Tried a different power adapter?

 

Hi,

Yes, I have a stable 5v on the nesrgb board, the PPU and the CPU. I've tried with 2 different official Nes adapters (that I'm using on a daily basis with all my NES and SNES)

 

That looks like it might be a sync issue of some sort to me. Could you give some more info about the install? How the NESRGB is wired, what type of cables/method are you using to connect to the TV, how do you have jumpers on the board set, etc. The more info the better. =)

Check if the NESRGB itself is working properly by trying something like the s-video or composite output of the NESRGB. (You don't have to install a jack on the console, just wire one to it so you can plug it in.)

Some pictures of the mod install itself may help as well.

Power is probably not the issue here. You can change all the caps just to be safe though.

 

Hey,

I was thinking about a sync issue too but the facts that board ends up working perfectly fine makes it doubtful. Also it would explain the poor image but not the slow sound...

Right now I'm using V for Sync with Tim's provided mini din and Scart Cable.

Can you tell me more about trying the composite . What pin is it on the NESRGB ? V ? Thanks,

Romain

 

Just wire a composite jack to the NESRGB. Just use any random jack and hook up the signal + ground.

It's V, or PPUV for the PPU composite.

Info about your jumper setup may help tremendously. Also what is the scart cable going into before it hits the TV?

How is the audio hooked up as well?

 

Do you happen to have a photo of the board? Are you using the voltage regulator board that was included with the NESRGB (or at least it was at some point)?

Also, have you tried contacting Tim Worthington about the issue? He'd probably have the best advice since it sounds like there is perhaps a defective component on the NESRGB setup itself since the system works fine with that taken out of the equation.

 

Check the tantalum caps on the NESRGB maybe?

I've had one of those fail on the NESRGB's component add on board.

Was a pain to find. Had to have it plugged up to the tv and poke around with my oscilloscope. Damn thing only failed under load.

It taking 10 minutes or so to work might point to a component not working at cold, but working once the board/system warms up a bit.

 

hi guys thanks for all th reply
@Yoshiknuckles
Here's a pic of my board (Audio A & B and External regulator are coming through Dupont pins at the bottom of the board) :


- Jumper J4 and J7 are soldered. I will try the composite out tonight (I'm in France)
- Il also think the problem comes from a a component not working at cold. So a cap looks definitely like a possibility. I don't have an oscilloscope, only a multimeter. Any advice to test the caps would be greatly appreciated.
- I did not use audio at first then solder the audio out of the board to pin 1 & 2 of the minidin (same results but with sound)


@Xzx123 see the pic above. I have contacted Tim, but I'm waiting for a reply. He's a very busy man and I don't want to harass me. And I know there are a lot of smart people in the community.
I was using the NES regulator, then changed to the external one provided by Tim with the same results.

Thanls again,

Romain

 

Some of those solder points look a bit iffy to me, especially the black wires at GND and 3.

 

Agreed, it also looks like perhaps the green wire is touching the bottom side male header pin.

Use a multimeter and make sure there is no continuity.

 

@AtomizerZero @citrus3000psi thanks for checking. My solder skills are definitely not world class but I have checked the continuity and voltages many times. Also the top red and black wires are just here to power the minidin . The board Itself is powered with DuPont pins at the bottom of the board.

Also the fact that the board does eventually work (without me playing with the wires) makes me think it's probably not a wire / solder issue. I totally could be wrong though but I really checked continuity and voltage many times.

Thanks again

Romi

 

Could you show some pics of the underside of the nesrgb and wherever else you have soldered to?

 

Ok so yesterday, I was so frustrated with this thing that I decided to remove everything and use another NESRGB board I was keeping for another console. and... exact same issue :-( So it seems the problem is my console after all (which is incredibly strange considering it was working with the PPU in its original place).

So now I'm wondering, what kind of component could cause my console to start bad (highly distorted image and music going very slowly) then run perfectly when hot... and go bad again when it's getting colder ? I tend to think that a bad PPU or CPU wouldn't do that right? (in my experience they either work or don't work) Maybe the Vram chips ? I have changed all the Electrolytic capacitors.

So yeah, any advice on tests I could run would be greatly appreciated.

 

If if works fine without the mod, but doesn't work fine with it, then it's either power related or its how your installing it. personally, I think you should remove the mod and all cables, and then follow the guide again while installing it. also, at each major step, test your connections with a multimeter and double check to make sure your soldering to the right places.

Actually.... first thing I want you to try before all that is solder a different pallette to ground (do 1 to Gnd instead of 3) then test it.

 

@AtomizerZero This one is a totally different board on the same console so I had to desolder everthing (except on the minidin side but I would be surprised if it was causing this kind os issues.

I will try a a different pallette

Thanks,

Romi

 

@Romi I understand that, but it doesn't hurt to recheck. also, I have heard of similar issues with someone who didn't solder the ppu socket and pins properly. one of the traces to the ppu wasnt linked, so he got no picture but very slow sound.

 

have you replaced the reset cap? ive had that cause odd issues with an everdrive, maybe causing this issue with the RGB? just a guess since it sounds like its works after warming up

 

@AtomizerZero Very interesting, I will check again. Tim just replied to me advising me to check the clock circuit (connecting to PPU pin 18) as It controls the speed of the CPU/PPU.

 

I've also had experienced with nes high def install where one of the PPU pins was barely making contact on and off with the socket. When you check continuity; the meter would push the pin and everything looked good. Pulling the PPU out, cleaning all the pins very good and then pushing the pins inwards/outwards to give a tighter fit fixed the problem.