NES2 vertical lines

[emuman100]

How can one get rid of these damn things?

The original used the same PPU as the NES2, and famiclones thast have lines use a cloned PPU, but they probably don't apply here. The original NES and NES2 use the same PPU, but the NES2 has the vertical lines? I can only think of noise being the possible cause. The original NES had two .01uF caps and a 10uF 35V electrolytic cap in parallel with the filtered DC output after the large filter capacitor and ground. This was omitted on the NES2. I purcased schematics from MAT electronics, and despite how incomplete they are, they are a little helpfull, but they don't show the 5V bypass capacitors. Could a noisy 5V line as well as noisy input be the cause of the lines? 5V bypass capacitors should be connected to every Vcc input on the PPU to ground, being as close as possible to the PPU to reduce the logic noise?

Has anyone ever thought of this or play around with this idea?

Jonathan

[phreak97]

i thought the original nes had them too...

[Bostich]

I always thought it was because of a bad RF modulator.  I took mine in to a Nintendo service center (this was in 1994) and they fixed the vertical line problem.  I'm not 100% sure what was replaced, but I'm guessing it was the RF modulator.  Unfortunately, I don't have that system any more so I can't open it up to take a look.

I have heard that people who have done the A/V mod for the NES2 were able to eliminate the vertical lines, but I have not done the mod myself.  I've never seen the problem on front loading system.

[viletim!]

I had a nes 2 long ago. I modified it to output composite video like the original nes and the 'vertical lines' were still visible, perhaps even worse than they were through the RF output (the modulator may have had a sort of low pass filter effect). I eventualy broke that console and threw it out.

I'm not sure what's causing the lines but here's what I can think of:
- add more decoupling caps to the power supply rails near the PPU
- swap the PPU with one from a normal nes (are they REALLY the same?)
- compare the video output circuit of the nes and nes 2. My nes circuit diagram shows some caps in parallel with the video signal, presumably to reduce the high frequency content. Maybe you could try to connect the output circuit of a nes (or build one from the circuit diagram) to the PPU video output of the nes 2.

[dhau]

Did anyone at all successfuly replaced NES2 PPU with one from toaster NES? I tried, and I'm good with my soldering/desoldering (numerous successful PS2/GC/Xbox mods), and it didn't work at all...

[DarthCloud]

Probleme was solved at nesdev just read the whole threats:

http://nesdev.parodius.com/bbs/viewtopic.php?t=601