Great Hierophant wrote:A basic question I have is that with the tantalum route, you do not need to lift the PPU Video Output pin to eliminate jailbars? That is a good thing if you do not have to do that.
I have not tried that yet. My pin is still connected in my test unit.
The 560pF seems to have no effect on the jailbars, but a finer grid pattern appears without it. lidnariq pointed out that this artifact is chroma-into-luma bleed. I would recommend using the 560pF. It dulls the colors slightly but does not make the image any more blurry. I also brought a typical cheap/thin yellow RCA cable with me today but I forgot to try it. I want to see if the ferrite bead makes a difference with that cable. I would not recommend making any change to a real AV famicom, Nintendo seems to have gotten it right with this model.
I have been having somewhat of a disaster of a night, not going too well. I finished wiring up the soccer cart into 240p Test Suite. It wasn't too bad, I had to use some copper foil to get at PPU /WR and CPU R/W but that went okay. I got home and went to program my W29EE512P-70 and found that my fresh Chinese PLCC-32 to DIP adapter had 2 (TWO) opens in it... Fixed that and programmed the chip. I put the cart in my Hi-Def NES and KABOOM, something blew up! No power with or without the cart in there now... Another project for another day. Hopefully fixable.
So I sat down with the cart, looked and probed for mistakes, shorts, etc, found nothing
. I bravely threw it into another NES, and it was okay, no explosions... Not sure what happened with the hi-def NES, no visible damage anywhere.
The 240p Test Suite PRG runs great. I did end up going with the BN-ROM approach, I used a 74LS163 that I had, which is compatible in this case. However, the CHR-RAM isn't working quite right.
The same tiles remain glitched when resetting, jiggling, etc. I used a UM6164AK-25 for the CHR-RAM. I tried swapping from the 'H' jumper to the 'V' jumper, that introduced additional problems, went back to H. I also tried swapping /OE and /CE on the RAM (PPU +A13 and PPU /RD), that made big problems, went back the way it was. I have a whole stack of these 6164s, I tried a different one and it didn't make a difference. Could -25 be too slow? Hmm... Anyway, it is good enough to use it for video testing purposes, just sort of a shame it is glitchy.