NES with odd glitches after connector replacement

[cynicalhat]

Hi, I've trolled this forum for a while now, however this is my first time posting.

I have this Original formfactor NES that i have replaced the 72-pin connector on. I have also polished the connector on the motherboard so that you can see the light reflecting off it from space. Cleaned the terminals on the connector with electronic cleaner, alcohol and other things with a toothbrush to really get in the connectors tight area. I have also disabled the CIC chip by removing leg 4 on the chip. I have also tried another 72 pin connector to eliminate this as the culprit and i get the same issue.

Now the NES powers up and games work on the first try every time. The problems that persists are:

Mike Tysons Punch Out!
On the title screen before you press start you can see one of the sprites that make up the glove that punches through the title when you do press start. Portions of the opponents sprites get their colors all wrong.

The Legend of Zelda 1
On the menu screen the item sprites tend to flicker alot. Also when you meet any old man between 2 fire sprites, It tends to flicker alot as well.

These are just 2 examples. The thing is, it is the same issue every time you insert these games. There is never a gameplay problem and these problems dont exist on another NES that I've used the same maintenance techniques to. Also the games have been cleaned and polished as well. I am hoping that someone else has had this issue and solved, or if there is something I may have missed. Thanks in advance. I can provide pictures if needed.

[FABombjoy]

Replacement pins can be frustrating, unfortunately. I haven't really had any good luck with them.

One (not particularly documented) issue that I've seen is that the cart connector & carrier alignment can have an impact on the quality of connection. Before tightening the screws that hold the carrier & connector together (and carrier to the case), insert a cartridge fully & click it down, THEN tighten the screws.

This helps to set the alignment betwen the cart & pin connector, and I've had it make all the difference in the world on systems that never could quite shake the character ROM glitches. I'm not sure if it'll help in this case, but it's worth a shot.

I've also had pins on the 3rd party connectors back right out of the plastic holder. Might want to double-check that they're all inserted snugly.

Some have also noted better results with 3rd party pin connectors by NOT latching the cartridge down, just leaving it up and playing that way.

[cynicalhat]

i tried it with an oem connector and a replacement (the replacement now lives in another perfectly working NES) ive tried them in both NES's and the other NES works like a dream, this one has the same issue regardless of the connector. all the pins do stay in the connector as ive tested with the top off and on. its worth a shot on the tray though.

[cynicalhat]

screwing down the tray while having a game in it didnt fix the corruption. i tried it a few different ways. pressing the game fully down, letting it sit in the down position and having it in the up position. mike tyson still looks like a seagull took a green turd on his shoulder.

[FABombjoy]

Poor, poor Mike!

If the glitches are consistent and unaffected by mechanical prodding, it's probably time for board troubleshooting. Do any of the chips get noticibly warmer than others while it's running? Something like one of the SRAMs, specifically U4 as I believe it's used by the PPU. I would also check VCC for voltage/ripple and scope out in the PPU neighboorhood lines to check for something wrong on the A/D lines.

Component troubleshooting resources for the NES seems to be few & far between. I've had more NESes than I can remember over the years and they all just needed a good cleaning.

[cynicalhat]

thank you for your help so far.

i got some temp readings all in farenheight (sp)
ambient room temp 65
cpu 109
ppu 86
u2 79
u4 (VRAM)73.5
cic 78 (weird since its disabled)
u1 (VRAM) 70
i let the system warm up playing the mike tysons demo for 10 min and played for another 5 in a quick game of ninja turtles

the massive color distorting flicker (more than a typical NES) seems to happen when there are a few moving sprites on the same horizontal plane. also of note, the game seems to have more noticeable slowdown issues but that could be my perception.

[FABombjoy]

Provided that is passes a visual inspection for shorts, breaks, etc., I would think it's something PPU related. I'm not sure that remote diagnosis can get you much further

[Gameguy]

Could be the video encoder is dying(which is most likely what happened to one of my systems), or you screwed something up when you were messing around with it.

[cynicalhat]

well i looked it over and i didnt see any breaks other than the one i made for the cic chip, ill take a closer look at the video encoder and whip out a multimeter.

[SithWarrior]

One (not particularly documented) issue that I've seen is that the cart connector & carrier alignment can have an impact on the quality of connection. Before tightening the screws that hold the carrier & connector together (and carrier to the case), insert a cartridge fully & click it down, THEN tighten the screws..

Thank you very much for the tip FABombjoy, my NES has no more problems reading games anymore thanks.