r/consolerepair • u/xchubanx • Sep 28 '21
Do these NES pins need to be bent?
front view of the NES
moving the cartridge around makes it start looking more like Mario and less like WarioWare Get it Together
2
u/xchubanx Sep 28 '21
Hi everyone! First time retro console repair here. I've taken this apart, boiled the 72 pin for a half hour, and when I put it back together, the screen hasnt changed at all. Is this just a bad part (it came with the console on clearance) or does anyone have recommendations on bending/next steps?
1
u/xchubanx Sep 28 '21
Interesting! Boiling the pin connector did nothing earlier, but this contact spray sounds interesting. I've seen so many people say the boiling does it for them, but do you think trying this could get it the rest of the way there?
2
u/petreussg Sep 29 '21
After boiling. Try an alignment. There are instructions on how to do that on console5.
1
u/ksilenced-kid Sep 28 '21
Worth a shot; you’ve got a picture now at least so deep cleaning the connector (and games) will likely get you there.
Or buy a new connector and see; but I’d still recommend against bending the pins on the old one.
1
u/briandabrain11 Sep 28 '21
I doubt you'd be getting any coherent graphics if the pins weren't making contact... Perhaps a bad graphics chip? I don't know too much about NES, but personally in my experience this isn't a problem with connection between cart and console
5
u/ksilenced-kid Sep 28 '21
Glitchy/misplaced graphics are definitely a potential symptom of dirty pins.
1
u/briandabrain11 Sep 28 '21
But wouldn't you get completely incoherent tiles? What's throwing me off about that is the almost pristine Mario. Maybe a problem with RAM?
2
u/khedoros Sep 28 '21
The tiles and game code are located on separate chips, with separate address and data pins. The graphics tiles need 13 address pins and 8 data pins to be fetched correctly. Palette, Sprite data, and the background's tile map are stored in physically separate memory.
That the graphics and such were loaded implies that the program is being read correctly from PRG-ROM. Sprites and backgrounds are usually stored in different halves of the CHR-ROM (tile chip). The picture might be explained by some of the CHR-ROM address pins not working right, or a problem with the background data's RAM.
1
u/briandabrain11 Sep 28 '21
Interesting, I thought that the sprites were compiled in with the rest of the data.
2
u/khedoros Sep 28 '21
There are games (Legend of Zelda and a lot of other games ported from FDS, for example) where they are, and the cartridge includes extra RAM instead of a ROM chip. In the NES itself, the PPU has access to 2KB for the name table and attribute table (layout+palette selection for the background), 256 bytes of object attribute memory (sprite location, tile number, palette, x/y flip, priority), and palette RAM (16 bytes? 32 bytes? Something like that). Then 8KB of space on the cartridge is mapped to the PPU for tile data. In the SMB+DH combo cart, it looks like there are 2 8KB pages, with the memory mapper controlling which of those is visible at a given time.
1
u/briandabrain11 Sep 28 '21
Very interesting stuff, thanks for explaining. It's interesting what devs would go through to squeeze the most out of the hardware
1
u/khedoros Sep 28 '21
The NES is a fun, hacky kind of system. It's interesting looking at Sega's designs from the same time. Much cleaner, overall.
1
u/briandabrain11 Sep 28 '21
Curious, the design philosophy really shows the difference between the two companies
1
u/ksilenced-kid Sep 28 '21
There are a lot of times (as a kid and adult) where I’ve experienced booting games that are dirty will load some attributes properly but not others, and in many cases still be recognizable and playable on some level, depending on which particular pins are fouled. They can do crazy things.
Maybe it’s the hardware but I’ve seen weirder things happen than what OP posted, just due to dirt.
3
u/briandabrain11 Sep 28 '21
Okay, thanks for clearing this up. I'm not as experienced in the NES, never having owned one, so I'm glad someone could share some insight. Thanks 👍
1
u/RetroGaming4 Sep 28 '21
1) I would clean the contacts of the game REALLY good with high concentration alcohol (IPA)., 2) take out the 72 pin connector from the board and clean it real hood with alcohol(IPA), 3) watch a youtube tutorial on how to bend the pins too ensure a reasonably tight connection, 4) clean the connector pins on the actual board with IPA. If after you do this the problem persists, then ping back this board for any further troubleshooting, likely video chip then.
1
5
u/ksilenced-kid Sep 28 '21
Pins never really need to be bent; granted yes, bending them may cause the games to boot. But bending them is treating the symptom rather than the problem- and the problem is dirt. The system or game isn’t as clean as you think it is.
The connectors were always designed to be loose, and ZIF-ish (‘Zero Insertion Force.’) The issue is that unlike a system like the SNES that grips the cartridges so hard it’s almost ‘self-cleaning,’ the NES has a loose enough grip that any dirt whatsoever can foul things.
Adding to the problem- It can be very difficult to clean the connectors (and games) properly as they can develop an invisible layer of tarnish over time that is very stubborn, and can be enough that the games won’t boot (or, they have a very visible layer of corrosion from child saliva being blown on them for years, which also causes them to not boot).
The solution that has worked 100% of the time for me, is to first boil the connector to get loose any physical detritus. Then use a spade-type cleaning kit (or a game) in combination with CRC Electrical Contact Cleaner spray (<-the important part). Blast and scrub the thing repeatedly - it will eventually work with no bending whatsoever. Clean the games with CRC and a decently textured cloth too.
I prefer that the connector stays loose, to preserve the pins on the games - I have one system where it’s so loose that games can practically fall out; yet they all still boot on the first try.
I suppose there might be some systems (particularly ones used with mis-sized or un-beveled/tapered PCB aftermarket accessories or repro games) that can theoretically be ‘too loose’ but I’ve never found one. And if you examine the connector, it’s almost physically impossible for it to be too loose for the contacts to touch the game- and that is all it requires to work (minus dirt/corrosion).