Nintendo Super System NSS Not Booting UP

[Mr.Heef]

Hey everyone. Apologies in advance, as I'm very very new to working with arcade units.

I just picked up a Nintendo super system and it powers on only to a black screen with the words "Just a Moment" on it.

I found DogP's site with some general troubleshooting information and it looks like maybe this is related to the BIOS it currently has. I found a ROM of a BIOS file that displayed the text the same way as it does on my machine.

https://romhustler.org/rom/mame/nintend ... ystem-bios

Any advice or info at all would be greatly appreciated, thanks.

[brizzo]

Late to reply, just saw this post.

When the NSS displays "Just a Moment", during this period the Z80 is executing bios code that checks and verifies the cartridges that are installed. Each cartridge has an "instruction rom" which is what provides the game title for the game selection screen, along with the on screen instructions.

If the NSS is stuck on this screen, here is a list of reasons:

• Check voltage at jamma edge connector, verify 5v is around 5.05 volts

• Install only 1 game cartridge, try swapping if you have more than 1

• If swapping game carts or reducing count works, then re-seat chips on cartridges

• There are 3 versions of the bios, v1 and v2 are not compatible with the larger carts, but works with the smaller super mario world and tennis cart type

• Worst case, which I have seen once during a repair, the 74' logic chip used to select which cart slot is active is faulty