SNAC Mega Drive/Genesis issue

[Meringues]

I wonder if anyone would be able to help me out here, I have a USB 3.0 style Snac board and have the analog v6.1 io board.

As far as I’m aware I have all the jumpers set correctly and I have pin 10 on connector P7, I’m using Sonic the Hedgehog to test.

The problem I’m having is when I push Right Sonic jumps to the right, when I push B Sonic also jumps to the right. If I hold the B button down he runs right, all other buttons function as they should, I can’t find any solder bridges so I’m at a loss, any suggestions?

[PikWik]

hey there!
i know these types of issues can be maddening. especially when everything "looks" just fine

can you replicate the issue with 2 different genesis controllers on the same SNAC?
do these same controllers work on a genesis/computer without using the SNAC??

if so, and the issue on the SNAC follows 2 different controllers, then it is an issue with the board.
you could also test for continuity between the SNAC's input dsub and the corresponding solder pins if you have a multi-meter.
(but im leaning towards the controller's wires getting exposed/crossed somewhere in the cable)

[Meringues]

I’ve replicated the issue with 4 original controllers and 2 third party controllers, the snac board works perfect with pc engine and SNES controllers, I’ve tested with a multimeter and it seems fine, I’m completely lost

[OriginalXOR]

Have you closed the Jumper of the SNAC itself when using Megadrive/Genesis controllers?

20210207_110026.jpg (94.64 KiB) Viewed 3332 times

Nat from MisterFPGA.co.uk has a great guide for this and can be found here: https://misterfpga.co.uk/sega-genesis-c ... nac-setup/

A worthwhile read, if only to check the most obvious bits, and if only to check you haven't missed something silly (like I did when I first used a SNAC Adapter).

[Meringues]

Yeah I actually checked there, both jumpers on the snac and MiSTer are set correctly, I should also add I have two Megadrive pad adapters from different sources, both the same problem, I’m ready to give up

[PikWik]

hmmm,
if the SNAC works with a SNES and PCengine adapter, then im thinking its not the SNAC board, but an issue with the sega adapter for the SNAC, or IO board incompatibility issue.
but then again, im doubting its the adapter because you have 2 different sega adapters with the same error

if you have a spare SD card, perhaps trying a clean start/fresh install may fix things?
and where did you buy the 6.1 IO board? was it from a reputable seller??

misteraddons has a note about using SNAC - https://misteraddons.com/products/seria ... erter-snac

"NOTE: ONLY COMPATIBLE WITH IO BOARD 6.1 / IO DIGITAL 1.2 AND NEWER. IO BOARD MUST HAVE PIN 10 ON CONNECTOR P7 TO USE GENESIS CONTROLLERS. NOT ALL SELLERS INSTALL ALL PINS ON P7. MINE DO INCLUDE ALL REQUIRED PINS."

which very well could be whats going on here.
i understand buying a new IO board to test this may be overkill, but could be a possible solution

[Meringues]

Update: so although my io board looked fine I decided to remove all the pins and re solder new ones myself and everything is now working perfect, either a dry solder joint or a bridge somewhere