Naomi GD Rom. Error 22. New Dimm, no good. What's this part?

[OldFoo]

First, let me preface this in that I am a noob at the Naomi stuff. I'm trying to fix an import machine here, and not having much luck.



My biggest issue is this: Naomi GD-Rom system works fine for years. Then, I got an error 22, so I assumed (after cable swaps, etc) that I needed a new dimm board. However, that didn't work at all.



Looking at other setups online, I noticed that they are one less part than mine does. Mine has, for all intents and purposes, an 'extender' - the Dimm board fits fine in the machine without it, so I'm not sure why it is there, what it is, or if that part is my issue.



Without further ado, the pic:







The top pic is a 'side view' - the dimm goes in the top of that, and the whole thing goes into the Naomi. It looks like it is just some sort of 'pass through' extender.



Note - if the dimm is not plugged in, I get a simple Error 01 game not recognized error.



So, my questions:



1. what is this called?

2. do I need it?

3. could it be the Error 22 issue?

4. if not, what else could be the problem? I get the 22 even if the GD Rom isn't plugged into the dimm.



Thank you for any help you can give!

[OldFoo]

The additional board is a Naomi Communications board, used to link multiple Naomi machines together (for multiplayer games supporting multiple cabs). If you are not linking cabs, just remove the communications PCB, and insert the DIMM directly in the Naomi.



Error 22 can indicate a failure of the DIMM board. First try checking your PSU voltages for correct levels. If that does not help, open up the DIMM board, reseat the DIMMs that are inside and try again.

[OldFoo]

Excellent, thanks for that info!



That being said, both dimm boards have been opened, reseated, etc etc, to no avail.



Can you explain in greater detail what you mean by "First try checking your PSU voltages for correct levels"? Again, thank you so much for your help, you are a lifesaver here.

[OldFoo]

Also, try changing the USB cable. This error drove me nuts one time, working one day, the next day not. Since the usual didn't work I started trying everything and changing the cable worked. I'm not sure why, but when the Dimm module is inserted and the Naomi doesn't detect the I/O board, this error occurs even though it's not related. :smt102



Of course, this might also mean that the I/O board may be malfunctioning.