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[Repair Log] Naomi 2, take 2

Continuing the saga... Someone in another thread suggested replacing the buffer chip on the NetDIMM.

So, couple of days later, I got some replacement chips, and voila:

IMG_20221117_234213652_HDR.jpg



The original is the one on my finger. The replacement is the Philips part. I guess I'm getting better at SMD soldering. This one involved no curse words and took 10 minutes, a record :thumbsup:

However, it still causes an error 22 ?( Someone mentioned that the DIMM BIOS could be damaged as well. Which chip is that? IC11 at the top of the daughterboard?

I managed to get ahold of a cheap(ish) game cart to make sure that the problem is not the Naomi itself, but I'll probably be getting it only by the beginning of December...
 
Got the game cart in the mail. It's a Virtua Tennis cart, and was incredibly filthy with soot/cigarette smoke(?). After cleaning it thorougly (including a ton of contact cleaner on the connectors), I can at least know now that my Naomi 2 is working fine. Fires up okay every time with the cart.

So, the problem is indeed still with the DIMM. Ordered replacement TSOP-48 NOR chips for the BIOS (Macronix MX29LV160DTTI-70G), as apparently I can use one of the two available positions on the PCB to solder either a 56-pin (which mine has) or a 48-pin (the Macronix one). Should arrive in a couple of weeks.
 
doccaz said:
it still causes an error 22 ?( Someone mentioned that the DIMM BIOS could be damaged as well. Which chip is that? IC11 at the top of the daughterboard?
Click to expand...
Replying to myself: the BIOS chip in the DIMM is IC14/IC36 (according to the chip used as mentioned above), on the other side of the board.
 
doccaz said:
Wasn't there a way to enable the onboard serial port for debugging?
Click to expand...
Yes, there's two jumpers that need to be moved on the NetDIMM board and then just use a regular null-modem serial cable and you can watch the OS on the NetDIMM boot up. I can't find a reference right now but IIRC they're on the lower board.
 
Alright, got the replacement Macronix MX29LV160DTTI-70G flash chip and the proper TSOP-48 adapter (albeit I got the terrible solder version instead of the ZIF one... gotta read these AliExpress ads more carefully ?(). Soldered the darn thing to the adapter, had to fiddle with it at least half a dozen times to make sure all the pins were soldered and making contact properly.

Got the BIOS image from https://archive.org/details/GakmanNaomiDIMM and programmed the file Naomi_DIMM_4.01_Update.bin file sucessfully. Checksum is 0x1058 8BAA according to Xgpro.
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Prepped the board with tons of kapton tape to protect the surrounding plastic connectors and got the original 56-pin chip out (it's the one on my finger). Tinned the unused pads and got it soldered. Boy, aren't these TSOP packages finnicky! Had to do a few touch-ups before I could guarantee that all pins were solid under the microscope.

Reassembled the NetDIMM and... I can see the lights flashing in sequence now! Previously it just flashed one led quickly and turned off. So, I guess it IS loading the BIOS I flashed.

Here's the video:
View: https://youtube.com/shorts/orbgTceTqrE?feature=share


Still get an error 22, though. Already tried re-seating it a few times to no avail. My regular Virtua Tennis cartridge loads fine, so the Naomi is okay.

Next step is to plug in the serial port and check out if it is indeed booting up. :rolleyes:
 

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doccaz said:
Soldered the darn thing to the adapter, had to fiddle with it at least half a dozen times to make sure all the pins were soldered and making contact properly.
Click to expand...
Now this is some extreme dedication to the craft :) Would love to know what kind of gear you have that you can so casually solder and desolder TSOP48 - its a sweet piece of workmanship
 
hatmoose said:
Now this is some extreme dedication to the craft :) Would love to know what kind of gear you have that you can so casually solder and desolder TSOP48 - its a sweet piece of workmanship
Click to expand...
Thanks! Not much really. Just a cheap hot air gun, a T12 soldering station, a microscope, tweezers, lots of flux, and way, way too many hours watching PCB repairs on YouTube, I guess :D
 
Reporting back: the daughterboard does recognize when a cable is plugged in, and I can see that network traffic makes the LEDs blink as expected. The NetDimm turns on the two red LEDs at the corner. But I still get an error 22.
I enabled the serial port on the NetDimm (set the jumpers JP3 and JP4 -- note that the pin 1 is on the opposite side when compared to the other jumpers according to the markings!).

Plugged in a serial cable (tried null modem, which is expected for a console) and straight thru. Nothing comes back, except an occasional dirt byte when I turn the Naomi on.
Re-checked the solder job on both the TSOP-48 and the filter, all okay, no shorts.

Voltages read 3.25v, 4.94v and 12v measured at the filter board with everything on. I *think* these are okay (right?)
Also, since the NIC appears to be functional, would this daughterboard work on a different non-net DIMM?

Any suggestions?
 
Alright, after some quality time with the Namco System 256, I took the DIMM apart for the nth time.

I desoldered IC36 (the BIOS), placed it on the programmer again, and read/verified it against the image. Checks out perfectly.
I cleaned the pads and traced them around the board to make sure none of them are broken. Noticed that one pad was slightly lifting (which according to the Macronix datasheet would be D8. So I reinforced it right at the very border with a drop of UV solder mask, Resoldered the chip back, and tested all pins for continuity with the pads. Reassembled everything and... error 22.
The serial terminal shows me nothing. I can see the NIC daughterboard initializing, and it even negotiates a 100mbit duplex connection with my notebook ethernet. No traffic coming from it, but it appears to receive all other traffic (the RX TX LEDs blink). The DIMM board lights up the two red LEDs and provides power to the NIC just fine, but nothing else.

So I'm at a loss here. Anything else I should be looking at on the DIMM board besides the buffer IC (which I already replaced)? Capacitors?
 
Ok, plot twist: was looking at this thread about firmware upgrades for the NetDIMM and noticed that the recommended way to upgrade to 4.01 is to go from 3.17 first, then update it via network to 4.01. That got me thinking, well since I'm already at a loss here, I'll program another chip with 3.17 and substitute it again on the motherboard.

Well, remember the pin I tacked with UV solder mask because it was starting to lift?

IMG_20230111_230735145_HDR.jpg



Meet Mr. Lifted Pad himself, in all his glory! :P

So, after a tedious track repair and soldering the chip with 3.17... it comes back to life, and even tests okay, finally!

IMG_20230111_225559872.jpg



... but I cannot set the IP address or even try to clear the settings, I get "DIMM Board timeout":
IMG_20230111_225755388.jpg



We're almost there. Where are these settings stored on the board?
 
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Congrats! I've been following this thread quite a bit and been hoping you'd get it! Congrats to you, I unfortunately don't have microsoldering skills to fix ripped pads :(

In my experience, the unable to set IP addresses has been due to faulty memory. I've had it twice and both times I replaced the sticks and it worked fine.
 
mR_CaESaR said:
Congrats! I've been following this thread quite a bit and been hoping you'd get it! Congrats to you, I unfortunately don't have microsoldering skills to fix ripped pads :(

In my experience, the unable to set IP addresses has been due to faulty memory. I've had it twice and both times I replaced the sticks and it worked fine.
Click to expand...

That was exactly it! I had a couple more memory modules around, swapped for another one and it worked fine!

Thanks!
 
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