The following is more of a public service announcement than a repair. I have owned the same Naomi 2 motherboard for about 5 years now. I use it on and off in my personal collection and have never had an issue with it. A few weeks ago, I tried to boot the system, and unfortunately it was stuck on a black screen, completely unresponsive. I could see the power LED’s turning on, the fans would spin up, but it would never make it to the boot sequence. I was especially frustrated as it was working a few weeks prior before going back in storage.

I did some reading online, this is apparently a very common issue on both Naomi 1 and Naomi 2. There is a 5.5v 0.1uf super capacitor near the bios. This capacitor is known to leak, and when it does, the 5v levels become unstable causing the Naomi to not boot. The fix was relatively straight forward, install a new super cap. I was able to find a Panasonic OEM replacement for about $5 including shipping.

It was actually really difficult to remove the old cap, the ground and 5v traces quickly absorb the heat from the soldering iron. I ended up cutting the capacitor off of the board and removing the legs with tweezers. Once removed, I used wick and a lot of patience to clear the holes. It was slow moving but eventually became clear, be sure to use the largest solder iron tip you have. Once the holes were clear, I used white vinegar on a q-tip to clean the surrounding area on the parts side of the PCB. The cap had indeed leaked, and rusted on the bottom. Fortunately I caught it in time, before the electrolyte destroyed any traces.

Installing the new capacitor fixed my Naomi 2. It has been running reliably since installing the new cap. If you own a Naomi, and the super cap has not been serviced, I would strongly recommend checking it before its too late!

I received a “fully working” Vendetta PCB off of eBay for a reasonable price. Unfortunately when the board showed up, I immediately noticed there was something wrong with the audio. Any time a speech sample tried to play, it sounded like a static explosion! I unfortunately (maybe a good thing lol) did not capture the ear-splitting bad-audio state with video, but trust me, it was terrible!

Like most audio issues, I started with the basics. The capacitors checked out OK. Since the BGM was fine, I didn’t need to test the FM section of the audio circuit. I tested the Op Amps and observed the audio was bad at this stage as well (so that told me the amplification section of the audio circuit was likely OK).

I did not find a dedicated DAC chip on board, which is likely where the fault was going to be. I did some research and discovered the Konami 053260 IC is responsible for digital analogue conversion (DAC).

I was certain this chip was faulty, however I sadly did not have a donor on hand. After doing some research, it would seem Golfing Greats and Roller Games both have this IC on board, and they are both relatively inexpensive. I found a faulty Roller Games PCB for a reasonable price, and decided to purchase it to use as a donor for my Vendetta. I pulled out the hot air and swapped the IC:

SUCCESS! All audio has been restored and the digital samples are playing crystal clear!

I received a very nice condition Gradius II: Gofer no Yabou pcb from my good friend Robotype. It was sold to me as faulty, described as “the drums are missing from the audio”. The game showed up, and YUP, the drums are certainly missing!

This was an ESPECIALLY odd fault. In my experience, the Background Music and Samples either work or they do not work. I have never seen working, but instruments missing! I started with the logical audio failure points… YM2151  FM synthesizer (tested OK), YM3012 Digital Analogue converter (tested OK) and finally the UPC324 Op Amps (also tested OK). With all of the major audio failure points checking out OK, I decided it was time to try a more aggressive strategy. I turned to the mame source, and determined Konami Custom ‘007232’ is responsible for audio generation. This seemed like a good starting point… luckily for me, my scrap X-Men PCB had this IC present. Time to remove and swap the IC!

SUCCESS! The newly fitted ‘007232’ custom Konami Audio IC did the trick, the drum line is fully restored and the BGM is back in all of its awesome glory. Job done!