Naomi repair?

I've never had to actually fix a Naomi, but pop it open anyway, let's go through the usual steps.

Any visible damage on the board? I don't know what Sega's PCB labeling scheme is, but if you find anything that has two pins and is labeled with an F, do a continuity test on it. You might get dumb lucky.

Hook it up to power, then feel the surfaces of ICs. Do any get a little too warm after a few seconds?

The CPU is 200Mhz, which makes me think maybe a logic probe might not be all that useful... you could poke around anyway, shouldn't hurt anything. If you have anything you're unsure about, I have a working Naomi you can compare against, and will be getting a logic probe soonish.
 
define "bad switcher"

if your +5 voltage walked beyond what this board can handle, then you're probably looking at a damaged board. 5.10V is like the max they can handle, I've even seen a couple work up to 5.20, with a low end safe operating voltage of 5.00V even. it's a sophisticated piece of hardware though that has very sensitive components.

was it an original power supply that the NAOMIs shipped with (a 3.3V type) or was it a hacked up one modified to work with it? cause you have to be mindful that the usual colors of red, black and yellow are not +5, ground and +12 on Sega's shit. Sega's scheme is yellow, white, red, brown for +5, ground, +12, and +3.3 respectively.
 
switcher released it's magic smoke a few years back mid game of Capcom Vs Snk. it's been on the shelf ever since. thinking its what may be a bad mosfet of some type (power up to it, nothing past it)...just no idea how im going to remove it.
 
Pull the cart... pull off the top of the case. You'll see a couple of voltage regulators there.

Power it up, check the voltages going into the system AND check the voltages coming off the regulators on the NAOMI board itself.

Another common way for the NAOMI boards to die is for the 8 pin serial EEPROM next to the big socketed BIOS ROM to have its traces eaten up by a leaking super cap next to it.
 
Back
Top Bottom