Sega-Naomi

Hi everyone



I have a dedicated HOD3 machine in my collection which recently began to act irradicly. On random times the game will freeze up and won't do anything anymore, the image on screen stays frozen and it doesn't react to controls or test inputs.



So far I've done;



- measured the voltages and especially monitored the 5v for a while

- just to be sure swapped the power supply with another known good one

- Replaced the DIMM's with new ones

- Replaced cooling fan in the Chihiro unit

- Checked all connectors and wires

- cleaned the gd rom and drive



nothing worked and I don't really know what to try next.



Suggestions?



Thanks in advance

Hi,



I had the same problem with a chihiro mobo. It was the three axial capacitors (3300uF if i remember well) closed to the CPU heater who were dead. Check they and replace they if needed.



PaT.

Common fault for the large 3 caps near the heat sink to fail, normally the leak.



Memory caps IIRC.

Ok, now I'm a little confused. Next to the heat sinks are 5 capacitors of 1500 uF each. There is a group of 3 capacitors (also 1500 uF) at the corner of the main board.



I can't seem to find any that are 3300 uF. Can anyone clarify just to be 101% safe? Replace the 5 caps next to the heat sink?



Oh yeah, those Chihiro boards are a joy to screw open. There are a gazilion screws!

There was only three 3300uF caps on my mobo. Anyway the total capacity of the surface area must be the same with five 1500uF caps. So i suggest you to change all five caps there are on your first picture.

Ok, I guess replacing them wouldn't hurt. I'll post the progress!

Be careful and patient when replacing these. These PCB's are multilayered, and it can take quite some effort to neatly remove these things.

Update:



The caps are replaced with new ones. The machine runs a lot longer now than before but it's not solved. At a certain point the screen goes black and the 2 status leds on the front of the Chihiro blink continiously...

Update:



The caps are replaced with new ones. The machine runs a lot longer now than before but it's not solved. At a certain point the screen goes black and the 2 status leds on the front of the Chihiro blink continiously...