NAOMI 2 supercapacitor

[TheJiggler]

Ive seen the super capacitors on the Naomi leak and cause corrosion but I can't for the life of me find any information on Naomi 2 super capacitors which are in a different spot to the Naomi. Well anyway I removed mine because it was getting to the point of leaking. The Naomi 2 still runs perfectly fine, what is it that the super capacitor supplys power to after shutdown? because as long as Ive got a working 3v coin cell it saves all system and DIMM settings.

 

[leonk]

bumping old thread for others to learn from my experimentation..

The Naomi 1 & 2 have the same super capacitor, located at C29. Many have replaced it to prevent the common leakage from destroying the main board. I decided to just leave it out. Not sure what it's for, but the system works perfectly (and holds data) with it removed.

I think it's a very good insurance policy to remove it, and keep it out if you want your system to last for a long time.

 

[max 330 megafartz]

i pulled mine as well, have seen no issues from doing so at all.

 

[leonk]

I was trying to come up with a reason for its existence and I can only think of 1 reason.

SRAM chips typically operate at 1 voltage, but can go down to a lower one to hold its data. For example, read/write at 5V but store data at 3V. So the cell battery is great for storing the data for long term (3V source) But when you turn off the power to the machine, Naomi wants to write book-keeping information to the RAM. With only 3V from the battery, it might not have enough juice to do so. So the super cap gives it the extra kick it needs to write the data and shut down.

For us home users, we don't care about this kind of "cleanup data" so the super cap is not needed.

 

[TheJiggler]

Good to see others are doing the same. Im going to remove the supercap from my N1 too.

Not a bad analysis leonk. I think you've hit the nail on the head.

 

[Obiwantje]

Or just spend $1.64 for a replacement, that is what I did.

This is the link for them @digikey

http://www.digikey.com/product-sear...us&keywords=P10787-ND&x=17&y=19&formaction=on

 

[leonk]

Or just spend $1.64 for a replacement, that is what I did.

This is the link for them @digikey

http://www.digikey.com/product-sear...us&keywords=P10787-ND&x=17&y=19&formaction=on

Problem with replacements is that you'll need to do it over and over every decade or so (just like replacing batteries in CPS2 boards) or you can just remove it and never worry about it ever again.