Photo guide to replacing Sega CD 2 RAM battery

[balkiry]

This topic has been covered before in omnedon/Steve Logan's excellent 2003 post. However the process can be a little intimidating the first time, so here is some visual support.

These pics show a Sega Mega CD 2 RAM battery replacement. Naturally I take no responsibility for damage to your unit if you follow them. They are a quick once-over, so for more written detail refer to Steve Logan's post.

http://lh3.ggpht.com/_NhTDDrbbgpU/TFi_qMWmrfI/AAAAAAAAAA0/JkreRWKLzaw/s640/step%2001.jpg
First you will need to remove the plastic shell from your Mega CD. Ensure no CD is inside, then flip the unit upside down and remove the 4 or so screws on the bottom. Turn the unit back the right way and pull the top free.
Inside, you will see the board is protected by this metal plate. We need to get at the board because that's where the battery is attached. Remove the 5 screws that are holding the plate down.

http://lh4.ggpht.com/_NhTDDrbbgpU/TFi_qj9RRDI/AAAAAAAAAA4/k9L6-nYBgxU/s640/step%2003.jpg
Take note of where the earth is connected. Under the top right screw.

http://lh6.ggpht.com/_NhTDDrbbgpU/TFi_qtDj64I/AAAAAAAAAA8/xJj0GI2VSbQ/s640/step%2004.jpg
Place the earth to the side for now, but don't forget to connect it back up when putting the plate back on at the end.

http://lh6.ggpht.com/_NhTDDrbbgpU/TFi_qo-3YKI/AAAAAAAAABA/HmMV5Y-LOSc/s640/step%2005.jpg
There are some prongs holding the metal plate down so you will need to free them.
Using a flat blade screwdriver, pry the prongs out from under the mega drive connection point. You will now be able to lift the plate free.

http://lh5.ggpht.com/_NhTDDrbbgpU/TFi_q12pOvI/AAAAAAAAABE/5irIAg-h860/s400/step%2006.jpg
To be able to work on the battery, it's easiest to remove the board from the mega cd. Currently, it is still connected via 3 cables running to the laser assembly. We need to remove them. Take note of where they go for when you are putting the unit back together.

http://lh5.ggpht.com/_NhTDDrbbgpU/TFi_-gw2FGI/AAAAAAAAABQ/4jobeNhxAnM/s640/step%2007.jpg
http://lh6.ggpht.com/_NhTDDrbbgpU/TFi_-8tGqVI/AAAAAAAAABU/S-4wtuGB5jg/s640/step%2008.jpg
These are hard to remove so take your time and be gentle. You don't want to slip and damage anything.
Use a flat blade screwdriver to pry them away slowly. Be careful not to pull the sockets free of the board, or the Mega CD is junk.

http://lh4.ggpht.com/_NhTDDrbbgpU/TFi_-1fI4nI/AAAAAAAAABY/_t7sXQ-YY8s/s640/step%2009.jpg
http://lh3.ggpht.com/_NhTDDrbbgpU/TFi__MuateI/AAAAAAAAABc/NAHJ_Ojoizo/s640/step%2010.jpg
Two last screws next to the mega drive connection point need to be removed for the board to be free.

Cont'd next post...

[balkiry]

http://lh4.ggpht.com/_NhTDDrbbgpU/TFi__J3DWSI/AAAAAAAAABg/ruoyOdrRTI4/s640/step%2011.jpg
The board is now free. This battery in the top left is what we'll be working on.
Take note of how the positive side of the battery faces up, and the negative down.

http://lh6.ggpht.com/_NhTDDrbbgpU/TFjAKRckr6I/AAAAAAAAABk/3B6gI6l1TbA/s640/step%2012.jpg
Use a thin blade to pull the clip free of the battery. It is soldered on, so it will be difficult. Take your time and be gentle. I recommend slowly curling up the edge of the clip, and sawing away at the connection with the blade.
Eventually the clip will "pop" loose.

http://lh6.ggpht.com/_NhTDDrbbgpU/TFjAKt7DZBI/AAAAAAAAABo/yQiJhTbymeY/s640/step%2013.jpg
Pull it back so the battery is exposed.

http://lh5.ggpht.com/_NhTDDrbbgpU/TFjAKpV-Q6I/AAAAAAAAABw/JpvF7FwD2fY/s640/step%2015.jpg
Gently bend the top clip back. The battery is still attached to the board via a bottom clip. Using the same method as before, use a thin blade to pull the battery free.
It's tricky and the clip's connection to the board is flimsy, so take your time. You don't want to pull the clip out of the board or you will have to solder it back on.

http://lh3.ggpht.com/_NhTDDrbbgpU/TFjAKwhjQfI/AAAAAAAAAB0/p8-lVv8jAxA/s640/step%2016.jpg
Once the battery is gone, straighten the clips back out with needlenose pliers.

http://lh5.ggpht.com/_NhTDDrbbgpU/TFjAUWurZmI/AAAAAAAAAB4/PiYah9LWLG0/s640/step%2017.jpg
Put some padding like cardboard under the bottom clip to give it some height. Then lay some electrical tape side-up under the clip.

http://lh6.ggpht.com/_NhTDDrbbgpU/TFjAUnLvzCI/AAAAAAAAAB8/wjc78Jdbcow/s640/step%2018.jpg
Put the battery on top (negative side down) and fold the top clip over it. Tape it up tightly so both clips have a good connection directly to the battery.
NOTE: you may choose to replace the battery with an original 2016, and you may choose to solder it back on. Take care if doing this as the battery may explode if overheated.

Once the battery is firmly in place, reattached the board, then the plate (not forgetting the earth) and then finally the plastic shell.
You're done!

It's worth noting that a 2032 battery is not rechargable. In around 5 years you will probably need to replace it again. For this reason, I don't recommend soldering a 2032 battery in place.

[izarate]

There are rechargeable 2032s: ML2032 http://datasheet.octopart.com/ML-2032-T17-Maxell-datasheet-524292.pdf

[megasdkirby]

http://cgi.ebay.com/Maxell-ML2016-ML-2016-Rechargeable-3V-Battery-w-tab-/160450020939?pt=LH_DefaultDomain_0

Is it possible to just replace with this?

[balkiry]

http://cgi.ebay.com/Maxell-ML2016-ML-2016-Rechargeable-3V-Battery-w-tab-/160450020939?pt=LH_DefaultDomain_0

Is it possible to just replace with this?

I looked at this battery too, but decided to opt for a standard 2032. From the looks of that picture, you'd have to pull off the clips anyway because the Mega CD uses a slightly wider top clip that attaches to the board.
I mean, it'd be nice to have an original 2016 rechargable battery in there, but when you factor in the price + it's even more fiddly + you will have to replace that too some day... well, it wasn't worth it for me.

[raylydiard]

thats the lazy way not being funny i just buy these
http://www.budgetbatteries.co.uk/21441/ml2016-size-lithium-3v-25mah-maxell-rechargeable-coin-button-cell-with-t26-style-pcb-tags/
prober replacements and i use pcb lacquer be for i put the new battery to protect the motherboard
check my feedback on http://www.assemblergames.com/forums/index.php
i offer replacement all i need is the motherboard
price of the battery + return postage
my user name on assembler fourms is raylyd
i have repaired a sega cd dev kit
i can even do the sega cdx systems i have a few of them my self 6 of them


I looked at this battery too, but decided to opt for a standard 2032. From the looks of that picture, you'd have to pull off the clips anyway because the Mega CD uses a slightly wider top clip that attaches to the board.
I mean, it'd be nice to have an original 2016 rechargable battery in there, but when you factor in the price + it's even more fiddly + you will have to replace that too some day... well, it wasn't worth it for me.