View Full Version : SEGA CD RAM battery replacement -accomplished!!!!

06-25-2003, 10:07 PM
All you need is a regular CR2016 lithium battery. It's not some wacky battery, like the SEGACD FAQ seems to suggest. I just did it to mine (SEGACD2) and to a working dupe. It's just like changing a cart battery, except a bit trickier to get inside. When popping the spot welds take care, as the posts are not that tightly secured to the SEGACD. It's far safer if you have a soldering iron handy, if you need to re-attach a post.

Take your time, and have some needlenose pliers, a small thin prying instrument, and patience. I simply attached the new battery with electrical tape and cardboard (for pressure).

It works great! No more RAM INITIALIZATION FAILED PLEASE FORMAT messages. The games just play!!!

Watch next week in buying and selling for my Ebay auction for a sweet restored Genny 2, SEGACD2 (with new battery installed!), and 32X set, with assorted games of each type. =)

06-26-2003, 08:41 AM

I hope you commanded it to "WISE FWOM YOUR GWAVE!" (I find this lends an air of formality to the resurrection of dead components.) 8-)

07-21-2003, 10:46 PM
Could you be kind enough to post some detailed step by step instructions for doing this?

It seems the battery in my Sega CD Model 2 is dying and I'd like to replace it -- only I don't think I have any of the tools you mentioned, nor have I ever done a battery replacment before, nor can I find where in the unit the battery is!

Thanks. :)

07-22-2003, 10:14 AM
My first try at one of these, so go easy on me!

These instructions are for SEGA CD model 2 RAM battery replacement. Once successfully performed, this procedure will restore save functioning to your SEGA CD 2, and stop RAM initialization errors. These instructions are informational only, and I take no responsibility for what you may do to your SEGA CD 2 if you follow them. You should be comfortable handling circuit boards, and take anti-static precautions.

Stuff you will need:
CR2016 battery
Needlenose pliers
Thin prying instrument (flat blade optical screwdriver will do)
Phillips screwdriver
Electrical tape
Multimeter (optional)
15W soldering iron and solder (optional but if errors are made could be required)
and about 45 minutes

Make sure no CD is in the CD drive. First, flip the CD2 upside down. Remove the 6 gold screws underneath and place them in an empty egg crate or some other safe and organized location. Turn the CD2 back over, and you can now gently lift off the cover. You will now be looking at your naked CD2. You will see the laser assembly on the right, attached with cables to the circuit board. The circuit board is still hidden by shiny RF shielding. That RF shielding goes next.

Around the edges of the RF shielding, are more screws. Remove all of them and place them neatly (and separately) from the screws that held the outer case on. Before removing the RF shielding, you should gently pry out two little metal flaps of shielding that are wedged underneath the Genesis connector slot. Once that’s done, the RF shielding should lift right off the circuit board.

Next, gently and firmly remove the cables that are connected to the circuit board and the laser assembly. Remove them from the circuit board, carefully noting where you are pulling them from. Make sure you are grounded with an anti static wrist strap, or you discharge yourself on a piece of metal (not attached to the CD2) before handling the Circuit board directly. There should be three harnesses. I recommend using an optical flat blade screwdriver to gently pry/work the harness plugs from the harness sockets. TAKE CARE with this. If you pull one of the sockets off of the circuit board, your SEGA CD 2 is garbage. If you rip one of the wires out of the plug, you will need the wires replaced from another SEGA CD 2. This isn’t really that hard, but it is one of the points where if you carelessly tear something, you will have broken your SEGA CD 2.

Now we’re ready to remove the circuit board itself. On either side of the Genesis connector slot is a screw. Loosen off each of these screws. There is no need to remove them completely. Now you should be able to lift the circuit board out completely. Make sure you are grounded with an anti static wrist strap, or you discharge yourself on a piece of metal (not attached to the CD2) before handling the Circuit board directly. Once it’s out, make some room. You don’t need all of that other stuff right now, so get it all out of the way.

Now, you should have the CD2 circuit board in front of you. With it oriented with the Genesis connector pointing to the left, you should easily spot the battery in the upper left hand corner. That is where the action is going to be.

We are going to be doing some prying and bending next. One has to be very careful not to slip, or use too much force. One hard slip of a tool, and you could scar the circuit board, tear off a capacitor or worse. TAKE YOUR TIME. You’ve made it to a total disassembly of your SEGA CD 2, there is no need to rush now.

Re–orient the board so the battery is right in front of you and easy to get at. We need to pry the spot welds free. I like to wedge the thin wide flat end of an optical screwdriver underneath the top metal tab spot welded to the battery. Pry it up just a little bit, just enough so you can grab the bent up bit with the needlenose pliers. These little metal bands that are holding the battery in (and are conducting the battery power to the circuit board) are NOT secured to the board that tightly. If you can avoid tearing them right out, you can avoid using the soldering iron to put them back in =). Now you’ve got a bit of the metal band gripped by the needlenose pliers. With one finger pressing down on the battery, pull on the metal band with the needlenose pliers. I’ve found it easiest to “curl” it off. You can always re-flatten the metal band after. Once that band is free, you need to do the bottom one. With this part, take the needlenose pliers, and grab the metal band under the battery and hold it there, DO NOT PULL. Grab the battery with your other hand and pull it off the band. Your grip with the needlenose pliers is to hold the band in place while you pull hard on the battery. It is best to not pull that band out of the circuit board, or you will be forced to solder it back in. Once the battery is free, you can toss it out, and the hardest part is over.

The metal battery bands should be bent all out of shape by now. Take the needlenose pliers and flatten them out again. Take care to not twist ‘em out, or otherwise bend them anymore than necessary. Now take a thin piece of cardboard, and electrical tape it to the circuit board (about ½” square) directly under where the battery is going. This is to give the battery some lift and pressure. Now press the newly re-flattened bottom battery band down, on top of the electrical tape. Take the new CR2016 battery, and place it -lettering up- on top of the bottom metal band. Now, take the top metal band, and bend it down onto the top of the battery. You need a solid connection here. I take the needlenose pliers in the closed position, and press firmly on the top of the metal band, making a kind of crimping. Now take another square of electrical tape, and secure the top band to the battery, as flat and as firmly as possible. Now if you want to test your connections, get your multimeter out. Flip the board over and find the three little tines sticking out directly under the battery mount. Take the multimeter leads, and touch one to the single tine on one end, and the other to either of the two tines on the other. Depending on where you put each colour lead, it should read 3.3V or –3.3V. It doesn’t matter which, as long as you installed the battery lettering up. Once you are happy you have a good connection, you can consider placing a 3” length of electrical tape from the top of the battery to the underneath of the battery mount under the circuit board for extra holding power.

Now you can re-assemble, working backwards from the 4th paragraph above. Enjoy saving on your SEGA CD 2 again! Please do not re-distribute or re-publish without the author’s permission. C.2003 Steve Logan

07-22-2003, 10:43 AM
Christ, I'm sorry I asked. That's WAY out of my league. Not to mention I really don't have any of those tools and really don't want to take the risk of destroying my Sega CD. None of my friends are any good at doing this kind of thing either.

Oh well, I'm sure the instructions will be of help to someone. Thanks! :-D

07-22-2003, 02:18 PM
Well, if you don't mind shipping, I'd do it for anyone who asked, for $20USD plus actual return ship. That includes the battery. I've done 3 so far, with no problems or soldering required. I've got a 4th waiting for me in the basement. :)

07-22-2003, 03:03 PM
That's very nice of you to offer. Is payment by PayPal okay?

Send me a PM with your information.

07-22-2003, 04:11 PM
Thanks for the heads up on the CR2016 type, omnedon. I'll probably route a battery holder with some wires away from the actual board when I do mine, to keep any leakage from damaging the insides. It'll make future insertions easier too.