Dreamcast Battery Mod

[Gizmo613]

Here is the Battery mod from rechargeable lir2032 to regular cr2032. I choose to do this because they are cheaper and easier to find. Plus the purchase a whole lot since the vmu uses 2x cr2032 and i have a Pokemon Go Plus that also uses the same battery.

Parts:
1x 1N4007 Diode
1x CR2032 battery holder
Soldering Iron


First disassemble the Dreamcast by removing the modem and 4 screws:


Then remove the controller board which houses the battery and charging/limiting resistor.
4 screws, the fan plug and the ribbon needs to be removed first. (Note: On some boards, the power supply board needs to be removed as there is a tab that sticks out over the controller board. Mine did not.)


Once the board is out, desolder the battery and resistor(Note: There seems to different boards with the resistor in different locations. On my board here, it is right next to the battery and marked R1 with the resistor symbol. )

Install the holder and diode. (Note: Different boards will have the diode mounted differently. Make sure the cathode, the gray line, is going towards the ribbon connector. Follow the traces!!)


Now reinstall the controller board and add your new battery!



I tested it by starting the console and entering the date and time. Then turned it on and off to make sure the date was saved. Now enjoy not having to enter/skip the date and time every time you turn on the Dreamcast.

Next stop...... IDE/SATA hdd mod!!
I've designed some QSB for the dreamcast hard drive mod. This will have a ffc connector so that you won't have to cut your case up. Another board i designed will allow the removal of the GD-Rom drive. So stay tuned!!!

[Brian 503]

No led mod, just kidding.

[Gizmo613]

lol not yet. Trying to find a green Dreamcast logo sticker first. Gotta match my buttons.

[RDC]

On that VA0 version Sub Board 01 there, you can just desolder one lead or cut R2 instead of doing the Diode install at R1. It's already protected on the motherboard via D602, and the charging circuit comes from D603 on the motherboard thru R2 on the Sub Board, so no R2 in there, no way for the DC to try and charge the battery, so no need for the R1 to Diode swap.

Now on the VA1 and VA2.1 versions, Sub Board 2 and Sub Board VA2, removing R1 and installing a Diode for sure needs done, as they changed those boards and motherboard layout, so that charging circuit is on the same line. It would also be better to use a 1N4148 versus a 1N400x in that case also.

[Gizmo613]

Oh, that is great to know! 

[Gizmo613]

On that VA0 version Sub Board 01 there, you can just desolder one lead or cut R2 instead of doing the Diode install at R1. It's already protected on the motherboard via D602, and the charging circuit comes from D603 on the motherboard thru R2 on the Sub Board, so no R2 in there, no way for the DC to try and charge the battery, so no need for the R1 to Diode swap.

Now on the VA1 and VA2.1 versions, Sub Board 2 and Sub Board VA2, removing R1 and installing a Diode for sure needs done, as they changed those boards and motherboard layout, so that charging circuit is on the same line. It would also be better to use a 1N4148 versus a 1N400x in that case also.

RDC, I have a DreamCast VA1 with Sub Board 2 for the controller port. I'm going to be doing the CR2032 battery mod. Wouldn't removing D603 disable the charging circuit? If so, a diode would not be needed correct, since D602 is already protecting it?

[RDC]

You could do that on the VA1/VA2.1 motherboard versus removing R1 and installing a Diode on the Sub board. That means pulling the motherboard and desoldering SMT versus just messing with thru hole on the Sub board. Removing D603 would be harder to put back to normal if one wanted versus redoing the Diode/Resistor on the Sub board, but either way will do the same thing there, boils down to personal preference really.

[Gizmo613]

Oh yes! I think I'll just lift the pin leg of d603. When I do lift the pin leg, on the controller board, could I leave the resistor in tact? Or should I remove that and add a jumper?

[RDC]

Make sure you lift pin 1 or 3, lifting pin 2 will do jack all.

If you remove R1 the battery voltage can't get to the motherboard. No real advantage to swapping it with a jumper.

[LSL]

I prefer to move or remove, on the Katana board itself, the resistor responsible for the rechargeable battery supply voltage. There is a 0% chance of replacing a rechargeable battery in the future.

On VA0 and VA1 it is R612 (130 Ohm). In VA2.1 it must be the same resistor (I'm not sure). Os esquematicos ajudaram a fazer: https://acidmods.com/forum/index.php?topic=44892.0