This upgrade was done for Andreas, who wanted a newer screen and battery installing in his Sega Nomad.
Sega Nomad Battery Pack Upgrade
As usual the Battery and charger of choice is the NP-F550 or compatible unit, and the Sony 2900mAh battery.
The task I’d been set by Andreas was to get the new Li-ion battery pack to be recharged by the original Sega 10v power supply. He initially requested that I replace the battery and leave everything else remaining in the Sega rechargeable battery pack. This is not possible because a charging circuit designed to charge NiMh cells is not compatible with Li-ion cells. At best it wont work, at worst it could meltdown. The solution is to either keep the PSU external to the battery, as I did in my first mod, or include it inside the battery pack.
The next thing to consider is that the Sega power supply is 10v and the camcorder battery charger requires 12v.
I read that other people had worked around this shortfall by using a DC-to-DC step up regulator. Essentially this allows you to input a voltage in its range and output a higher voltage.
This LM2577 Module allows me to step up 10v to 12v at a slight cost of current (Amps).
I tested this by connecting the module to a Sega 10v power supply (one from a Game Gear) to the camcorder battery charger, and connected the battery.
As you see the battery is now charging.
Next I wanted to be sure that I could physically fit everything in the Sega Nomad battery pack. You can see the camcorder charger PCB is quite large and has a number of large components
If you look at the underside of the board, its divided into two parts. Left side for DC charging at 12v, Right side for AC charging 110-240v. As I intent to provide 12v DC I can remove the entire AC side of the board. The AC side was only connected to the DC side by a couple of components so after they were de-soldered I could snap the board.
Now the charger is much smaller. Time to start fitting it all in the battery case.
Upon opening the Sega rechargeable battery pack, it was clear to see the old Ni-Mh calls are in bad shape. All the terminals and solders were furred over and corroded. Even the old charging PCB was affected.
I removed everything out of the casing, and removed most of the plastic internal molding with a craft knife to clear way for the new battery and PCB’s. the only part I reused was the original charging jack and connection pins to the Nomad. Once everything was out I could start placing the new component in.
Compared to the 6xAA battery holder there’s loads of room in the box it was fairy easy to get everything inside.
I tested everything out in place and once I was happy it was working I glued everything down with hot glue.
After some testing I changed the LM2577 Module to another module after I had concerns of the heat it was generating. The battery is charging just fine now from the 10v PSU.
Sega Nomad Screen Upgrade
The LCD on the Nomad is notoriously bad. Pale washed out colors and blurry motion make playing anything hard. Thankfully its fairly easy to install a new 3.5″ LCD Screen to give the Sega Nomad a huge makeover.
Installation of the new LCD screen went exactly the same as the one before. The power is connected to 5v, Video is connected to the underside of the AV port.
Before reassembling, I installed a replacement screen cover (also knows as a Lens) they are easy to get hold of on eBay and give the screen a scratch free finish. Removing the old one was harder than I hoped. In the end I found that using a plastic opening tool was the best option. I didn’t want to mark or scratch the edges around the screen with a knife.
With that in place it was time to put it all back together taking care to make sure all the buttons and D-Pad line up correctly with the boards. As you see the LCD driver board is glued in place with a layer of electrical tape underneath to insulate it. Its also important to make sure the power and video wires are not in the way of the button pads.
That’s about it.
Thanks for reading.
8bitplus – 2016.
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