A couple of blog posts ago I shared my design for a Mobile Marine WiFi Entertainment System. The back bone of the system involved an AppleTV (ATV) for mirroring iPad video and apps to a TV or monitor. Apple AirPlay would be used for streaming music to AirPlay speakers and devices. The problem with the ATV is that is does not work well on smaller boats that don't have the 115 volts needed to power the device. In this post I will show you how I converted my AppleTV to 5 volt USB power.
The ATV has a micro USB on the back of the device but this cannot be use to power the device. This is only used to tether it to a computer to restore and update the software.
After a little research I found a post on IFIXIT that showed a conversion to DC of an ATV. This IFIXIT teardown article showed that the ATV has a power supply that converts 115V AC to 3.4 volts DC with a current of only 1.75 amps.
Warning! Please unplug your AppleTV before attempting to open the case or make any modifications. These modifications will void your ATV warranty so do not proceed if you want to keep it intact.
The conversion only cost me about $5 bucks to do. I had all the needed tools and a spare USB cable.
Rosin Core solder
20 gauge wire
heat shrink tubing
plastic spudge or knife
Small Torx , regular and Philips screw drivers
New 5 V DC power supply (Amazon $4.85)
I picked up two of these for about $9.00. It has a DC input voltage range from 4 to 30 volts and an adjustable output voltage of 1.23-30 volts. So I could power the ATV with either 5 volts or 12 volts on the input side. In my conversion I chose the 5 volts input.
The size was just right and it fit perfectly in place of the old ATV AC power supply.
The current output of 3 amps was large enough to replace the 1.75 amps of the old power supply.
* Size:Approx48*23*14mm (Length*Width*Height)
* Type: LM2596 Adjustable Power Supply Module
* Input Voltage: DC 4V-35V
* Output Voltage: DC 1.23V-30V
* Output Current:3A(Maximum)
* Conversion Efficiency:92%(Highest)
* Output Ripple:30mv(Maximum)
* Switching Frequency:150KHz
* Load regulation:0.5%
* Voltage regulation:2.5%
* Work temperature:-40?- +85?
* Quantity:2pcs as A Set
The ATV case is made of hard black plastic. Removing the lid is actually the hardest part of the project. The lid can be removed by taking a sharp plastic spudger, screw driver or knife and inserting in the joint between the cover and the case. There are seven plastic tabs that hold the cover on.
It is easiest to start at the back of the device between the HDMI, USB and network connections. The tab in this area is a small one that is easily popped out. Once you release this first tab move around the box popping the other out as you go.
I took a small side cutters and cut the tabs off of the cover so I could easily open the case again if needed.
Removing the Old Power Supply:
There are only two screws and a little sticky tape holding down the old power supply. First remove the two small Torx screws at the base of the power plug. I did not have a Torx driver so I used my small Philips screw driver and it worked just fine.
The old power supply minus the black cover is shown at right.
Next note the orientation of the 8 pin connector on the old power supply. This will be important to make sure you connect the proper wires to the new power supply. Remove the 8 pin connector from the socket where it connects to the chassis.
Next pry the old power supply out of the case. I started from the back of the case at the base near the plug and the sticky tape came loose easily.
With the back of the ATV towards you(the side with the HDMI, USB and network connectors) note the 8 pin connector, from left to right the two left most wires 1 and 2 will not be used. These were for the old temperature sensor.
Wires 1 and 2 not used
Wires 3,4 and 5 are the - negative ground wires (twist these together)
Wires 6,7 and 8 are the + positive power wires. (twist these together
Solder the ends of the 20 gauge wire to the new power supply +positive and -negative output terminals.
The input to the power supply will be fed with two wires from a USB cable. I had plenty of these laying around so I clipped the end off and exposed the wires.
The black wire is the ground and was connected to the - Negative terminal of the input side of the new power supply. The red wire is the + Positive supply and was connected to the + terminal on the input of the new power supply. Cut off the green and white wires, these will not be used.
I reused the grommet from the end of the USB cable and used the glue gun to secure it to the case through the old power plug opening.
Adjusting the power supply:
Do not re-connect the 8 pin connector to the unit until you have adjusted the output voltage of the power supply. Plug in the USB cable into a 2.1 amps USB source to provide power to the new power supply. I used my iPad charger to test it during the installation.
Set your volt meter to DC volts and measure the output terminals voltage. Adjust the gold colored screw on the blue component on the power supply until you have 3.4 volts measured on the volt-meter on the output terminals.
With the output voltage correctly set unplug the USB cable from the power supply. Now re-connect the 8 pin connector and plug the UBS cable back in to power up your AppleTV. Congrats your done and you can now enjoy using your ATV in your car, motor home or boat.
On my boat I use a USB insert in my 12 volt power outlet. It provides either 1 amp or 2.1 amps of USB current. The 2.1 amp connection should be used to power the ATV.
These can be picked up at any auto parts store for about $10 bucks
12 Volt DC Supply Option:
The ATV could also be powered from a boat or car's 12 volt power source. The same DC power supply used above has a large enough voltage range so it could be powered on the input side by 12 volts instead of 5 volts.
A barrel adapter like the one to the left would be mounted on the back of the ATV and connected to the input side of the power supply. Solder the + positive input to the center post and the - negative input onto the outer connector on the barrel adapter.
Make sure to remove the 8 pin connector before you connect the 12 volts on the input and while you adjust the output voltage on the power supply to 3.4 volts.
A 12 volt power plug could then be easily connected to the ATV with the barrel connector jack. Most of the 12 volt car adapters are 5.5mm x 2.1mm.
To use your ATV at home with this set up you would need a switching power supply that plugs into 115 volts with an output of 12 volts and at least 2 amps and a compatible 5.5mm x 2.1 mm barrel adapter.
Enjoy your new mobile AppleTV.
~~~ Sail On ~~~ /)