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Project DVD Player Mod
    Purpose
The purpose of this documentation is to demonstrate how I modified the Philips PET941D portable DVD player to run off of external AAA batteries. By default the portable dvd player contains an internal, rechargable block battery manufactured by Yoku in China (4.23VDC/8.43VDC). However, when you use up the power provided by that internal battery you can't use the portable dvd player again until (1) you find a 120VAC source, or, (2) you find a 12VDC source such as a vehicle.


By adding the external AAA battery option, you could power the dvd player with the yoku battery, then as many sets of AAA batteries that you may have available (assuming you don't have a AAA battery charger) doubling, tripling, quadrupling (or more) the play-time. If you are wondering what the power support requirements of this device (or your own device) is in a solar setting, check out the solar calculators.


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  1. Open the portable dvd player (screws on the bottom as well as three in the DVD bay area).
  2. The yoku battery is attached to the bottom casing with an adhesive tape so it will take a bit of time and care to pull it away.
  3. Once the battery is free, remove the double-sided adhesive tape.

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  1. Clip the cable connected to the yoku battery. Leave enough cable attached to the battery so that the insulation at the end of the cables can be removed and butt connectors attached.
  2. Clip the female end of the DC Fan Wire Extension so that approximately 2 - 3 inches remain. Strip the insulation off of each of the three cable leads.
  3. Drill a small hole into the bottom casing of the dvd player. Feed the three wires from the female end of the DC Fan Wire Exension through the hole, from the bottom up (you want the female head to be outside of the bottom casing.
  4. Connect each lead to a butt connector. Then strip the three power wires coming from the IC board (which were connected to the internal battery). Attach the red to the red of the DC Fan Extension with butt connector, black to black and white to yellow.

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  1. Assemble the portable DVD player. When you flip it over you will see the female head of the DC Fan Extension exposed outside of the casing.
  2. Glue the female head to the case (make sure to place it properly so you can connect the male end to it).

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  1. Connect (using butt connectors and stripping insulation off the ends of wire) the male end of the DC Fan Extension wire to the yoku battery.
  2. Be sure to connect red to red, black to black and yellow to white.

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  1. Pair up the AAA battery holders.
  2. Using a butt connector, connect the negative (black) wire of one to the positive (red) wire of the other with a separate length of wire also connected. Do this for each set of two.

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  1. In this step I connected the male end of the second DC Fan Extension to one pair of battery holders (black to black, red to red, and the red/black to the yellow).
  2. UPDATE: After a trial run found out that one pair of battery holders (6 AAA batteries) only provides 35 minutes of DVD run-time. Therefore, to provide greater run-time, the black wire of each set (a set contains two battery holders) are connected together by a butt connector. Likewise the three red wires are connected together. The red/black connections (with the extra length of wire) are connected together. After that is all connected together attach the DC Fan Extension male wire together (black to black, red to red and the red/black pairs with extra wire are connected to yellow).

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  1. Before gluing the battery holders to the bottom of the casing (if that is what you want to do), run a test to make sure all of the wiring connections are okay. If they are, the DVD player will play.
  2. UPDATE: In this trial run, initially only one set of battery holders were wired up. However, as can be seen, the wiring was okay and the dvd player operated.

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  1. Once you have a successful test, glue the battery holders to the bottom of the casing.
  2. UPDATE: In this trial run, initially only one set of battery holders were wired up.

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  1. In this updated picture, all three sets of battery holders have been glued to the casing.


So What is the Total Run-Time?
Number Batteries
Battery Type
Voltage
mAh
Information
1
Yoku
4.23VDC/8.43VDC
unknown
Approximately 230 minutes of DVD play time (3 hours and 50 minutes).
6
AAA
4.2VDC/8.4VDC
1000/2000
Approximately 35 minutes of DVD play time (this was not enough which is when I went back and added more).
18
AAA
4.2VDC/8.4VDC
3000/6000
Approximately 205 minutes of DVD play time (3 hours and 25 minutes).


DVD Player Behavior with Batteries
Whether the Yoku battery is plugged in, or the AAA batteries, I've noticed that the Philips portable DVD player will not turn on unless the batteries are within virtually 100% charge at 8.4VDC output. I charged the Yoku battery (as well as the AAA batteries) and attempted to use them ten hours later. Because each had lost some tiny amount of voltage, that normally insignificant amount of loss apparently is too much for the player.

This leads me to believe the intent of the integration of the internal battery is not based on mobile practicality (my interpretation of portable) but rather a product design after-thought. With regard to the AAA batteries used, it may be possible to overcome this product shortcoming by using six 4-cell AAA battery holders instead of the six 3-cell AAA battery holders. While this will increase voltage output (which may or may not cause damage to the portable DVD player), it also means that the insignificant amount of voltage loss by the batteries over such a short duration of time would not be great enough for the portable DVD player to not turn on.

Another option that would be useful is the use of 1.5VDC AAA batteries in the existing six 3-cell AAA battery holders versus the 1.2VDC batteries (charged to 1.4VDC). After considerable research, I found AAA rechargeable alkaline batteries rated at 1.5VDC/800mAh called "Pure Energy Rechargeables". While these rechargeable batteries do not have the characteristics of Nickel-Metal Hydride, they are nonetheless rechargeable, fairly new on the market and sold in Canada. I'd recommend these batteries...provided you can get them in your area.

Project Materials
[1] Philips - 9" Portable DVD Player #PET941D
[1] 22-18 Gauge Insulated Crimp-On Butt Connector (16-Pack)
[2] Link Depot 12" Power Supply 3 Pin Fan Extension Cable Model POW-12-EXT
[5] 4-Pack, Lenmar PRO410B 1.2VDC/1000mAh Nickel-Metal Hydride Rechargeable AAA Batteries (Used in this documentation)
[3] 8-Pack, Pure Energy Alkaline 1.5VDC/800mAh Rechargeable Batteries #RN03-8 (Preferred for the DVD player although you may only get 50 deep recharges out of them)
[6] AAA 3-Cell Battery Holder
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