By
Nospheratu
This modification involves going a step further than a straight ID chip swap between the 240W and the 330W. The reason I chose this method was, I did not want to perform the mod again in the rare case that the 330W died and I had to get a new one.
In order to complete this mod, you will require the following items.
1. Dell 330W PSU (This PSU was built for the M18X and X51 product lines). Part Numbers: Y90RR / 5X3NX / F0K0N / XM3C3 / 331-2429
2. Dell 240W PSU (Either a Flextronix or Delta). Part numbers: PA-9E / J938H / Y044M / U896K / J211H / Y044M
3. Dell or HP standalone PSU cable/Connector. I used a right angle connector but any Dell/HP 7.4 x 5.0mm barrel connector will work.
4. M17x/M18X Power Jack. The part number for this power jack seems to be P01E. Look for the one that resembles the one used here.
5. Small PCB designed for a SOT-23 packaged chip. (If using the Flextronics 240W PSU).
6. Small housing (Optional depending on whether you would like to mod the ferrite choke housing)
PSU DISASSEMBLY
First we begin with the disassembly of the 240W PSU to retrieve the ID chip for our adapter. Since I had the Flextronics version some of these steps might not be the same for the Delta PSU. We start by lifting up the rubber feet on the bottom of the 240W using your nail or a flat tool. Underneath each rubber foot you will find a screw which you can go ahead and unscrew.
One of the screws will be a tamper-resistant Torx T10 type, the difference to a normal Torx T10 being a small pin the centre so you would have to use a Torx screwdriver with a hole in the center.
TIP: If you do not have this tamper-resistant screwdriver you can use a normal Torx T10 screwdriver but you will have to hammer down the pin at the centre of the screw slightly in order to get the normal T10 screwdriver to grip.
Once you have removed all screws you will have to pry open the casing. I stuck a thin knife between the power plug and the casing to gently pry it open.
The top half and bottom half of the casing are held together by interlocking clips. Twist the case a bit to get them to unclip. Then remove the PSU from the case. You will then be presented with the first metal layer which is held on by tape. Cut the tape and slide out the first metal layer.
You will then see the second metal layer which is held in place by 3 points soldered onto the PSU PCB. It is indicated in the picture below. Desolder all 3 points and remove the second metal layer.
The last layer is black and seems to be a type of flexible hard plastic. It will be stuck in place by white thermal stuff on the PCB, simply lift it and peel it away.
Depending on whether you have a Flextronics or Delta PSU your ID chip will look different.
Desolder this chip and keep it in a safe place (If you lose it, you have to buy a new 240W PSU). On the Flextronix PSU the chip is also stuck in place apart from being soldered on, so you have to work quickly heating the solder and pushing the chip away with a bit of force.
To reassemble the PSU reverse the above steps. You can still use this PSU connected to the adapter with your M17X so it won't be collecting dust.
THE ADAPTER MOD
You will have to decide on whether you want to mod the ferrite choke housing into your enclosure or use a dedicated enclosure (small as possible as this circuit is tiny). If you are using a dedicated enclosure jump straight to the labelled wire photo to continue. If you would like to mod the ferrite choke housing continue reading.
I did not take sufficient pictures during this portion as I was unsure if the ferrite choke housing would work. The rubber around the ferrite choke and the connector that I purchased was soft and very flexible which made it easy to work with. I used a knife and pressed against the rubber of the ferrite choke housing for a clean cut so that I could glue it back together. I cut off one end and then length ways along either seam of the housing making sure to leave a bit of extra cable.
Here is a picture of what we’re trying to achieve with the cutting.
You will then see the ferrite choke which you can crack with a hammer. Remove the pieces (be careful as they will be very sharp).
Then the cut off the cable strain relief that's covering the cable with small wire snips.
You will then see the cable which you can strip to positive, negative and the ID line.
You will then need to connect those wires to the power jack. The two pins at the top are negative. The two pins at the back forming the shape of a U are positive and the pin at the back in the centre is the ID line.
Solder the positive wire to positive pin and negative wire to negative pins as shown in the image below. The negative wire can be soldered to the negative pins and simultaneously joining the ID pin on the jack.
The reason behind joining the ID pin to the negative pins on the jack is because we need to ground the ID line coming from the 330W in order for it to operate beyond its artificial 240W limit.
Now all that’s left to do is connect the ID chip. If you have the Flextronics PSU the ID chip will be in a SOT-23 package and the Delta ID chip will be in a TO-92 package. The Flextronics SOT-23 package is difficult to work with and should be first soldered to a bit of PCB that had a SOT-23 package so that you do not break the legs off.
I initially soldered the wires directly to the legs and moving it about in my "enclosure" to find the best spot to place it was too much stress on the chips tiny legs and they broke off... yes, all of them. Luckily I could still see a tiny bit of metal from each of the legs. I managed to salvage it by soldering it to a piece of PCB that I jacked from a broken mouse which had SOT-23 connections.
The blue ID wire coming from the cable needs to be soldered to the data leg of the ID chip. Connect the remaining two pins from the ID Chip together and then to the negative connection on the PSU jack.
Dont judge my pathetic soldering skills!
Place your ID chip into the enclosure and test the adapter to make sure all your connections have proper contact. If it’s working properly you can close it up.
I considered flooding the enclosure with silicone to secure the ID chip and its connections but I did not, as I thought it would be more work if one of the connections broke and I had to open it up again. You can do it if you like.
I used a drill to make the hole at the centre of the disc large enough for the 330W connector tip fit through. I then stuck the enclosure back together using superglue along the sides and then attaching the disc. Add a bit of glue to the disc/jack so that the disc and jack are stuck together as well. This is so that the jack does not move when plugging the PSU connector tip in.
THE COMPLETED MOD
Pros/Cons over the ID Chip swap Mod
Pros
- Allows you to use any PSU irrespective of wattage as long as the connector tip is compatible with the power jack.
- If the 330W PSU dies all you have to do is plug a new one in. No need to perform the mod on a new 330W.
- No need to open up the 330W at all.
- Your ID chip donor 240W PSU can still be used with your M17X by attaching this adapter.
Cons
- Allows you to use any PSU irrespective of wattage as long as the connector tip is compatible with the power jack (Could be dangerous with low wattage PSU's).
- A lot more work compared to swapping the chips.
Notes: I also had to trim a bit of rubber at the right angle connector for the cable I used as it’s a bit of a tight fit if you don't. The rubber around the connector did get a warm at the right angle after testing but it's being blasted by the heat of the CPU fan continuously so I don't think it’s the connector itself that's causing it. These cables are very short and should be able to handle the power easily.
Since there are two positive terminals you will have to either split the positive wire coming from the PSU connector to each pin or join both pins (bend one pin over to the other and solder them together making sure to place an insulator to cover the ID pin) and solder the positive wire to a single point.
Also worth noting is that this adapter mimics the original 240W adapter perfectly. So if you experienced the "plugged in, not charging" issue when connected this adapter will not resolve it (I still have to pop the battery and clip it back in to resolve).
Credits: @imsolidstate, without his in-depth investigation this would have not been possible. His website detailing his investigation and the ID chip transplant can be found here and the subsequent update here.
DISCLAIMER: Perform this modification at your own risk. I take no responsibility for any damage caused by technical error, user inexperience or stupidity.
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