I'm hoping that this tutorial will save some people a little money and me a lot of work. Here is how to install my H-bridge.....please do not attempt it unless you read and thoroughly understand these directions. It wouldn't help to ask me about something that is unclear as well. Just be sure of yourself and your skills. I don't want to be held responsible for someone biting off more then they can chew. So here we go.....
To desolder FET's/Install H-bridge you will need the following tools:
* soldering iron
* solder
* copper desoldering braid
* small precision screwdriver or something of the like
* black electrical tape
* digital multimeter
* skills
Optional and useful:
* "Third-hand" alligator clip stand
* Liquid flux
* static mat w/strap
Take your xmod completely apart, or as much as needed to get the EP completely out. Your motor FET's will need to be desoldered and removed to apply this modification. To do this you'll need to carefully remove solder in a series of "remove then cool" type procedures until the solder is stripped enough to attempt the FET removal.
The "remove then cool" procedure, for lack of better words, is a procedure which you place the copper braid over the area to be desoldered, apply heat to the braid for a matter of 3-5 seconds, then remove heat AND the braid at the same time, then you let the area cool for about 10 to 15 seconds.
This procedure is repeated as many times as it takes until the solder is virtually gone from the FET/PCB pad joining. If you happen to have liquid flux, you can speed the procedure up a tad by using a drop of it to quickly cool off the desoldering area, in which case you wouldn't need to wait the 10-15 seconds in between desoldering attempts. If you don't have liquid flux, then don't worry about it, you'll just have to be more mindful of your heating time and cooling time. Be very careful of the tiny transistor that is near the legs of the FET's. It is crucial that you don't burn, destroy, or remove that transistor. Once you have adequately removed the solder from all of the legs of your FET's, they should look like this, and should be ready to "heat and pry" them off.
This is where the small screwdriver comes in. Apply the heat to all 4 pins of one side of the FET's, and very gently pry up the side of the FET.
If you've removed enough solder and apply heat just right, the FET should lift right up. It is crucial that you don't force the legs too much, because you can rip the pads right off the xmod PCB, in which case you've opened a whole new can of worms. We'll just hope you don't do that. Once you removed both FET's, your xmod PCB should look like this.
You are now ready to solder the 4 wire signal strand to the xmod PCB.
To solder the 4 wire strand to the xmod PCB, it is very helpful to have a third-hand alligator clip stand. You can have one clip hold the EP, and have the other hold the wire in place, while you solder the wire to the pads.
You should strip a very small portion of insulation off of the ends of the 4-wire strand, that was included in the kit. Then pre-tin each wire end, for a quicker joining and cleaner result. Look up "Tinning" on the internet if you don't know what it is. Solder the wires, in order, from left to right so that they will fit nicely under the EP inside the chassis.
The order from left to right on the xmod PCB is not going to be the same order that they are soldered on the H-bridge, however. We'll deal with that later though. To distinguish the wiring, I found it helpful to put a stripe along the the two wires which go to IC5, with a black marker.
