Start out by gathering some:

• Soldering Wire
  
• 2 front Wheels And Tires from ZZMT
  
• Aluminum Tape
  
• Super Glue
  
• Flat-Head Screw Driver (like the one found in your zzmt controller, convenient huh?)

Gather and use the items at your discretion. If you feel you don’t need it, don’t feel obligated to use it.

Get a length of wire about 12 to 15 inches and just lightly straiten it by hand. Don’t stress getting it too strait.

Now start wrapping the wire around the rim from the inside out. By that I mean, start at the part that faces the chassis and work your way out toward the end where the wheel nuts go on. Be sure to get the wire nice and TIGHT!
Loose:

Tight:

Grab that aluminum tape and cut off a strip as thick as your rim and about as long as your circumference. Just be sure that the tape overlaps on itself. Just like I DIDN’T do in the picture. Seriously, do as I say and not as I do.

Using your screw drive, etch out the outline of the wire to make the tape tight.

If you have some tape sticking out over the edge of the inside of the rim, use your screwdriver to push the edge down nice and tight as pictured.

Now you are done. You could stop now, but I’d recommend getting some krazy glue and putting on a thin layer at the previously described “outside” of the rim between the wire and the plastic. Here is your finished product and with a little extra effort, your tires will fit on fine. Try climbing something you knew you flipped on before and be amazed at the difference. Seriously, damn!

So I started looking around the net and here and bookmarking pages that had killer mods that I planned to do (note: I did not find ALL of these, some sites already had lists which I am linking to). Before long I had a good 10 mods, at least. So, to make it easy on all you crawlin’ pimps in the making, and without further adu, here it is:

The End-All, Be-All
ZipZaps Monster Truck (ZZMT) Modification List

Helpful Sites
http://bitpimps.lixlink.com/articles/
http://www.gcrossett.com/zipzaps/index.htm

Articulation
The Articulation Modification - a MUST for any serious crawler!

Gearing
Slow Gearbox Options
Ultra Slow ZipZaps Special Edition (ZZSE) Steering Servo Gearbox

Steering
Hyrdo Style Steering

Tires & Wheels
Weighted Front Tires

Winches (and related)
Winch Pictures
Recovery Points

Cosmetics
Headlights Always On
Magnetic Body Mount

Inspirational Crawlers
RedRustBucket’s FJ40 Landcrusier
Supergroup_Cralwer’s Monster Crawler
Clint’s Halftrack ZZMT
Clint’s Minimalist ZZMT
Biohazard’s Toyota Landcruiser - Scroll down for pics.
Biohazard’s ZZMT Mercedes
Biohazard’s ULTIMATE HUMMER
Smoke&Mirrors’ Black Bear - Sorry guys, had to throw in my own beast! :D

Pimp-tastic Videos

Other Threads Of Interest
ZZ-M And Axle Stall…
ZZMT Crawling - Clod Stall Effect

This is a work in progress, if you feel I left out something important in any category, please PM me in the forums.
Also, I’ve don’t just about every mod on here and would love to answer any questions you have about them.

1. I use Mold Builder by Casting Craft to build my molds there are other Liquid Latex Rubber products out there and can be purchased at any LHS. I apply coats of the Latex to the outside of the item I am going to make a mold of. Make sure they are thin coats as the thicker they are the longer it takes to dry.

If you need to get the mold to dry faster use a heat gun to dry the Liquid Latex Rubber but be careful to close and you can melt the mold or the item your casting.

2. I chose to use the Disney bus as my item to cast. I did not want the Mickey ear windows and some of the bodylines so I covered them with tape so that they did not show up on the final casting. I use waxed paper to set my mold on so that the Latex will not stick to the surface.

3. The mold has now been covered about 6 times always allowing the mold to completely dry before covering it again. Make sure you allow the latex to spread around your item (Bus) so that you have a Flange around the item and something to hold on to. This Flange will support the mold during casting.

4. Now that the exterior mold is finished and has enough layers to make it sturdy during casting you can now coat the inside of the item your going to cast. Repeat the process you did on the exterior just on the inside this will form the inside of the mold.

5. I have turned the outside mold inside out because there are still some bodylines on the windows (Mickey’s ears) in the windows I wish to remove. I take some of the liquid Latex and fill the lines in wiping them clear so they only cover the lines. I repeat if necessary to make sure all the lines are removed I need removed.

6. Now the interior mold is finished. I need to make sure any unwanted material is trimmed off of the mold (inside mold and outside mold) this would be anything I don’t want to show up on the finished cast piece. Also make sure there is no lip around the edges so that when your pour your Epoxy it will flow smoothly.

7. Now to prep the mold if you were to pour now the casting epoxy would stick to the mold making it hard if not imposable to get out. I use mold release agent in spray form to spray on the mold and make it easy to remove the casting once dry. If you spray the mold after use it will also condition it.

8. Now for the casting. I use Easy Cast Clear Casting Epoxy and it comes in two parts. You have a Resin and a Hardener. You mix it 1 to 1 one part hardener to one part Resin. Instead of buying a mixing cup I just use cheap plastic cups and pour one ounce of water at a time to mark the points on the side of the cup. Mix the two parts according to directions (these directions show mixing the two parts for 2 min. putting the mixture into another cup then mixing for 1 Min. longer). Now your are ready to pour the casting.

9. Pour a small amount into the main outside mold then take your inside mold and squeeze it into the outside mold. It will at this point squish the casting Epoxy up to the edge making a thin casting all around. You might have to put a weight on the inside mold to hold it down and in place.

10. Allow the mold to dry for 24 hours you will find with Epoxy the thinner the casting the longer it takes to dry. Make sure you put the mold up so it cannot get damaged or dented.

11. Once it’s dried for 24 hours then remove the inside mold first carefully, if it’s still sticky or real soft allow it to dry longer. The mold even after 24 hours will be soft so handle it gently. Once the inside is removed then gently remove the outside mold and you will have your final cast done.

12. Your final cast will remain soft and easy to bend for at least 48 hours. This is a good thing because you can easily trim any access off the casting and cut out any pieces you wish to remove (wheel wells, windows etc.)

13. Once our cast is completely dry and complete you can sand it, Fill it, prime it and paint it the way you would like.

The type of casting material I use is supposed to release the bubbles as it dries but not all the bubbles will leave the material. I have not found any casting material that the bubbles are not present but this material has the least amount.

Steelwoolghandi

Step 1. At this stage we’ll figure out our colors and materials.

To achieve this pattern and effect two kinds of paints are used from the same manufacturer. For this demo I’m going to use House of Kolor, but this effect can be achieved with Spazsticks line of paints, when using Faskolor (auto air) the candy’s that they sell are semi transparent and do not give you the see through qualities of a good candy. When using faskolor or auto air try doing only the pattern, the semi transparent nature of the paint will muddy the effect. (Always take caution when using urethane paints. That means a good respirator and very good ventilation) it is these opaque and transparent (candy) paints that will achieve the effect of dimension and depth.

The other material used is the free hand shield and the gray scuff it pad (600 grit). The free hand shield can either be bought from your local art supply store or it can be hand made. To make the shield cut out the wheel well of the body and use that scrap piece of lexan as material, draw some flowing random shapes around the wheel well (what ever shapes your in the mood for!). Then with an x-acto knife score around the edges of your markings and snap off the excess, both sides can be used, and the more free hand shields you have the more random your flames will be.

Another small thing that I’ve noticed when doing this technique, is the over spray from the paint, you’ll notice the paint will group together from the static electricity and these will leave odd blotches in your black portions of the paint job, to remedy this I use a tack rag or in a pinch just a paper towel to wipe it all off, just make sure your paint is nice and dry before you wipe it! lol

Step 2. To begin I mask of the windows and scuff the body with the gray scuff pad leaving a dull shine behind me, then I clean it off with a wax and grease remover and its prepped to go. There’s not to much to this first step but remember to scuff, especially with HOK.

Step 3. This is wear we come in with the pagan gold (candy yellow basically) and use this to mark out wear and how far your flames and flame tips will reach, I usually put on a 2 coats of the yellow and try to cover as much as possible in the defined areas.

Step 4. Here is the fun part and the most important as well, the first yellow licks come in. I’ve tried to demonstrate the different kinds of techniques you can use in this picture, I try to use my head a little for filling in things that don’t look right but try not to think about placement or what part of the shield that I’m using. When doing the first fire licks its important to realize that these determine how fare your fire will travel up the sides, I try to keep it to a minimum and go slightly heavy in the front of the fire and try to lighten up as I go back so there’s only a few licks spaced out evenly trailing back. At this point I’ll throw in some free handing to get the licks just right and to give them more of a random flowing look, (see how the free handing works in the pictures below.)

I just come in and take some of the licks back or bring some together and add some streak spots as well. Remember at this stage less is more so be careful, practice really helps this step. Another good tip for this stage is to back the yellow licks with black construction paper to see how they will look. And then you can work from there.

The next pic is of the freehanding i do.

Step 5. After your happy with the small spots of yellow highlights you will come back in with the candy orange, I come in and cover this about an inch or two farther than with the yellow to give myself a good coverage area so the licks that trail off by them selves wont be to bright (just incase.)

Step 6. Here is wear the fire in the background is supposed to come in, to make the effect seamless and blend together you need to either go back in and use your free hand shield or even just free hand in with the light opaque orange (I’m using HOK sunrise pearl in this step, gives the background a little bit of a ghostly shine from the pearl) I’ll free hand in around the edges of the yellow highlights and exaggerate all the curves and licks with the orange, when you go back over the licks it will create the transition from yellow to orange. If you don’t your yellow licks will look like a set of yellow flames over a set of orange flames and they wont blend together. Then after I’ve free handed around the previous licks I’ll take my freehand shield, and start to create more hard edges past the previous yellow/orange licks, then this creates the illusion that the licks cool off as they get farther away from the source. Your just about done so at this stage you can check with a piece of black construction paper how they will look and you can adjust to your taste, b/c this is the last step before you finalize it.

Step 7. Spray in your black basecoat to seal it off from the world. If you want another color as a base you can use red and darker colors that can blend with the candies you used earlier but changing the background color is hard b/c the candies will tint the backer, these flames look best over black its gives them more vibrancy and makes them pop. After you’ve backed it with the black, you can hit it with a sealer for your nitro cars or just something if you’re going to run it. Remove the plastic cover and admire your results. This technique takes practice to be able to get right so try using scrap pieces of lexan or even a sheet of plexi-glass to see how the color react to one another and how the patterns work out. And as always feel more than free to experiment with your own variation of colors and effects, combine this with other effects to get that next new trick!

If you wanted to change it up a little you can use different colors for your flames as well if you do it green try a candy green base coat as your first layer, then back that with an opaque yellow then back that with a candy blue/teal and use green opaque as the final backer. For blue fire use a candy blue as your base, then use a blue tinted white then come back in with a candy purple and back that with the opaque blue. Again you’ll have to experiment with your paint to get a feel for how much of what needs to be put wear.

So thats about it, the secrets out! lol if you need bigger pics or you have more questions my e-mail is extremepaint@hotmail.com

also bigger pics are in my gallery at http://www.cfxpaintworks.com/modules.php?name=coppermine&file=thumbnails&album=4&page=1

Thanks for waiting guys I hope this little how to can get some decent fire jobs out!

For you guys on this board specifically:
If you wonder why i would do this, and I still paint for a living and I know i can make a buck off of ebay, but why you ask? b/c the more people that will push them selfs to paint a body the better it is for airbrushing, and the more people actually trying it the more they will find out its not “that” easy, then they will in turn have a new respect for anyone that airbrushes, if they talk about it (and they will if they tried it!) they will pass that respect and attitude on to the next, their by bolstering the hobby upping the quality complexity and creativity of paint jobs in general. and that just means basically i then force myself to get even better! as well as everyone else and maybe one day it will get to the point of fine art! it takes one step at a time…. the top pro’s in the nation (not “ebay” painters) the guys that have there own shop and advertise nation wide feel the exact same way, well at least the ones that teach. I payed good money to learn how to paint like this (airbrush getaways, dvds, a whole lot of time practicing…. more practice…. and more practicing, talking to people and getting tips from them) and I share it with the rest of you for nothing but to help you guys out…. b/c through that whole jumble of drug induced thought that I just wrote up im helping myself.

Hope those guys that get 100 bucks per dont mind me posting this…. guess the secrets out, gonna have to come up with some new ideas huh!?

Gather up some tools:

• Phillips screw driver
• X-Acto Knife
• Nippy Cutter
• Small files
• CA glue
• Mini hacksaw blade
• Soldering iron
• Needle nose pliers

The nippy cutter. It cuts through plastic like butter and makes this mod very simple. If you dont have one you can make do with a small hacksaw blade and an x-acto knife, but I highly suggest buying one.

(ratshack has them for 5$)

**This is not a tutorial on how to take apart and put together your ZZMT.
If you are not comfortable in doing so, then take some time learning how to do this before attempting the articulation mod. Full Responsibility is yours. I also suggest reading through the tutorial and undestanding each step before proceding as there are many cuts, and a wrong one may send your ZZMT to the scrap heap.

Ok, now take apart your ZZMT.

To remove the on/off switch in one peice cut away at the plastic holding in the wires. You _can_ just desolder it, but soldering it back together in that location is a bit difficult.

Remove the steering gear pins so they dont get in the way.
Just pull them out with some pliers.

Now for some fun, Turn the chassis upside down. We are separating the front from the rest of the chassis. Cut here…

And here…

As you cut through, it should look like this.

Fully separated.

Take the front end and your nippy cutters and trim just behind the ears. You can trim more off it later, it just depends on what body you are going to use.

Now cut this section off the rear off the chassis.

And cut here as well.

Pimp.

Now we trim the rear section, similar to what we did to the front.

Gear side. I keep the arch around the gears, less chance of the batteries making contact with them.

View from above. Leave those mounting holes, we will use them later to mount the PCB.

Now take the bottom plate and cut off the nubs.

Side shot.

If you want to retain the original charging method make it look like this.

If you dont care about the charging terminals, continue to cut away in small segments(the center shaft is fragile), until it looks like this.

Driveshaft section:
This tutorial will cover the hollow tube method. There are other methods.
Take a spare zz antenna.

We want to use the 3rd section, so make the cut on section 2 and section 4 and then push section 3 out through section 4 to separate.

The driveshaft gears can be a PITA to remove without mangling the gears or your hands. :???: But this is a very easy method to get it done. Cover both ends with a few wraps of electrical tape. Twist, and pull. One end will pop off. Yay!

Twist and Pull.

That was easy. No bandaids needed.

Find an xmod wheel spacer, you know one of those really small washers you bought on ebay for 4$ and keep it handy. Mine needed the washer to keep the gears from grinding, yours may not.

Cut the antenna tube so that it’s slightly shorter than the driveshaft and slide it onto the driveshaft.

Shave down this area so that the antenna tube fits snugly within. I had to shave down the top, and insides to allow enough room.

Test fit the driveshaft.
There should be enough room on both ends for the gear stops to sit between the antenna tube and the gears. Here’s a shot of me testing it with the front. You can see there’s still a similar ammount of space at the rear. You can also see the washer, I had to place it between the gear and the rear gear stops.

We are basically done, just put it all back together.
Build the front. Start with the steering.

Steering cover.

Front end all together with the driveshaft.(this could be made into a tutorial on it’s own)

(can you spot the booboo in this pic? two dolla to the first pimp to spot it.) lol

Attach the rear. Make sure it all spins freely, without binding and without gear clicking noise. Dont forget the on/off switch!!!

Now that everything spins ok, glue or tape the driveshaft tube to the bottom plate to keep the front end stable. I taped it as I plan to do more work to this zzmt.

Attach the PCB board using a spare cover screw to one of the mounting holes on the rear chassis. You can wrap some electrical tape to hold the battery in place. Re-solder all of your broken connections. (again this could be a whole nother tutorial, not getting into that here)

Cut the motor clip as the PCB gets in the way of the front tab and install the motor.

Charge and Enjoy!!!

To attach a body, just attach it to the rear clip. Cut off the clip on the front chassis to allow the whole unit to move inside the body.

Depending on your body style, you may have to trim some plastic off of the front chassis. I also add a very small drop of CA glue to the rear clip when attaching the body. This keeps it from falling off and it comes off easily when needed.

2.) Now there should be a piece on the end of the pencil that covers the eraser it looks like this.

3.) Once you have it off you need to take the black tip off it should pop off without alot of struggle. Now you should be holding this.

4.) Here you have to make a choice do you want to solder it of use hot glue i personally feel that the hot glue is more stable and better all around. This is the method i will be using.

5.) Take out your hot glue gun and fill the end with glue let it dry.

6.) Now you need to take out a paperclip and decide where you would like to mount it and what look your going for. a straight exhaust or a drifter style etc. you want to bend the end of the paper clip so you can keep it in place with a screw and bend it the way you want. you can either do this on the body or the chassis determining what look your going for. Here’s 2 examples:

7.) For cars that have a very little space for exhausts on the bumper you might want to trim it a little to make it bigger and let the exhaust flush with the bumper.

8.) Now trim away the excess of the paper clip and take out your exhaust we did earlier and push it on to the end of the paper clip it shouldnt take much force but a little.

Pat yourself on the back you have a to scale perfect exhaust!

1st off, I cannot take credit for this mod. It was either crazydave or DarkTari that inspider me. Can’t be 100% because the insperation came from a bit that they both modded and currently gaces my collection.

OK well the most important thing here is to use the right tools. Of course you could opt for the good old exacto knife, but trust me, your fingers will love you if you use a dremmel. This bit is hands down your best option for this and many other mods.

I, like many other of my fellow pimps use the eyeball method, but if you like you can dust off the old ruler and possibly get better results. So first off I suggest dremmeling out the windows. Don’t go to close to the edge, but get out enough so that later you can clean it all up with an exacto knife. Also, pay close attention to the detail of the car so that you can get a nice relistic look.

Once you have done the 2-4 windows and are comfortable now is the time to take the plunge and hollow out that roof. Get an idea of where the sunroof would normally be and keep in mind that in 1:1 the sunroof needs to go somewhere so don’t make that hole too big. Again just take out what you need to go back in there w/ an exacto knife.

Once all your holes are drilled go in w/ you knife and slowly cut away the excess plastic.

Now go in and clean it all up. Sand lightly w/ smooth sand paper if needed.

Tada that’s about it. I personally like to go all the way and add the black rubber trim to my rides, hence the black paint but there you have it. Your final result could look like this.

This is a great excuse to hack up a beater shell just to get your dremmel skills down. That’s what I did, ooh I should post the pic of that RX7 here, will do that later. :edit: Here she is. Ask any Pimp w/ mad skills, we have all destroyed bits to get to where we are, wether it’s paint, cutting shells or melting down PCBs.

• Summary
• Difficulty Level
• Parts Required
• Tools Required
• Tools Recommended
• Description of Modifications
• Reference Diagrams
• Transistor Replacement
• Resistor Bridging
• Gate Jumper
• Procedure
• Preperation
• Testing
• Disassembly
• Identification of Components
• Removal of Old Components
• Installation of New Components
• Inspection
• Assembly
• Testing
• Parts Sources
• FETMod Service
• Credits

• 2 IRLML2502 (or compatable n-channel SOT-23 MOSFET)
• 2 IRLML6401 (or compatable p-channel SOT-23 MOSFET)

Optionally you may use n-channel devices in place of the p-channel.
Scrap of copper wire.
This is for bridging resistors, an optional step.

• Soldering iron, 15-35Watts, cone tip
• Solder
• Hobby knife or small jewlers screwdriver

• Magnifying lens, hobby clamps or putty
• Small container for parts
• Soldering flux
• Desoldering braid
• Multimeter (Volt-Ohm meter)
• RPM meter

The components are not labeled on the board, refer to this diagram for placment. There may be slight variations from board to board, so you may want to verify connections to other components if your board varies from what you see here.

H-bridge Schematic 1st Generation. Inputs from the controller chip are at the unconnected ends of RSB3, RSB4, RDB3 and RDB4.

H-bridge Schematic 2nd Generation. Same as above, but with the addition of QD5 to control the base of QD1. This is the 2nd generation version of the gate jumper mod, it eliminates the need to perform the gate jumper mod. QD5 is found on the top of the board, near the front on the driver side.

Transistor Replacement
The primary performance improvement provided by the fet mod is achieved by the replacement of the stock transistors with MOSFET devices. MOSFETs allow more power to be delivered to the motors, which increases both torque and maximum speed of the motors. This, in turn, provides more responsive steering and better acceleration and top speed.

Resistor Bridging
There is a total of four resistors that can be modifed to provide a slight performance improvement. RDB1, RDB2, RDB3 and RDB4 are the base resistors for the transistor gates. Their function is to limit the current that flows into the base of each transistor (only a small amount of current is required to saturate, or fully turn on, the transistors. Too much current will damage them. These transistors use a base current of about 1.5mA). Changing them is optional unless the Gate Jumper modification is performed.

The gate of a MOSFET (the equivalent of the base of a transistor) does not draw a significant amount of current, so these resistors can be removed and replaced (or simply bridged) with a bit of wire. This allows the MOSFET to turn on slightly faster, and in the case of QD1 and QD2 allows a slightly higher gate voltage. Bridging only resistors RDB3 and RDB4 will have a minimal effect. RDB3 and RDB4 are series resistors in the MOSFET gate circuit and do not have a significant effect on the operation of the MOSFET. It is recommended that RDB3 and RDB4 are left unbridged.

Resistors RDB1 and RDB2, in addition to their function as current-limiting base resistors, form a voltage divider with the pullup resistors RDP1 and RDP2. This voltage divider results in a very small reduction of the gate voltage supplied to QD1 and QD2. By bridging RDB1 and RDB2 the gate to source voltage (Vgs) can be increased to help the MOSFET process as much power as possible. The voltage divider ratio of 1000:75 means that the maximum increase in gate voltage would be about 7%. I do not currently have performance data from which to make a recomendation on this mod.

The generation 1 schematic shown here has had the four transistor base resistors RDB1, RDB2, RDB3 and RDB4 bridged. It is recommended that only the resistors at the top of the diagram, RDB1 and RDB2, be replaced. There is no significant performance gain from replacing RDB2 and RDB3. The transistors have been replaced with MOSFETs.

Gate Jumper
A significant performance improvement can be obtained on first generation SE’s by jumpering the gate of QD3 to the gate of QD1. The base of QD1 is normally pulled down through QD3, but QD3 is already processing a much larger amount of current from the motor, and so it does not provide as much of a pull-down for the QD1 gate as possible. The gate of QD3 is only active when the car is in reverse, so by jumpering the gate of QD1 to the gate of QD3, QD1 can be kept on except when QD3 is on (p-channel devices are on when the gate is how, n-channel are on when the gate is high). This mod requires that RDB1 be removed rather than bridged. Leaving RDB1 connected or bridge may cause damage to the mosfets.

After performing the gate jumper mod you will probably notice that the motor will give a little surge of power when the car is first turned on. There is a small delay between power-up and the activation of the car’s CPU, during this time the RDP1 pullup is holding QD1 off and QD3 on, which in turn turns on QD2, allowing current flow to the motor. By removing RDP1 this surge can be eliminated.

Since QD1 and QD3 are on opposite sides of the PCB, it is necessary to run a small wire from the front of the board to the back. This can be accomplished by running the wire around the front or side of the board, or a very thin piece of magnet wire (solid copper wire with very thin enamal insulation, usually reddish in color) may be threaded through one of the small holes in the board (these holes are called ‘through plated vias’ and serve to connect traces on one side of the board to traces on the other side).

The vias in the PCB are about 30 guage (0.25mm or so in diameter), and frequently have a bit of solder blocking them. Compressed air or a vacuum desoldering tool will clear them. Desoldering braid my not work well due to the small size, but it can be used to remove most of the solder before using a bit of the magnet wire to clear the hole while the solder is still liquid. Before running the wire through the via it will be necesary to pull the last quarter inch through a piece of very fine sand paper to remove the burrs from the cut end (when clipped the wire is slightly crushed, making it expand sideways to a greater diameter). Thread the wire through the via and cut off the part that sanded portion. Poke the new end into a blob of hot solder on the end of the soldering iron. This should be sufficent to burn off a bit of the enamel insulation and allow for soldering. Do NOT put solder on the via! Use a very small dot of hot glue or epoxy to secure the wire at the via. Epoxy is not recommended because it cannot be removed. If the wire fails the epoxy cannot be removed to make repairs.

The generation 1 schematic shown here has had three of the transistor base resistors RDB2, RDB3 and RDB4 bridged. RDB1 has been removed completely and the gate of QD1 has been bridged to QD3. The transistors have been replaced with MOSFETs.

Testing
Start by testing the performance of your RC car. If you have an RPM meter measure the unloaded acceleration and top speed of the car. You may also time the car over a fixed distance, or measure the maximum incline the car can climb. Select conditions (track surfaces and distances) that can be replicated for comparison testing. Test with a variety of motors if you like. The MOSFET mod seems to perform best with the Radio Shack NOS motor. This motor is fast, but does not exceed the capacity of the batteries to provide power. Faster motors like the King 4.2 also perform very well, but they demand more current than the stock battery can supply. For best performance with very low resistance motors you will need a higher performance battery.

Disassembly
First verify that the car is turned off. Remove the battery as a precaution. Shorting leads while power is applied can destroy components and ruin the car.

Using a small jewelers screwdriver remove the two screws holding the PCB. One is located near the front center of the PCB, the other is at the rear, near where the antenna is connected. Remove the small plastic clip held down by the rear screw and place the screws, clip and black plastic retainer from the front of the PCB and place them in a small container (you may also draw a large diagram of the car and place the parts on the diagram to make replacement very easy).

If the top of the PCB is painted black, it will be necessary to remove some of the paint in order to identify and remove components. Use the jewelers screwdriver to carefully flake off the paint as you work.

To see the bottom of the PCB, carefully lift the PCB off the chassis and note the positions of the wires. When reassembling the car you will want to replace the wires as you found them for the best fit. Flip the PCB over to expose the components on the bottom the board. Use small clamps or putty to secure the board and chassis to the work surface, but be careful not to place too much tension on the wires. Wires pulled off of the board can usually be fixed, but sometimes it can take some very delicate soldering!

Identification of Components
(General Layout)

This is an illistration of the top and bottom of the ZipZap SE PCB. The components are designated using the following naming convention:

• First letter ‘Q’ indicates a transistor
  • Second letter ‘D’ indicates Drive
  • Second letter ‘S’ indicates Steering
• First Letter ‘R’ indicates a resistor
  • Second letter ‘D’ indicates Drive
  • Second letter ‘S’ indicates Steering
• Third letter ‘B’ or ‘P’ indicates a Base or Pullup resistor

This is a first generation schematic of the components and the connections between them. The two h-shaped sections are called h-bridges, the one on the right is for the drive motor, the left is for the steering motor. The inputs to control the motors are at the unconnected ends of RSB3, RSB4, RDB3 and RDB4.

This is a second generation schematic of the SE drive components. Note the inclusion of QD5 near the middle of the diagram.

(Recognizing Transistors)

This is a typical surface mount transistor. At the right side of the image two of the three legs can be seen soldered to the PCB. The third leg is in the center of the opposite side of the device.

(Recognizing Resistors)

This is a typical surface mount resistor. The value of the resistor is printed on the top. The first two digits are the first to digits in the value, the third digit indicates the number of zeros that come after the first two digits. The value of the resistor at the right is 150 Ohms.

(Locating Transistors)
The primary components to be changed are the transistors. On the ZipZap SE PCB half of the transistors (the n-channels) are on the bottom of the board, and half (the p-channels) are on the top. The main drive motor transistors are the four closest to the front of the PCB. The steering motor is controlled by the four transistors located directly to the rear of the drive transistors.

In this image of the bottom of the PCB the n-channel transistors can be seen. The two on the right are the drive transistors. The two on the left are the steering transistors.

These will be replaced with n-channel MOSFETs, such as the IRLML2502s. Some ZipZap SE boards come with one of the n-channel drive transistors (the on in the top right-hand corner of this image, QD4 in the illistration above) double-stacked, it will appear to be twice as tall as the other transistors.

In this image of the top of the PCB the p-channel transistors can be seen. The two at the top (the front of the board when installed in the car) are the drive transistors. The two at the bottom are the steering transistors. Note that the transistor at the lower right is obscured by a black-painted component in this image. This component must be gently bent upward to expose the transistor.

These will be replaced with p-channel MOSFETs, such as the IRLML6401s.

(Locating Resistors)

This is an image of the five resistors on bottom of the PCB that are part of the h-bridges.

The two resistors on the right, RDB3 and RDB4, can be bridged by replacing it with a bit of wire. This is mostly easily done if the resistor is removed first, but this is not necessary for the bridge to work. If the steering transistors are also replaced with MOSFETs the steering base resistors can also be bridged, but it is unlikely that any performance difference will be apparent.

This is an image of the seven resistors on the top of the PCB that are part of the h-bridges.

The two resistors at the top of the image, RDB1 and RDB2, should also be bridged, unless the gate jumper mod (see above) is also performed. If the gate jumper mod is performed, RDB1 must be removed completely and the pads left unjumpered. As above, if the steering is upgraded to MOSFETs, RSB1, the only steering base resistors on the top, can also be bridged (again unless the gate jumper mod is performed on the steering h-bridge, in which case, remove the appropriate resistor).

It is not necessary to modify the pullup resistors. Bridging them will result in a short-circuit when the h-bridge is active, and removing them will leave the MOSFET gates floating, which will probably also result in a short-circuit. The values of the pull-ups can be increased if desired, anything from 3k to 33k would be sufficent. This modification would save a very small amount of power.

(Gate Jumper Leads)

In this image of the top of the PCB, the gate lead of MOSFET QD1 is circled in blue. To perform the gate jumper mod this lead must be connected to the gate lead of MOSFET QD3, seen below. For this mod to work the resistor RDB1 must be removed and left unbridged.

In this image of the bottom of the PCB, the gate lead of MOSFET QD3 is circled in blue.

After the components have been removed, touch the soldering iron to the pads to clean up the solder. If there is more than a very slight lump of solder, use the desoldering braid to remove the extra. There should be just enough solder to hold down the new components that will be placed there.

Here on the top of the board the p-channel transistors for the drive motor have been removed. This is a second generation board, QD5 can be seen at the lower right side of the image. Toward the top of the image the two PNP transistors for the steering motor can be seen.

Here on the bottom of the board the n-channel transistors for the drive motor have been removed. Toward the upper right corner of the image the two NPN transistors for the steering motor can be see, just below the component labeled ‘A3′.

Using a jewelers screwdriver place a small amount of soldering flux on the pads, then place the component on the pads and use the jewelers screwdriver to position it and hold it down. You may also use a bit of contact cement or other adhesive to hold the component in place while soldering. Just be aware that if removal of the component becomes necessary, a permanent adhesive could complicate the operation. Heat one leg of the component to secure it, then proceed to the next leg. If the component is heated excessively allow it to cool a bit before continuing.

Place the new component on top of the small lump of solder left on the pads. No extra solder should be required when installing the components.

Inspection
After all the new components have been installed, use a magnifying lens to carefully inspect all soldering and components. Verify that no solder has formed a ‘bridge’ to adjacent pads, and that all components are properly connected.

Assembly
Reinstall the battery and return the PCB to its original position. Carefully arrange the wires under the board as you observed them when removing the PCB. Reinstall the front and rear PCB clips, and don’t forget to thread the antenna back through the strain-relief in the rear clip. Do not over-tighten the screws, the plastic strips easily and can be difficult to repair.

This is the top of a finished first generation board with a double stack of p-channel MOSFETs and bridged resistors.

This is the bottom of a finished first generation board with a double stack of n-channel MOSFETs and bridged resistors.

Testing
Refer to the notes taken during inital testing and retest the vehicles performance under the same conditions. By compairing results you will get a quantitive assessment of the performance improvement, rather than error-prone and subjective qualitive assessments (i.e. ‘it feels twice as fast!’ ).

Materials:

• Soldering Iron
• Exacto knife or dremel (preferably exacto knife, as your product will be cleaner in the end)
• Hot Glue gun (optional)

1. Disassemble the stock controller, and cut off the charging pad’s wires at the board.

2. Solder on your charger’s matching plug. You should now be here:

3. Now, you’ll need to make a hole somewhere in the controller to run the plug out. I personally discarded the wristband attachment, and made a wire hole. The dremel works, but the plastic on my ZZ controller is so soft it’d massacre it, so the exacto knife is the tool of choice. Pic:

4. Now, if you went the way out like I did, you can just glue the plug down right there, or you can let the wire come all the way out. Either way, make sure the wires are running out in that notch you made. Put the controller back together and it’s done.

Here’s my finished product:

And hooked up to my Apache S2500:

Easy, eh?

The board reduces the power of the first step, to provide better low-speed control of the car when using very fast motors, and raises the output of the last two steps to 75 and 100% to provide roughly 50% more power to the motor for high speed operation.

The DC mod provides a performance increase of about 30 to 60% without the need for replacing the drive transistors with MOSFETs. However, MOSFETs still can provide a performance increase. The DC mod works with or without MOSFETs.

• 1 DC mod board
• 1 150 ohm resistor (if installing on a car that is not FET modded)

• Soldering iron, 15-35Watts, cone tip
• Solder
• Hobby knife or small jewlers screwdriver

• Magnifying lens, hobby clamps or putty
• Small container for parts
• Soldering flux
• Desoldering braid
• Multimeter (Volt-Ohm meter)
• RPM meter

The components are not labeled on the board, refer to this diagram for placment. There may be slight variations from board to board, so you may want to verify connections to other components if your board varies from what you see here.

This is an illistration of the top and bottom of the ZipZap SE PCB. The components are designated using the following naming convention:
Description of Modifications
Reference Diagrams
You may refer to the following diagrams for component naming and locations on the PCB.

The components are not labeled on the board, refer to this diagram for placment. There may be slight variations from board to board, so you may want to verify connections to other components if your board varies from what you see here.

This is an illistration of the top and bottom of the ZipZap SE PCB. The components are designated using the following naming convention:

• First letter ‘Q’ indicates a transistor
  • Second letter ‘D’ indicates Drive
  • Second letter ‘S’ indicates Steering
• First Letter ‘R’ indicates a resistor
  • Second letter ‘D’ indicates Drive
  • Second letter ‘S’ indicates Steering
  • Third letter ‘B’ or ‘P’ indicates a Base or Pullup resistor

H-bridge Schematic 1st Generation. Inputs from the controller chip are at the unconnected ends of RSB3, RSB4, RDB3 and RDB4.

H-bridge Schematic 2nd and 3rd Generation. Same as above, but with the addition of QD5 to control the base of QD1.

This diagram shows three examples of the input to the DC mod chip next to the output generated for that input. The duration of the input pulse is measured, and as soon as it stops the output pulse begins. The length of the output pulse is determined by a lookup table in the mod chip.

In the third example the top waveform represents the maximum output generated by the third generation of the ZZSE, a 56% duty cycle (a 5.6mS output pulse with a 10mS cycle time). The lower waveform is the 100% duty cycle the DC mod board generates.

Testing
Start by testing the performance of your RC car. If you have an RPM meter measure the unloaded acceleration and top speed of the car. You may also time the car over a fixed distance, or measure the maximum incline the car can climb. Select conditions (track surfaces and distances) that can be replicated for comparison testing. Test with a variety of motors if you like.

Disassembly
First verify that the car is turned off. Remove the battery as a precaution. Shorting leads while power is applied can destroy components and ruin the car.

Using a small jewelers screwdriver remove the two screws holding the PCB. One is located near the front center of the PCB, the other is at the rear, near where the antenna is connected. Remove the small plastic clip held down by the rear screw and place the screws, clip and black plastic retainer from the front of the PCB and place them in a small container (you may also draw a large diagram of the car and place the parts on the diagram to make replacement very easy).

To see the bottom of the PCB, carefully lift the PCB off the chassis and note the positions of the wires. When reassembling the car you will want to replace the wires as you found them for the best fit. Flip the PCB over to expose the components on the bottom the board. Use small clamps or putty to secure the board and chassis to the work surface, but be careful not to place too much tension on the wires. Wires pulled off of the board can usually be fixed, but sometimes it can take some very delicate soldering!

This is a typical surface mount transistor. At the right side of the image two of the three legs can be seen soldered to the PCB. The third leg is in the center of the opposite side of the device.

Recognizing Resistors:

This is a typical surface mount resistor. The value of the resistor is printed on the top. The first two digits are the first to digits in the value, the third digit indicates the number of zeros that come after the first two digits. The value of the resistor at the right is 150 Ohms.

Connections:
If the DC mod board is to be installed on a car without the MOSFET mod the output to the H-bridge must go through a 150 ohm resistor. This is to limit the current supplied to the base of the transistor. The surface mount resistor RDB4 may be used for this purpose, or a new resistor may be supplied. Any sise resistor will serve, but for space conservation the smallest available should be used.

The DC board requires four connections, power, ground, input from the ZipZap CPU and output to the H-bridge.

The input and output connections must go to the bottom of the board, the power supply leads can go to the top or bottom. As show nere the power supply leads have been attached to suitable ground and power connections on the bottom. The board may be powered directly from the battery or from the 3v booster on the SE. Here it is connected directly to the switched battery positive input to the PCB.

Inspection
After all the new components have been installed, use a magnifying lens to carefully inspect all soldering and components. Verify that no solder has formed a ‘bridge’ to adjacent pads, and that all components are properly connected.

Assembly
Reinstall the battery and return the PCB to its original position. Carefully arrange the wires under the board as you observed them when removing the PCB. Reinstall the front and rear PCB clips, and don’t forget to thread the antenna back through the strain-relief in the rear clip. Do not over-tighten the screws, the plastic strips easily and can be difficult to repair.

This is the reassembled car with the mod board installed above the motor clip. This seems to be a good location for most body tops, but the board can be installed anywhere it fits. If the motor is to be changed frequently a different location might be prefered.

Testing
Refer to the notes taken during inital testing and retest the vehicles performance under the same conditions. By compairing results you will get a quantitive assessment of the performance improvement, rather than error-prone and subjective qualitive assessments (i.e. ‘it feels twice as fast!’ ).