Upgrading a HL Pz. III to Full S&S With IR Capability and Metal Track & Gears
« on: December 20, 2009, 03:48:20 AM » - Repost from the old Hobby Havoc Site
With the release of Heng Long’s RX-18 control board infrared battle capability for Heng Long tanks became easily affordable upgrade option. The RX-18’s easy plug configuration makes any such upgrade appear at first glance to be quite straight forward. However, the process of upgrading tanks to full IR capability isn’t quite as simple as it should be and the lack of documentation only make the process more challenging for the first timer. With this in mind I though a comprehensive upgrade guide could be beneficial to many tankers. Consequently, I have tried to document here a complete upgrade process for a NON smoke & sound Heng Long Panzer III to a full smoke & sound tank with metal gears and IR battle capability. The airsoft gun will be consigned to the bin and a more realistic scale barrel will be used.
Anyone who upgrades a tank is unlikely to stop at just an upgrade of the internal electrics without any corrections or modifications to the exterior of the tank. Once the upgrade to IR capability has been completed the second part of this guide will look at some corrections and modifications of a stock Heng Long Pz III. This project will turn the bog standard grey Heng Long Pz III pictured below…
into…..THIS …a Panzer III Ausf. L of the Pz. Abt 502 Leningrad, 1942
PART ONE FULL RX-18 UPGRADE with METAL GEARBOX
There are two sections to Part One, one section devoted to the hull and the other to the turret or more specifically the main gun. Each section can be worked on first but to work on the turret first you will need to complete Steps 1 and 2 of Section 1 which deal with separating the top deck and turret from the lower hull.
Section 1. HULL BASIC
Step 1. Separate the hull from the top deck & turret
Turn the tank over and remove the seven screws holding the top deck & turret.
Step 2. Disconnect 8-Pin & Aerial connectors
To fully separate the two halves of the tank disconnect both the 8-pin & aerial connectors. If you wish to work on the turret first then you can now jump to Section 2.
Step 3. Remove Control Board, Motors & On/Off Switch
Each motor and gearbox assembly is secured to the hull with 3 screws. Remove all of these screws. The motors driveshafts are also connected to the drive sprockets so the screws attaching these will also have to be removed and the drive sprockets gently pulled off the shafts. This can be done without removing the tracks. Once the drive sprockets have been detached remove the RHS motor by pulling the motor up and forward (rotating about the driveshaft) to free the gearbox from the positioning pins underneath. Repeat for the LHS motor.
The control board is secured by three screws, one easily located in the middle of the hull, the upper screw is slightly obscured by the tracks and the bottom screw is located near the suspension arms. None of these screws are particularly hard to get to and the board can be removed with out any disassembly of the suspension system. Underneath the control board is the on/off switch. Remove the small mounting screws holding the switch in place. Finally cut the wires from the battery to the switch as close to the switch as possible. All the internal components can now be removed from the hull.
Step 4. Replace Motors
If your new motors with metal gearboxes do not have the 2-pin wire connectors already attached you will need to do so yourself.
For each motor the BLACK wire connects to the tab nearest the 3 openings in the motor case. The RED wire should connect to the solder tab closest to the single opening in the motor case. (The OPPOSITE as shown below)
Installation of the motors is best done as a reverse of how they were removed. Starting with the left had side motor at about 45° to the hull insert the drive shaft then rotate the motor down onto the positioning pins. Fix in place with the three screws and repeat for the right hand side motor.
Once the motors are in place the drive sprockets can be re-attached to the drive shafts. As stated before the whole process of gearbox replacement can be done without removing the tracks or any of the road wheels
Step 5. Rewire On/Off Switch
The power switch for most Heng Long tanks is actually double pole switch. If you cut the wires from the switch, fire up your soldering iron and remove all the excess solder you will probably find that you have 6 contacts on the switch rather than 3. If so connect the wires from your battery to the middle pair of contacts. Connect a 2-pin connector to a pair of outer contacts. This 2-pin connector will supply the power to the RX-18 board.
(NOTE: Kamaz has suggested an alternate means of re-wiring this switch in his post )
Step 6. Insert Receiver Board & Speaker
Unsolder or cut the aerial connecting wire from the old control board and solder into position as shown below on your new TK-YL101 receiver board. For added strength add a bit of hot glue around the base of the wire. Insert a receiver crystal, connect a 3-pin wire connector and secure the receiver board in place with 3 screws. Place the Heng Long speaker into position towards the left rear of the hull and secure in place with the three screws used to mount the old control board.
Step 7. Wire the Volume Control
The wiring of the volume control is one of the two issues that cause the most concern in an upgrade to the RX-18 board. If you are upgrading an existing smoke & sound tank then you will already have a suitable volume potentiometer. However it will need to be re-wired. The easiest way to do this is to buy an additional 3 pin - 3 pin bridge cable. Cut off one of the connectors and solder the three wires to the back of the volume control board as per the figure below.
In this particular case a NON- smoke & sound unit is being upgraded so a new volume control is needed. The volume control itself is simply a 10k trimpot. Most trimpots have a pretty standard pin out arrangement. The green wire goes to pin 1, yellow to pin 2 and the blue wire to pin 3 (see below)
(Note: I happened to have a spare Heng Long Volume control board and have used it for the first stages of this upgrade project.)
Step 8. Secure Volume Control & On/Off Switch
For this stage secure the switch and volume control in position on the hull floor. Eventually the on/off switch and volume control will be moved to a more accessible location. Make flush the four protruding squares on the top of the battery compartment.
Step 9. Attach the RX-18 and Associated Wires
Cut 2 x 5 mm lengths of double sided foam tape place on the underside of the RX unit and mount as shown. If you plan to keep the airsoft unit then you cannot mount the RX unit in this location. It will need to be mounted on the side where the old control board was located.
Step 10. Install the Smoke Unit and Attach Wires
The Heng Long smoke unit attaches to the rear of the hull and is secured again by three screws through the bottom of the hull. Now is as good a time as any to start connecting all the wires to the RX-18 board.
Step 11. Wire Smoke Unit On/Off Switch
A switch must now be wired in to turn on and off the smoke unit. Any simple switch will do but to save costs I reuse the Heng Long switch that turns on or off the airsoft gun. Removal of this switch is covered in Section 2 Turret Basic.
Step 12. Construct Internal Aerial & Mount Smoke Unit Switch
At this point a decision should be made as whether to keep the supplied aerial or install an internal one. If you plan to keep the original one then there is no need to change the original aerial connector. If you want to install an internal aerial then there are a few ways to do it. The first thing you will need is some wire, in particular enamel copper wire which is suitable for winding chokes, crossover coils etc. This wire has an enamel coating which acts as an insulator (something that needs to be remembered when soldering). I have chosen to use 0.63mm (22swg) wire from Jaycar Electronics (WW4018). It comes in a 36 m roll at about $10. Expensive for a single aerial yes but only 331 mm is needed per aerial. One roll can produce over 100 aerials (true cost 10 cents each). Once you have cut 331 mm of wire it can then be wrapped around a short length of plastic/styrene tubing which is then placed inside the hull. Many users have had no problems with this type of aerial. However, I have. had much better results by bending the wire into an S-shape for Panzer IIIs & IVs or a U-shape for Tigers and hot gluing across the rear of the hull. In the case of the Panzer III I drill a series of holes in the rear hull attachment and thread the wire through into the shape of an S (see below). I then snip off the other half of the old aerial connector wire connected to the old aerial and solder this to the new aerial. (NOTE: Even though it doesn’t look like the aerial wire is insulated. Remove a few mms of insulation with some sandpaper or file BEFORE attempting to solder.)
The rear hull attachment also provides a great space to locate the smoke unit switch. Cut a 22 x15 mm piece of styrene (at least 3 mm thick) and in turn cut an opening for your switch.
Step 13 TEST
The tank is now ready for the first test of your RX-18 installation. Make sure that you have a new smoke & sound transmitter unit and that it is fitted with a matching transmitter crystal. Turn on the transmitter, turn on the tank, rotate the volume control to half way and press the start button on the transmitter. If all goes well you should hear the engine start up sound. If not maybe the on/off switch is back to front, flick to the other position and try startup again. If the tank runs backwards instead of forwards then your left and right motors are connected to the RX-18 the wrong way around, simply swap them over. Make sure to test the smoke unit switch as well.
OH YEAH ..... I FORGOT
If you are upgrading from a NON smoke & sound unit then you will need to get a new transmitter and a pair of matching crystals before you will be able to test your installation. The RX crystal pops into the two big holes on your TK-YL101 board and the TX crystal into the front of your new transmitter.
COMING UP NEXT SECTION 2. THE TURRET ....Statistics: Posted by Phyrephish — Mon May 23, 2011 4:54 pm
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