File: D:/web/homefly/reference/Combo Rx.htm
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<title>Coural 900mg Combo Receiver</title>
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<b>MPS 1.3mg Combo Rx V2.0</b>
<p>Description: Narrowband FM receiver with 2 actuator functions and ESC<br>
Crystal: standard GWS-type 455kHz IF<br>
Switching frequency: 4kHz (ESC and actuators) <br>
Resolution: 50 steps (ESC and actuators)<br>
Actuator current: 0.5A continuous, 1.5A pulsed<br>
Recommended actuators: 30<font face="GreekC">W</font> to 200<font face="GreekC">W</font><br>
ESC current: 3.2A max (no BEC) <br>
Tx signal: FM PPM negative or positive shift<br>
Supply voltage: 3.5V to 4.2V<br>
Selectivity: <10kHz channel separation<br>
Range: 150m ground, 300m air<br>
Power connector: 2-pin 0.1" inline socket strip </p>
<p><br>
If the actuators move the wrong way, reverse the wires to the + and - outputs
or move the servo-reversing switch on your transmitter.</p>
<p> The power supply wires carry 0.5A to 1A pulses. The receiver is supplied with
28 AWG wires (0.35mm diameter). The insulation on these wires is heavy and 28
AWG enamel-coated wire (magnet wire) could be used instead. <br>
The motor uses most of the current supplied by the receiver. It should be wired
using 28 AWG stranded or enamel-coated wire as well. For the actuators, we recommend
36 AWG wire (0.7mm diameter). </p>
<p><b>Soldering Hints </b><br>
To solder enamel-coated wires, it is necessary to first remove the enamel and
tin the copper underneath with solder. Fortunately, the enamel is designed to
burn off cleanly at normal soldering iron temperature.<br>
Don't try to scrape the enamel off with a blade as you will likely nick or cut
the wire. Instead, apply a soldering iron and solder to the end of the wire
until a bead of solder forms around the wire. You must keep the wire and the
soldering iron in this bead for at least 30 seconds to give the enamel time
to burn clean and allow the copper to become completely tinned.<br>
Another way is to put a large bead of solder on the tip of your iron. Under
magnifying glass put the wire into the drop with an in-and-out movement. Add
new solder as soon as too much garbage is visible. If the end of the wire is
not completely immersed in the drop, or if the iron is not hot enough, the wire
will not become tinned.<br>
To solder wires to the combo, add a small amount of solder to the pad and heat
with the soldering iron until the solder flows out smoothly. Now put the wire
onto the pad until the solder covers it smoothly as well. Never try to solder
an un-tinned wire directly to the pad.<br>
To solder 2 enamel wires together, it is best to twist the wires together (enamel
and all), and then apply solder and iron to the joint for 30 seconds until the
solder flows smoothly onto the joint. A smaller joint can be accomplished by
aligning the two wires on an aluminium plate and working them patiently with
a soldering iron until a suitable joint is obtained.</p>
<p><b>Interference</b><br>
Route the antenna wire as far from the other wires as possible. Make all wire
connections as short and straight as possible. Try and minimise crossovers and
loops in the wires as well.<br>
<b>Bad motor</b>: Out of 20 M2VA motors I have used, one in particular generated
unsolvable glitches. This was likely due to faulty brushes and the motor was
promptly disposed of. You have to think about this because a defective motor
is possible. Some gearboxes have a metal rod turning in a brass bearing: prefer
a carbon rod with micro ball bearings instead.<br>
<b>Interference with motor stopped: </b>Problem with the antenna or receiver
not tuned correctly.<br>
<b>Interference with motor running:</b> Antenna wire too close to motor wires.
Receiver not tuned properly. Insufficient noise-suppression capacitors. For
the M2VA motor, I use a 47nF capacitor between the plus and minus terminals.
If needed you can add 2 caps: one between the plus terminal and motor case and
another between the minus terminal and motor case. For pager motors, ceramic
capacitors between 50nF and 100nF are sufficient.<br>
Sometimes, moving the receiver 90° solves all the problems.</p>
<p>If you have glitches on the 2 actuators, this is probably HF interference from
the motor. If only one actuator has glitches, there are two possibilities:<br>
1. The ESC mosfet can radiate through the thin board (rare). Re-soldering it
vertically solves the problem.<br>
2. Some transmitters can have a function (throttle) generating commands on the
adjacent channel (rudder) due to stick potentiometer problem: this is totally
solved in software by enlarging the dead band.</p>
<p><b>In-flight Interference</b><br>
Metallic structures in the airspace. You are flying with transmitters on nearby
channels.</p>
<p><b>The receiver doesn't respond</b><br>
Receiver not tuned. Antenna unsoldered. Reversal of the power supply polarity
(disconnect quickly!)</p>
<p><b>Tuning the receiver</b><br>
The tiny screw near the SMD crystal can tune the receiver to the transmitter
frequency. <br>
If the combo is working correctly, never touch this screw!<br>
The receiver is sold pre-tuned to the transmitter frequency. With some inexpensive
transmitters, tuning can be imperfect. With this screw, the combo can be re-tuned.
You need a micro screwdriver and one actuator connected to the combo. Check
the existing position of the screw and mark it with felt-tip -- the optimal
position is not very far from this point.<br>
Disconnect the power supply and turn the screw from 0.5 to 1° to the right
or the left.<br>
Power up the combo again and if the servo is working, you're done. Otherwise
repeat the last two steps until you find a good position. This is generally
found no more than 3° right or left from the initial position.<br>
If the actuator works, circle the receiver with the transmitter at 2m or 3m
distance. You must not have interference. Otherwise try to adjust again the
screw. Don't put the transmitter too close to the combo as this generates signal
distortion. Once good tuning is achieved, you should never have to adjust it
again.</p>
<p><b>Power supply</b><br>
The combo is designed to work with one Li-Poly cell, so 3.5V to 4.2V is the
best zone. <br>
</p>
<p><b>Programmable transmitters</b><br>
The receiver's microcontroller calibrates the ESC and magnetic actuator channels
each time it is powered on. You must always turn on the transmitter first, servo
sticks at neutral and throttle off. Then connect the combo without hesitation.
You can trim around the neutral if you want but memory of the trims will not
be recorded when you disconnect the combo. To do this you must have an extra
switch on your programmable transmitter. Always turn the receiver off first,
then the transmitter.<br>
Trying to trim over the maximal position has no effect: you will have no extra
power and you risk creating problems. Don't try to put some functions at 110%
to get more power. Square signals over 2ms or under 1ms are seen as a glitch
by the software and are rejected. The consequence can be "no rudder"
when motor is at full power. Generally, the microcontroller will calculate the
best configuration for you automatically.</p>
<p><b>Manufacturer</b>: <br>
Micro Planes Solutions<br>
www.microplanesolution.com<br>
jlcrl@club-internet.fr</p>
<p>Jean Louis Coural<br>
1 rue de cruscades<br>
11200 Villedaigne<br>
France<br>
(33) 04 68 43 80 12</p>
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