Rx66a Overview



6A Heatsink

Blade Tx

Blade Tx



PCB ID: 66a
PCB SIZE: 26x46mm (1.1x1.8")


2.4GHz receiver compatible with DSM2/DSMX including one integrated 4A reversable controller for brushed motors (ESC).
The current rating can be increased with a suitable heatsink.
3-18v for 1-4S lipo, 1-5 life, 3-12 nicads, 1 PP3

Click to
Name GBP H



Instructions (x=Variant 1-22)

(4A current)

(U=with long aerial)



1 8 3 x = 1, 2, 22, 3, 4, 6

(6A current)

(U=with long aerial)
(H6=with 6A heatsink)



1 8 3 x = 1, 2, 22, 3, 4, 6

eg: Rx66-2 (Variant 2)
eg: Rx66-22 (Variant 22)
eg: Rx66-22-U (Variant 22 with long aerial)
eg: Rx66-22-H6 (Variant 22 with 6A heatsink)
eg: Rx66-22-H6U (with 6A heatsink and long aerial)


Rx66-1: Settings for 'trains' with separate controls for speed and direction

Rx66-2: As above but one control for throttle (center off)

Rx66-22: As above but with Selecta enabled (for use with Tx22)

Rx66-3: Mostly servo outputs

Rx66-4: Settings for 'cars' (like Rx43d-1)

Rx66-6: Settings for 'cars' (like Rx43d-6)


The simplest way to start is with a 'wired' version of the receiver (eg: Rx66-22 with Tx22-Built). Connect the red/back to a battery and two other wires to the motor, bind once and that's about it. If you use a 9v battery in the train you normally have to disable LVC. Make sure you read the instructions for your variant (links above).

'Variants' are simply 'configurations'. Each variant is a different combination of settings to better match common needs. Although these are described as 'car/train/boat' any variant can be used for anything. All settings can be changed in a process called 'programming'. F1-F3 (A/B/C) are programmed as P9-P11.

More advanced info:
The receiver is built with 20v components and is rated for 3-18v operation.

'P' outputs are 'pads' with 'logic' type outputs. Pads are simply solder points for controlling external things. Logic outputs are either on or off (also known as high/low and 3.3v/0v in voltage terms). The action can be inverted so 'On' can mean 0v. P outputs are used to provide servo signals direct to the white/yellow lead on a servo. They can often directly control triggers on external sound cards. They are also used to drive leds but need a resistor to limit current to no more than 20mA.

'F' outputs are 'buffered' P outputs. The buffer is an N-channel fet. These provide a path to ground (0v) when on and are floating (disconnected) when off. If you are familiar with the term 'open collector' used with transistors, these are the same but with fets they are called 'open drain'. Three F outputs exist on Rx66. They are labelled A, B and C. They are often used to control sound cards and lights.

The 'H' output is an H-Bridge. This is used to control the speed and direction of a brushed motor. This can also be referred to as an integrated ESC (Electronic Speed Controller). It has 256 step resolution in both directions (512 total). It controls speed with PWM which by default is set to its fastest (quietest) 16kHz setting.

The H output on the base product is rated at 4A current max. This is measured with motor stalled. The main constraint with current is heat. Higher currents are possible with a heat sink. The 'H6' heat sink increases current rating to 6A. This heatsink has a 17'C/W thermal resistance rating. Higher currents are possible with heatsinks that have lower thermal resistance or with a fan. Temperature rise of the product should be limited to 20'C above ambient. Thermal runaway is a risk when the product exceeds 50'C. Thin wire generates heat so the thicker the motor and battery wires the better.

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