sky-star-tx-9009-helicopter

Tian Xiang helicopter – 9009 RC Aeronef

Preamble

From Din Daeng market I found a  TX9000 RC helicopter – 60 Baht the helicopter, 20 Baht for the controller. It was missing the charger and a blade is cracked. Two days later I went back and managed to get the correct charger (4V, 650mA) for 10 baht. I also obtained a second broken helicopter for parts, a week later.

Video

A great unboxing and demonstration video

In the video above, the remote is slightly different from the one that I have. The logo is the same, however the thrust does not seem to be spring loaded to remain in the off position when not being held –  that is to say, it appears to be free and remains in whatever position it was put into. The following video shows a controller with the same thrust control as the one that I have, so that when no pressure is applied, the thrust is “off” and the lever is in the down position.

Also, it should be noted (from both of the videos) that the charger, while it has a red light when it is plugged in to the power supply, when it is then connected to the helicopter, so as to charge the helicopter’s LiPo battery, the red LED goes off. Slightly disconcerting, but presumably this is as designed. Upon consulting the manual, it is stated that the charger’s LED remains off until the LiPo is sufficiently charged. When the LiPo is fully charged, then the charger’s LED will light up. Also, charging time should not exceed 100-110 minutes. After waiting, an anxious couple of hours, the red LED on the charger did indeed light, indicating that the LiPo was charged.

Unfortunately, my controller, when I put some new AA batteries in it, does not appear to switch on. That is to say, when the switch is slid to the ON position, the red LED does not come on.

Investigation of the controller

Dismantling the controller is simple enough.

Optional – The batteries and cover can be left in place. Remove the screw retaining the battery cover and the battery cover itself – the  batteries can be left in place, although it is probably better to remove them.

Remove the two small screws in the rear of the handle and then the remaining four larger screws in the rear of the body.

It is necessary to remove the left hand thrust lever with a stiff tug, once the two halves of the case are loose. Alternatively, remove the tiny screw inside the shaft of the lever, and remove the lever handle, leaving the red dome in place, on the spring loaded switch.

The two trim buttons will probably come loose, of their own accord, and fall out. No need to worry, as they can only fit into the front half of the case in one orientation, and so it is easy enough to reassemble. The right hand lever can be left in-situ, on the PCB.

Inside the RC controller
Inside the RC controller

Removing the two retaining screws holding the PCB allows access to the rear of the PCB, although care must be taken not to strain, or break, the thin power wires. It is best to flip, or lean, the PCB back using the rear of the battery compartment as a virtual hinge.

The reverse side of the PCB
The reverse side of the PCB

No burning was visible, and when checked with a multimeter, power was seen to be going to the board.

Reassembly

Upon re-assembly, take care with the LED to ensure that it does not get bent, which will happen, if it is misaligned with the hole in the front of the case.

If you removed the entire left hand lever, including the dome, then gently push it back on, with the lever in the down, or off, position.

Now, turn the control over, so that it is upside down, and ensuring that the left hand lever is not strained, open the right hand side of the case, sufficiently, to allow access to the holes where the trim buttons should be. Now, place, or drop, the trim buttons into their respective holes, whilst holding the front of the case upside down and then, gently, place the rear of the case, containing the PCB on to the front of the case (taking care to align the LED with its hole, as stated above).

Status LED

The red LED on the controller appears to have various modes, as can be seen in the video:

  • Flashing – searching for a pair
  • Steady – when the controller is paired with the helicopter’s control board

However, these are not covered in the manual.

It could have something to do with the calibration. From galvanic Rc Helicopter – Mawa010B2 – First Flight recapitulate

When you turn on the remote the very first time. Turn on the helicopter first and the red light will light up, which is kind of cool at night, it lights up the front of the copter, which on my red helicopter looked good. But then when that is on, turn on your remote with the switch. The red light will flash, then it is off again. gradually push the throttle all the way up once, you’ll notice it won’t turn on the helicopter yet. At the very top, full throttle (the left trigger), the light will blink certainly fast, then lower the throttle all the way down to the very bottom, and the light will stay on all the way, and then blink slower after a minute. Now you are calibrated and ready to fly.

In the video, you will notice that the throttle is at max, with the LED flashing, until the throttle is brought down to off and then the LED remains steady.

Links

From google

See also

Further Reading

As a spin off, I was interested to know what the 14 pin IC was, which is used in the controller. It has no writing etched upon it, only a sticker labelled 40M. I thought that it would, probably, be a variant of the TX2B/TX2C.

On the transmitter, the anode of the LED is connected to pin 8 of the IC via a 1k resistor. However, pin 8 (SO), of these two variants, would not appear to be connected to an LED if you examine example circuits, like this one from 5 channel radio remote control:

5 channel radio remote control circuit
5 channel radio remote control circuit

 

Besides the transmitter for the TX 9009 is a 3 channel transmitter, and the TX2B is a 5 channel IC.

Anyway, I found these two links useful:

The circuit

IC pinout

  1. R1 (R1-> GND), R2 (R2-> VCC)
  2. R7 (R7->C6, TRIM DIRECTION-X SW,TRIM DIRECTION-Y SW, TRIM THROTTLE SW, (C6 -> GND))
  3. n/c
  4. R3, C3, CD1, D1 (cathode) (C3-> GND, CD1-> GND, D1 (anode) -> GND)
  5. R12 (R12 -> K2)
  6. R13 (R13 -> K1)
  7. n/c
  8. R5 (R5 -> LED1)
  9. R6 (R6 -> C1, C5 and Base Q1 (C1-> GND; C5 -> C7, X1, Base Q2 and L2))
  10. n/c
  11. GND
  12. R10 (R10 -> THROTTLE SW)
  13. R8 (R8 -> DIRECTION-X SW)
  14. R9 (R9 -> DIRECTION-Y SW)

Other connections

  • VCC -> R2, R3, R4, L2, C4 and L1
  • 0V -> POWER SW (POWER SW-> GND)
  • C4 -> GND
  • R11 -> C7, Emitter Q2 (R11->GND)
  • Collector Q2-> R4 and X1
  • L1 -> C2, Collector Q1
  • Emitter Q1 -> GND
  • C2 -> L3 (L3-> ANT)

Components

  • R1 10k
  • R2 27k
  • R3 220R
  • R4 68k
  • R5 1k
  • R6 8.2k
  • R7 100R
  • R8 100R
  • R9 100R
  • R10 10k
  • R11 100R
  • R12 1k
  • R13 1k
  • C1 221
  • C2 221
  • C3 393
  • C4 104
  • C5 33
  • C6 0.47 (0.67/J.6?/
  • C7 8
  • CD1 100uF 16V
  • L1 1.1 uH 10%
  • L2 1.0 uH 10%
  • L3 2.7 uH 10%
  • Q1
  • Q2
  • D1
  • LED1
  • K1
  • K2
  • X1
  • SW1 THROTTLE
  • SW2 DIRECTION
  • SW3 POWER
  • ANT

Circuit Diagram

Pending…

The manual

In French, TX-9009_5153_manual_fr

This site looks promising but seems to be malware, RC Helicopter Manuals

Enhanced version

The videos above mention that it is a 3 channel helicopter, but the comments in the above link mention an enhanced version, like this, the 4-5CH RC Helicopters TX- 9009 RC Helicopter model enhanced version metal gyroscope, which as the name suggests has a gyroscope and 4-5 channels:

Short Description:
1) built-in gyroscopes, flight stability, steering precise and flexible, intelligent control system, full-scale remote control.

2) 360 degree exact directional, smooth remote control performance and power saving features of new research and development, care of the battery mode, to extend the service life, the unique control of the propeller perfect sense.

3) vivid design, comfortable control.

4) humanized design, excellent maneuverability.Sales model: mix order.
Quantity: 1 Piece
Package Size: 48.0 * 20.0 * 15.0 ( cm )
Gross Weight/Package: 1.5 ( kg )
Specifications:
Aircraft: 350mmx70mmx180mm (length x width x height).
Main propeller diameter: 300mm around .
Flight Function: up, down, forward, backward, turn left, turn right and hover .
Battery Type: 3.7V 1000mah Lithium Battery .
flight time:10-15-minute .
flight altitude :20-25 m.
Remote control range: 50 meters .
Charging time :100-110 minutes.
Features:
1) built-in gyroscopes, flight stability, steering precise and flexible, intelligent control system, full-scale remote control.
2) 360 degree exact directional, smooth remote control performance and power saving features of new research and development, care of the battery mode, to extend the service life, the unique control of the propeller perfect sense.
3) vivid design, comfortable control.
4) humanized design, excellent maneuverability.
5) The use of coaxial helicopter propellers, moving back to the design of the structure, smooth operation and convenient flight.
6) metal steel and drop a good performance.
7) Metal steel frame to prevent fall touch damage.

Attempting to determine the IC

The following google searches reveal very little:

This is as far as I have got to date.

Handy tip

Use a 1-8S LiPo Tester with the helicopter

 

 

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