Thread: Discussion Hitec Aurora 9 Transmitter
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Old Jan 01, 2011, 03:59 PM
A.T. is offline
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Hitec Receivers, Minima & Optima Transceive - Polarity of Servo Ports & Servo Leads

Originally Posted by Reegor View Post
I've spent an hour searching this forum, and cannot find some basic information about the Optima modules.
They really need their own, serious, manual. Examples of missing information in manual:
Which pin is negative on the servos? Especially since some connectors are horizontal while others are vertical. (So saying "top pin" is not enough.)
The diagram that everyone refers to,
shows white and black lines with arrows. What is the difference between white and black lines? Why do all arrows point INTO the Optima unit; why have an arrow at all? The ESC and separate BEC are shown connected in parallel to Channel 3, which is not necessary and is probably not a good idea. What is the purpose of the ports that say "Batt?" and are they any different than the others?
Whinging aside, I have hooked up the SPC port on my Optima 9 after my recent brownout, but now servos are not getting power.
The ESC and its BEC are connected through channel 3, and the throttle works fine. The connector coming out of the ESC/BEC has 5v power as it should. The SPC port is connected directly to my 3S battery, and telemetry shows the direct battery voltage eg 12.1v.
But I see only about .3v across the other servo pins, and the servos don't respond at all when I waggle my sticks.
So apparently when the SPC is in use, the BEC voltage is no longer supplied to the servos??
In that case, where do they get power? Perhaps I need a separate BEC connection to the port labelled "Ch 9/Batt" ?
Despite all Alan's work, this seemingly basic information is not available anywhere that I can find.
Has anyone figured this out?
1 & 2.Servo polarity - all known servo brands have used black as negative and red as positive for many years,
the oddity being JR (and clones thereof) which use brown for negative.
The signal lead is usually Yellow, White, Blue or Orange - refer:
Servo - Wiring Diagrams = use with other brand RX. may assist.

3. Batt is simply a suggested port to separate leads for beginner's ready reference, explained:
Optima Transceiver (RX) - Multiple Batteries may be installed - Dual batteries for redundancy or even one for each servo.
Data Port Cannot Be Used as a battery port

4. SPC Port: View 6ch, 7ch & 9ch Optima Transceiver as being two separate entities; a Receiver & Transmitter with separate Servo Controller.
The two plugs with differences highlighted were attached
SPC connection & Lead Detailed 27Dec10. Extract: "2. The jumper must be in the SPC slot when a BEC or battery is used for both RX and servos plugged into any of the servo channels separately or "Y".
. a) SPC provides no power to the servos.
. b) If SPC power supply fails, the receiver stops and as no signal is sent to servos, the servos also stop despite any other power source (BEC/Batteries) plugged into a servo channel. "

5. Which pin is negative on the servos answered 1. above.
Please refer to the shape of plugs and matching shaped slots on the RX case as attached.
No known major brand has the polarity printed/molded on hard case transceivers/receivers as they all rely on the shape of the servo plug/slot

Hitec fully cased transceivers & receivers use polarised plugs and slots which accept both the typical S-01 plugs and also the keyed Futaba "J" plugs
- the key way is also a good indicator as it is always next to the signal lead.
It is possible to force a S-01 plug upside down into a hard case receiver, but no matter as only the signal and negative leads are reversed so there is no damage and the servo simply will not work.
Only soft case receivers have the polarity printed on them, typical example attached.
(as above, servo will not work and no harm if plug upside down and all three pins are lined up)

Aurora A9, Spectra Modules & Optima Transceivers
- FAQ & Undocumented Features

- Mixes, Setups, Tips. {Individual Links often updated}

Alan T.
Alan's Hobby, Model & RC FAQ Web Links

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Last edited by A.T.; Dec 13, 2012 at 06:10 PM. Reason: add .pdf re Pin Polarity
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