HobbyKing Forums
Forum Home Forum Home > Product Specific > Transmitters and Receivers
  New Posts New Posts RSS Feed: Turnigy 9X "Lightning the Display"
  FAQ FAQ  Forum Search   Calendar   Register Register  Login Login

Turnigy 9X "Lightning the Display"

 Post Reply Post Reply Page  <1 345
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
jhsa View Drop Down
N/A  (N/A)
USERID: 0
Newbie
Newbie


Joined: 02/May/2010
Online Status: Offline
Posts: 1
  Quote jhsa Quote  Post ReplyReply Direct Link To This Post Posted: 01/Jan/2011 at 12:50am
Originally posted by yulo99

Hi!

I have just did backlight mod as described by "ex-trainer". But there is sth. strange: switching light on causes radio reset! is it normal?  (I took +5VCC and GND from the mainboard)

and the second issue: is it ok that inverter generates some sound when activated?




sometimes the 5V regulator can't handle the backlight circuit and the tx reboots. and that is not normal. some people had the same problem. try to put a resistor in series with the backlight 5V line. try  25 to 40 ohm resistor. hope this helps..
Back to Top
s_mack View Drop Down
Platinum  (CA)
USERID: 544652
Bargain Addict!
Bargain Addict!


Joined: 24/Jul/2010
Online Status: Offline
Posts: 27
  Quote s_mack Quote  Post ReplyReply Direct Link To This Post Posted: 01/Jan/2011 at 2:28am
That depends on where you got your backlight from!

If it is the 9x el backlight kit from smartieparts (dot) com then yes, the reboot issue has been solved with a 25 ohm resistor.  However, yulo99 stated that it reboots when he turns the light ON, and the issue discussed with the smartieparts kit was always when the light was turned OFF.  So I wonder if this person has a different kit and different issue.  To be clear, the 25 ohm resistor fix is VERY SPECIFIC to the smartieparts board.

The vast majority (all?) of the other kits out there use inverters while the smartieparts kit uses a superior EL driver IC circuit.

yulo99 also asked, "is it ok that inverter generates some sound when activated?"... and the answer is "yes".  EL backlights run on AC current, not DC (battery).  Any time you convert from DC to AC it is impossible to do so with 100% efficiency.  The "wasted" energy comes out as sound and/or heat.  If you are using an inverter, then the sound is very noticeable (annoyingly so).  If you're using the smartieparts kit, there is still sound, but it is much more quiet because it is much more efficient.

 - Steven
Back to Top
sklenar View Drop Down
Platinum  (SK)
USERID: 69420
Newbie
Newbie


Joined: 04/Mar/2009
Online Status: Offline
Posts: 14
  Quote sklenar Quote  Post ReplyReply Direct Link To This Post Posted: 10/Jan/2011 at 9:09am
well, if someone will just hook wires with On/Off switch to 5V rail inside Tx, and there is any capacitor in backlight unit, the voltage at the Tx board is simply shorted to discharged capacitor, at the very first moment. While capacitor is discharged, it is simply a short circuit - reboot is natural..
Resistor should help, if backlight circuit can work with it. Anyway, internal 5V regulator is not designed with additional load in mind, and result is not predictable without looking at it (both cooling and max current).
Back to Top
Wambly View Drop Down
Platinum  (AT)
USERID: 920092
Newbie
Newbie


Joined: 03/Mar/2012
Online Status: Offline
Posts: 4
  Quote Wambly Quote  Post ReplyReply Direct Link To This Post Posted: 04/Apr/2012 at 7:25pm
Has somebody make the Mod with a NPN Transistor, or everybody with an FET?

How many current is needet for the backlight?

Thanks Wambly
Back to Top
s_mack View Drop Down
Platinum  (CA)
USERID: 544652
Bargain Addict!
Bargain Addict!


Joined: 24/Jul/2010
Online Status: Offline
Posts: 27
  Quote s_mack Quote  Post ReplyReply Direct Link To This Post Posted: 04/Apr/2012 at 8:08pm
You've dug up a very old thread... but what "mod" are you talking about exactly? This particular thread has been about using an EL panel. That doesn't require a FET at all.

In general, for backlight there are two main options:

1) EL panel. This requires either an inverter (not recommended - too much audible and FM noise) like the original author used, or an inductor based EL driver IC, which is much more complicated but vastly superior. The only IC based one I know of is the SmartieParts board (which I sell - full disclosure). With custom firmware (the SmartieParts board is also a programmer for custom firmware), the backlight can be assigned to any switch and therefore controlled by the radio's CPU.

2) LED backlight that HobbyKing sells here. Its cheap, bright, and effective... but it can't be controlled by the CPU/custom firmware. At least not without modification.

So I figure by your question, you're asking about that particular modification... which I don't believe has anything to do with this thread. But if that is what you're asking about... sure, you can do it with an NPN. Why not? But which one? You have to carefully select it, while almost any (mos)FET will do just by the nature of what they are.

To answer your "how much current" question... we have to know what backlight you're referring to. And if its the LED, then how much current depends on how much voltage you're giving it and it varies as the battery goes from full charge to not. That's not really the proper way to drive an LED (they're supposed to be constant current devices) but it works.
Back to Top
GhostMaster View Drop Down
Platinum  (PT)
USERID: 1327552
Newbie
Newbie


Joined: 11/Feb/2012
Online Status: Offline
Posts: 5
  Quote GhostMaster Quote  Post ReplyReply Direct Link To This Post Posted: 12/Apr/2012 at 6:03pm
Great mod, i like this radio, buyed one a couple days ago on HK :)
Back to Top
 Post Reply Post Reply Page  <1 345

Forum Jump Forum Permissions View Drop Down

Bulletin Board Software by Web Wiz Forums® version 9.54
Copyright ©2001-2008 Web Wiz

This page was generated in 0.098 seconds.