Dead 9x after flash attempt

[m00se]

Well it seems to be all ok, i will keep bench testing it,

in the meantime, could I us one of these:
http://pdf.datasheetcatalog.com/datashe ... 7641_1.pdf

for the backlight control as shown here:
http://www.rcgroups.com/forums/showthread.php?t=1541190

thanks

[MikeB]

I can't get the .pdf to load from your link, so I can't answer.

Mike.

[jhsa]

Here it is.

[MikeB]

That is a bipolar transistor (not a MOSFET) so will need a resistor in series from the processor signal to the base.
It is also rated at a collector current of 0.15A (150mA), so make sure the backlight doesn't take more than that.

Mike.

[m00se]

Thanks guys, I will hunt a resistor somewhere in the scrap bin, (I have yet to find a local component shop and dont want to pay ebay shipping for every single thing needed)

I guess that the backlight might draw more than that, but I will investigate. I will also hunt a small mosfet somewhere and see if I can get a more suitable component.

So far it looks like the 9x is up and running ok, I havent had any more MCU resets. I wonder if infact they were also being caused by mechanical stress on a dry joint when activating the rather stiff 6 position switch ?

[jhsa]

On my first 9x I used a mosfet from an old servo..

João

[m00se]

I just read that on another thread somewhere , posted by you,

I have also read that the current draw on the backlight is something like 15ma, so I will go ahead and try it out with the c945

[m00se]

Here is a pic of what I have done,

I have gotten rid of the big bulky connector, took the smd resistor off and soldered it directly to a pad on the pin that the tutorials showed it being connected to.

I then soldered the C945 directly to a grounding pad, keeping it nice and secure, and with a 1k resistor inside the heatshrink connected the other pin to the pad on the atmel. routing it round the back of the other inputs to try and avoid any interference.

I have the following pins on the C945 connected to the following places,
Emitter - GND
Collector - LCD -ve
Base - 1k , atmel

Hopefully thats all ok

[m00se]

Seems to work perfectly,
great

[jhsa]

Are you powering the backlight from 5V? Did you place a resistor in series with the backlight or is there one already? Is that the SMD resistor you refer to?
If powering from 5V, the series resistor value should be around 200 ohms, to keep the backlight current low not to overload the transistor, or even worse, the 5V regulator as that could cause it to overheat and shut down. That is something you don't want to happen, specially when flying. That regulator is kinda working on it's limit already. It's only 100mA

João

[m00se]

the guy who did this tutorial is powering it like this

https://plus.google.com/photos/10535523 ... 9930559124

all that I did was find a pad connected to the same pin that he connects the resistor to and then soldered it up ,
I didnt even check the voltage, I will take a look and see whats what

I dont think I will ever put the screws back in this thing, next I will attempt the telemetry mod

[m00se]

The pin you can see it powered from in my photo above is battery voltage,

[jhsa]

Ahh didn't pay attention to that detail before, sorry.. Then it needs an even greater resistor value or the LEDs won't last long
But if it is working....

João

[m00se]

what should i change it to then ?
the screen looks slightly brighter on the led side than the other side , and i really dont wanna burn them out and have to order a new one,

[jhsa]

That would depend on the battery you are using to power the radio I guess.. but if that resistor is a 470 ohm one, I think it should be ok even if you use a 12V battery..

João

[m00se]

its the same resistor as it came with, so id assume it is ok, its powered by the same source