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Author Topic: Nano Biscotte V3 Common Issue  (Read 6389 times)

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Offline Death.is.a.Star

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Nano Biscotte V3 Common Issue
« on: April 15, 2017, 09:34:18 PM »
Hey saber world.

Don't post on here often, but I'm reaching out to discuss an issue i have with the nbv3. This is a persistent problem I've had with two saber builds that have NBv3 soundboards.

The main LED seems to pulse and dimly light up when powered off. Im currently having this issue on a graflex 2.0 build with a goth 3d knight chassis that i mean to sell once i figure this issue out... Any ideas anyone? I'm stumped. I've never had this issue with a Spark 2, Crystal Focus, or Prizm soundboard, just the nano biscotte.


MTFBWY

Offline erv

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Re: Nano Biscotte V3 Common Issue
« Reply #1 on: April 16, 2017, 01:35:45 AM »
If the led is lit, current is passing thru. As the NB uses the exact same driver part as the prizm (and it's also the pre-drive part on the CF main channel).

There's a chance your led is returning to ground in a way or another, sometimes due to bad isolation of the LED itself (no cool tape) via the chassis or the hilt.
It would be nice to know as well if this is happening straight after power off (blade retraction) or once you reach deep sleep.

please post wiring pictures of your board and led too

Offline IceSaber

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Re: Nano Biscotte V3 Common Issue
« Reply #2 on: April 16, 2017, 01:56:08 AM »
I don't know what cool tape is but I had an issue with a build where the blade would light up regardless of whether ice flipped the activation switch or not. It turned out the led retention screw was grounding the led assembly to the inner core. I couldn't see how this was happening but touching the soldering iron on each led pad on the tri cree melted some solder and hardened in a smoother position I guess. It fixed it. It's not like I had lots of solder on either but it worked. My first build worked flawlessly in that respect. Incidentally that one was a spark 2 lol. But I'm confident it's nothing to do with the board in my example. It might be the same with yours.

Offline erv

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Re: Nano Biscotte V3 Common Issue
« Reply #3 on: April 16, 2017, 03:54:21 AM »
the other possibility is that you damaged the driver due to excessive current (no resistor or incorrect one). Thought the part could withstand 6A, a pure short on the battery or no resistor could damage the part. The result is that the driver cannot be further closed totally due to the damage and some current keeps flowing thru it.

Offline Death.is.a.Star

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Re: Nano Biscotte V3 Common Issue
« Reply #4 on: May 21, 2017, 02:46:08 PM »
Still can't figure this out. Ive taken the whole saber apart twice now and rewired the whole thing. In my B/B/W led set up, only the blue leds are faintly flickering on and off. This happens before deep sleep even. All my leds are wired to a common positive return to the board as per the manual, but only the blue flicker.

Saber works perfectly otherwise.

Help me fx-sabers forum community, you're my only hope!
« Last Edit: May 21, 2017, 02:50:20 PM by Death.is.a.Star »

Offline erv

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Re: Nano Biscotte V3 Common Issue
« Reply #5 on: May 21, 2017, 09:31:05 PM »
as posted above we are still expecting some wiring pictures, the led you've used and the resistor values

Offline IceSaber

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Re: Nano Biscotte V3 Common Issue
« Reply #6 on: May 22, 2017, 05:01:32 AM »
Does it happen when the led assembly isn't inside the hilt's core?

Offline Death.is.a.Star

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Re: Nano Biscotte V3 Common Issue
« Reply #7 on: May 23, 2017, 05:41:34 AM »
Hey guys,

Thanks for your responses. I've attached those pictures below, as you can see it occurs even out of the chassis/LED module. Really perplexed by this as I've since taken saber apart and checked everything again. I've used 1ohm 1 watt resistors on the blue as per Khal at KR sabers.




Offline erv

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Re: Nano Biscotte V3 Common Issue
« Reply #8 on: May 23, 2017, 06:32:37 AM »
there's no such thing as "1 ohm resistor like the other guy did" as you need to measure your leds to find what resistor you need.

try without the accent led and disconnect the FoC die.

Offline CHEWBACCA

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Re: Nano Biscotte V3 Common Issue
« Reply #9 on: May 23, 2017, 07:07:29 AM »
from going by that pic I think you may have an issue with the main LED shorting somewhere.

The reason I say that is because the accent LED that is on top of the board is connected to the main LED but it is not lit.  If it were a transistor then you would think that LED should be lit as well.

Can you move that LED out of the way and take a good clear pic of the transistor under it?

Offline IceSaber

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Re: Nano Biscotte V3 Common Issue
« Reply #10 on: May 23, 2017, 09:37:11 AM »
It could be the photo but on the "non SD card side" of the board the positive and negative look like the solder could be touching.

Offline jbkuma

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Re: Nano Biscotte V3 Common Issue
« Reply #11 on: May 23, 2017, 10:16:20 AM »
Where's that 3.3v pad going? To an accent I hope..

Offline erv

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Re: Nano Biscotte V3 Common Issue
« Reply #12 on: May 23, 2017, 10:23:45 AM »
interested by a complete wiring diagram with the accent and all cause it might be the reason

Offline Death.is.a.Star

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Re: Nano Biscotte V3 Common Issue
« Reply #13 on: May 23, 2017, 10:37:56 AM »
There are two accent leds. The crystal is being powered by the 3.3v pad and works fine. The second is the led wires in parallel with the main led. I will remove it tonight when I get home and see if it's the problem and take some pictures, although I have done so already and there was still flickering in the main leds when powered off so I don't think it's the issue. I'd also like to add that normally the accent led wired in parallel to main led flickers with the main when off, demonstrating the same problem. However, they aren't always misbehaving, only about half the time.

According to my own calaculations (ohms law) the resistors listed above should be sufficient for the blue LEDs. All I meant to say is that they were sourced from an order from kr sabers. I have used the resistors in other similar builds with success.

Thanks again guys I appreciate all the help and the responses from Master Jedi Erv plecter himself
« Last Edit: May 23, 2017, 10:40:23 AM by Death.is.a.Star »

Offline IceSaber

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Re: Nano Biscotte V3 Common Issue
« Reply #14 on: May 24, 2017, 02:49:59 AM »
I agree with seeing a wiring diagram. It's difficult to see the problem with those pictures.

I don't mean to divert the topic but I've been looking into resistors a lot lately (and the math is fun).
In terms of resistance, I'm sure Erv will tell you that the 1ohm 1w is overkill for that you need. Personally I don't think it's a problem, and actually helps the battery last longer with the NB, and in turn reduced the chance of phantom swings occuring before recharging. The normal resistor required would be..
Resistance = Voltage difference/Current
3.7 (battery voltage) - 3.38 (blue forward voltage) = 0.32 voltage difference
0.32/1 (1000mA forward current of LED) = 0.32ohms

Watts = Voltage difference * Current
0.32*1 = 0.32watts

Erv knows much better than me but I'd assume that if you use a 1ohm resistor where only a 0.32ohm is required, you'd be reducing your LED brightness by around 60%. In practise though, I've used a 1ohm resistor and noticed very little brightness difference. The main plus for me was the longer battery uptime.

 

retrousse