DragonOSD+V2 with RTH - Page 155 - RC Groups
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Jul 17, 2010, 12:43 AM
what goes up, must come down..
AussieHoppy's Avatar
Originally Posted by Cralis
Crashed!! And this time... I have NO idea what caused it. I did one short flight, and the plane went into a spiral, so I landed... and reversed the ailerons.

Launched, and it just banked right and went in...

And then.. I could smell that horrible burning smell!!!

ESC was beeping as if it had lost contact.

Opened the canopy... actually, the canopy came off... and I unplugged it all. I powered down my ground station. Then, I powered up the plane again.. and the ESC armed OK, and the servos twitched. But.. I had no control of aileron or elevator (the two things going into the OSD). So I powered down... and then noticed that a power pin had melted off, and the power to the OSD was detatched!!!

So, I packed up, and came home...

I see that again... the ground cables are all melted on my video harness!!

Argh!! Starting not to enjoy this now...

Analysing video, as I recorded it all...

Post crash: I've just reviewed the crash, and it's a mistake I made.
I changed the settings... and then removed my goggles to do a LOS launch... BUT.. I forgot to exit the menu!

So I had no control of the plane.. except for Throttle.......................................... ....
Oooohhhhhh.... that hurts, mate... I feels yer pain...

repairable without too much damage?
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Jul 17, 2010, 01:11 AM
I love FPV!
Cralis's Avatar
All OK... I've somehow melted a pin off my DragonOSD+ somehow... and I need to rebuild my video harness... This is the second time I have melted a ground wire. Not sure if the DOSD+ is OK.. Will only know later...

The pin is an issue though... I have no idea how to fix that.
Jul 17, 2010, 01:34 AM
I love FPV!
Cralis's Avatar
EasyStar Crash due to my error (7 min 6 sec)

Jul 17, 2010, 02:16 AM
de wk7r, qsl?
That hurt to watch, Cralis...

Maybe I should have mentioned this earlier (before the power pin on the dosd+ exploded in a ball of plasma..) but call me silly, doesn't it seem like your plane in autopilot always turns to the right? Even when you were in the menu there it immediately turned to the right when you launched it...

have you done the set ail/ele neutrals option on the main menu? verified that when you are within hit distance (ie, the autpilot should not attempt to turn in any particular direction...) and you go into autopilot, do your ailerons immediately torq to the right?

Just an observation, I may be way off base, but my guess is that the dosd's idea of "center" is a little right of center...(your plane must be conservative!)

de wk7r
Jul 17, 2010, 02:28 AM
I love FPV!
Cralis's Avatar
Thanks Sean.

When I let go of the sticks, at the moment, the plane seems to go quite straight. If there is an inclination to bank, it's pretty small amount, but on my next flight, I'll try trim it dead straight.

I think I launch it slightly squint though. All my take offs are to the right. I think it's subconsiously to make sure the left wing doesn't hit my head. So I throw it at a slight bank, and from there, it just got worse.

"have you done the set ail/ele neutrals option on the main menu?"

No. What's that? I only know of a 'REV and NOR' setting.

I've been sitting here silently look at my OSD, with it's extremely shortened ground pin... and my power splitter (Battery splits to ESC, Video Harness and OSD)... wondering what the hell to do next. This is the 2nd time I have lost my ground wires. Last time, the power connector popped off, so no physical damage to the OSD. This time, the pin is a gonner. I don't have the tools, nor the skills to fix it, and don't know anyone around who does. This is my 3rd variation now. I had the ET which was wires-galore. Then I got the SimpleOSD which was simple, but didn't work too well. Now this, but now I'm thinking it's maybe a bit too technical for me as far as wires is concerned. I'm actually now thinking, 'Do really need an OSD?!'. I was soooo looking forward to trying tome RTH stuff... and then this happens. I guess it's like a cook, wanting to pilot a space ship. I'm just not qualified...
Jul 17, 2010, 03:01 AM
Registered User

Don't give up easily. This is the learning curve and this is where one decides if you will beat the problem or be beat by it. Sometimes, the learning is the fun part. Take a logical approach to these things - step by step. Rigorous testing usually helps.

Here are some things you can do:-

1. Learn to solder well, make sure you have the right tools and technique. Changing pins are really easy to do if you know how.

2. Go over your wiring and think about robustness and reliability. Are the exposed bits that might short out easily. Are the OSD pins near other metal bits or exposed wires.

3. Do things the proper way, even if it takes longer and cost more. Don't be in a hurry to get to the result.

If you're feeling scared - don't. What's the worst that can happen - blow an OSD? melt a wire? No big deal. You can recover from these things but the stuff you pick up on the way will be yours forever (until senility sets in that is) and will stand you in good stead in many other fields and ventures.

A cook CAN fly a space ship if he's determined enough and willing to pay the price. Feeling unqualified? - qualify yourself. Today, with the Internet and the search engines, we have unprecedented access to information and doing stuff is so much easier than it was back when I got into electronics (I was a student in grade school then). When I started soldering, there was no internet. In fact, I didn't even have a soldering iron. I held a screwdriver over the fire on the stove until it was red hot, and then tried to solder with it before it cooled down too much. You can't imagine the trials I had to go through, the burns I got, stuff I damaged. If I had given up then, I would not be doing what I am doing today.

As Churchill once said (supposedly) - "Never, never, never give up."

Jul 17, 2010, 03:23 AM
I love FPV!
Cralis's Avatar
Thanks Daniel.
My analogy was maybe a bit wrong... The cook wants to fly to space, because he loves flight, and as keen on seeing what space is like, but it's possible his interest isn't in building the space ship.

Ok.. I'll take my time to rebuild it. Removing the pins - I only have a soldering iron. I could hold the tip against all three pins at the back, and fill from the front, and they might come out. But ... I'm worried the holes would refill with solder, and then I can't get my new pins back in. I need more than a soldering iron, right?

Some good news. There's around 1mm of melted pin still available to me. I was able to connect a connector to it. The +ve is all the way up into the plug.. and the remaining 1mm is enough for the plug to grip, and have contact. I was able to connect it and it still works, again. Man, these things are robust.. but .. you need a non-melting metal for the pins.

I was able to download my flight (GPS). PC Commander reports I got to 254 meters away.. 78 meters up.. and travelled for a total of 1.27km! Cool software!

And I tracked the flight in Google Earth... The short one didn't feature much... heh..

Might just open some beer and try forget about today, and reevaluate tomorrow when I'm in a better mood..
Jul 17, 2010, 03:48 AM
--Parking Lot Pilot--
That's the attitude Cralis..
I like the Software track capability in Google Earth... sweet! I am a newbie to this and I have acquired a DragonOSD but I think it is a much older one than this version that you are using. It's like 1.1b and when DW was associated with IF. I hope it is still usable. If anybody can point me in the right direction for help it would be greatly appreciated. I have no literature on it at all. Thanks.
Jul 17, 2010, 03:50 AM
Registered User
Hi Cralis,

The correct way to remove the pins requires some investment in the correct tools. A few things to note:-

1. It's hard to remove all three pins at once. You already know this. Since you do not need to preserve the pins, you can remove them one at a time - which is easier. To do this, you need to pull the black bit of plastic off the board - which can be done by cutting or heating up the pins then just pulling it out.

2. The solder on those pins are high temperature solder - melts at 310C+. So make sure your iron has the right wattage for the job. The iron's bit needs to be shiny and coated with solder. If it's dull, dirty - it's probably the wrong tool to use.

3. You can remove solder in the holes using several methods. A solder wick may work. A solder sucker or remover works better. If your iron is hot enough, just melt the solder and, using a straw, give it a good burst of air and it should clear the hole. There are many methods that will work, but just as many that won't.

Bottom line - use the right tools. You may need to buy them but usually they don't cost that much. The iron needs to be hot enough, and the bit needs to be correctly maintained and in good shape. You can load up the pin with low temperature solder to make it easier to melt.

Jul 17, 2010, 05:30 AM
I love FPV!
Cralis's Avatar
Would this be suitable?
Jul 17, 2010, 06:11 AM
Registered User
Yes. Slightly smaller may be better but this should do the job. Just remember what I said about solder melting temperatures. The factory that assembled the boards used RoHS compliant solder, so the melting temperature is higher than normal - meaning that they will solidify really fast. You need a lot of heat in there to make this work.

The solder sucker will not work perfectly. The trick is to remove the black plastic and remove them one at a time. If you can do that, you should have no problem.

Jul 17, 2010, 07:02 AM
I love FPV!
Cralis's Avatar
Ah.. now.. could I have found my issue with the ground cable exploding... Check this.

I have rebuilt my harness, the same way as it was before. I then use a multimeter set to something that shows an 'I' when there is no connection, and then it shows a number when there is a connection. So, if I touch the probes together, it shoots to a high number, then comes down to 0. I have been using that to check wires.

(I have the multimeter set to the thing that is surrounded in red)

So, on my harness... I hold one probe to my positive power wire which would connect to my battery postive... and then the other probe, I touch to the negative power wire that would connect to the neg battery pole. And the voltmeter shows I. So, no conenction. So, that's good. There's no short.

I then keep a probe on the positive input wire, an then touch the positive that connects to the camera... and the number shoots up. So.. there is a connection.. again.. good. I do that to all the positive connections, and get good results. I do the same with the ground. One probe to the battery ground connection, and then I touch all the other ground plugs. All good. Even the ground to the OSD.

The Harness checks out OK. No shorts, and everything connects as expected.

Now... the problem!

I connect my mic. Now things go pear shaped!

Do the same test... Hold one probe to the battery input positive wire... and the touch the GROUND on the OSD plug... and.. connection!! So.. something is wrong! When the mic is connected, it seems there is a connection between Ground and Positive.

Could this be why something is shorting out sometimes? Remember, I flew a flight like this, and all was OK... It was during the crash when it shorted somewhere. Is my harness flawed?
Jul 17, 2010, 07:06 AM
When in doubt, throttle out...
badlands's Avatar
Originally Posted by GALLAWAY
That's the attitude Cralis..
I like the Software track capability in Google Earth... sweet! I am a newbie to this and I have acquired a DragonOSD but I think it is a much older one than this version that you are using. It's like 1.1b and when DW was associated with IF. I hope it is still usable. If anybody can point me in the right direction for help it would be greatly appreciated. I have no literature on it at all. Thanks.
The old DOSD thread is here.

Jul 17, 2010, 07:14 AM
When in doubt, throttle out...
badlands's Avatar
Craig, can you do the same test on mic board with is disconnected? (one probe on +, one probe on GND)
Jul 17, 2010, 07:18 AM
Registered User

A couple of things. The meter - let's call it a DMM (Digital Multi-Meter) rather than a Voltmeter because it can actually measures more than just voltages. The mode where you get the "I" and so on, that would be the continuity-testing mode or the ohm-meter mode (which measures the resistance). "I" in this case probably refers to "Infinite" resistance which represents an open-circuit (no connection), as opposed to a short-circuit (connected). Some DMM's have a dedicated continuity testing mode but the one you show doesn't. In this case, you would want to use the lowest range - that is the 200ohm (the omega is the sign for ohms, which is the unit for resistance) range, which is the lowest this meter offers.

Your harness drawing looks okay. I think what happened is most likely that the crash moved things enough to allow a short to occur. This could be a short between the exposed parts of any of the boards, or between adjacent wires with too much bare wire exposed, and so on. You will ideally want all exposed bits of wire covered up with heat-shrink or stripped minimally. A photo of the harness will help. I assume that all your boards and modules are secure, and are not free to move around. If they're not secure, bad things can happen. Basically, any exposed metal is suspect. This would include the bottom side of boards, the metal on the microphone element, and generally any other metal bits.

Last edited by Daniel Wee; Jul 17, 2010 at 07:27 AM.

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