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Old Aug 05, 2007, 11:50 AM
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Help!
newbie crashes aerobird3 - needs advice - how do i test circuit board?

i've never flown rc before, ordered this aerobird3 online, flew it 3 minutes and spiraled it into the ground. After stewing for a week, i just got online here and have spent 3 hrs reading much of what i should have done in advance. o well.

i fixed tail mast, taped wing, ordered new V tail (due in a few days), i see circuit board broke small mount - so i'm epoxy'n that, but my main question is:

I've removed the guts (circuit board, motor, . . ) and plugged the battery up to see if things work, and all i get is an initial movement from the two servos, but then no motor spinning on throttle up and no movement of servos. Again, the servo's jump when I initially plug the batt in, but after powering the radio up, i continue to get only a beep from the motor and no response from servos. is my circ board dead?
Also, one of the servo plugs was undone from the wreck, and i wonder the correct location for it to be plugged in, since there are like 6 pin locations to plug it on? i've been looking for a pic on the web, but no luck ? I see challenger circ board/servo pics, but they look diff than my new aerobird3.
Any help would be appreciated. thanks, Doc
wawazat-u@att.net
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Last edited by DocHolidaay; Aug 05, 2007 at 11:58 AM.
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Old Aug 05, 2007, 03:47 PM
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Raleigh, NC
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Quote:
Originally Posted by DocHolidaay
...
Again, the servo's jump when I initially plug the batt in, but after powering the radio up, i continue to get only a beep from the motor and no response from servos. is my circ board dead?
...
This statement leads me to believe you plug in the battery to the plane and then turn on the transmitter. The proper procedure is to first turn on the transmitter and then plug in the battery to the plane.

Which way are you doing it?
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Old Aug 05, 2007, 04:59 PM
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Sacramento, CA
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why don't you take some detailed pics of the receiver board and where it was damaged and we can better help you based on those.

dave mc
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Old Aug 05, 2007, 07:19 PM
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Quote:
Originally Posted by davemac2
why don't you take some detailed pics of the receiver board and where it was damaged and we can better help you based on those.

dave mc
here are some pics - no real visible damage, to me, except circ board mount. The servos initially move when ever i plug the battery in, then the motor beeps every few seconds. Doesn't matter whether i have tranmitter on first or not, the servos or motor will not work when transmitter controls are moved. i've wiggled wires, moved the servo plug (on the one that fell off in the crash - or from me fishing the board out of cockpit - I need guidance on where it actually belongs) to various pins to see if it makes it all start working. the servo breifly moves no matter which of the 5 pin options i slide it on. so, any thoughts?
thanks guys, Doc
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Old Aug 05, 2007, 10:08 PM
Oldie but goodie
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United States, CA, Orange
Joined Jun 2003
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The area you show as being repaired is right next to the RX crystal.

I'm guessing the RX crystal took a hit in the crash process, they are very delicate.
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Old Aug 06, 2007, 08:34 AM
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Quote:
Originally Posted by Popsracer
The area you show as being repaired is right next to the RX crystal.

I'm guessing the RX crystal took a hit in the crash process, they are very delicate.
Are crystals able to be tested/replaced - or must i do the whole board? I have done minor solder/repairs a few times on circ boards.
thanks for your input. doc
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Old Aug 06, 2007, 03:12 PM
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Doc, you could potentially replace the crystal since it appears to be socketed. However, you need to find a replacement. You may want to first try to pull the crystal and then re-seat it. As well, check very carefully with a magnifying glass or microscope around that part of the PCB for any micro cracks in the solder joints on some of the heavier components such as the xtal leads or the RF transformers. Even if you don't see any cracks, if you are handy with a soldering iron, re-touchup some of the joints on that end and try it again. Another option would be to temporarily remove the antenna wire and put anothe piece of known good wire in and give that a try.

As well, be sure the battery you are testing with is fully charged.

As for where the other servo lead goes, don't worry about that until you know the receiver is working again. Then, just try them all with the colored leads in the same orientation as the servo already plugged in. It looks as if that receiver may be set up for 5 or 6 channels.

As for a potential, unconfirmed crystal source, you can try Hobbico RedHawk crystals of the exact same frequency as printed on your receiver crystal: Hobbico Redhawk Crystal Sets . No one has confirmed that they actually got these to work in a HZ transmitter or receiver. However, they seem to use a similar receiver design. Crystals can be either series or parallel resonant, and can also be spec'ed for different load capacitances, so who knows. Assume replacing the crystal as a last resort. If it works, please do report back.


dave mc
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Old Aug 06, 2007, 07:24 PM
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i'll see if i can reseat the crystal and closly inspect the items, etc - thanks again.
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Old Oct 24, 2007, 09:25 PM
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Doc, have you found a solution yet?
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Old Oct 24, 2007, 09:35 PM
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What's up Doc?
Sorry i just couldn't resist. Where are you located? Is there a RC club somewhere close to find some hands on help? Or maybe a local hobby shop?
A local club might have an instructor to help you get that plane flying.
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Old Oct 27, 2007, 05:34 AM
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i quit

it's in pieces in the garage. i was hoping i could get the hang of it without such nasty damage - oh well . . . .someday i'll get back to it. thanks for inquiring.

Quote:
Originally Posted by planeaddiction
What's up Doc?
Sorry i just couldn't resist. Where are you located? Is there a RC club somewhere close to find some hands on help? Or maybe a local hobby shop?
A local club might have an instructor to help you get that plane flying.
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Old Sep 13, 2009, 09:25 AM
Can we lift the embargo?
kenstogie's Avatar
menands flats, NY
Joined Dec 2006
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Mine is doing the same thing but I don't think it's the RX as I swapped that for a AR6100e DSM2. The motor just beeps. I'll dig into it when I am so inclined and report back.
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Old Jan 21, 2010, 09:47 PM
Can we lift the embargo?
kenstogie's Avatar
menands flats, NY
Joined Dec 2006
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I really like the airframe of the AB3's but I really dislike the electronics of them. So junk them and put a brushed esc in there, a lipo and a decent reciever and a vtail mixer if you need one or use a computer radio.
Incidentally the motor beeping is a bad esc.
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