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Old Apr 12, 2015, 08:02 PM
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IT'S NOSE HEAVY!!!!!!!
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1st RC car...servo issue

So...I've been into planes since 1987, but this is my first car; a Losi 1/24 SCT.
The steering servo has gone goofy, and a quick online search and servo removal shows it has a 5 wire servo.
Is the 3-pin plug (in picture below) on the other end of the board for a 3 wire servo?
I've got so many random micro servos i could throw in until they go bad, that purchasing a new 5 wire servo is silly. (Apparently I'll have to mod the output arm to match square drive of servo saver too, no biggie)
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Old Apr 13, 2015, 08:37 AM
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Did I make the A Main?
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The resolution is too small to see the 3 pin slot you're referencing, chances are that slot is a JST-XH port for 2S power input.

Pretty good discussion here on 3 wire and 5 wire servos:
http://www.rcgroups.com/forums/showthread.php?t=1051518
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Old Apr 13, 2015, 09:24 AM
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Here's a better pic. ..it could be a lipo plug...
Nearly dead center of frame, servo plug at far left.
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Old Apr 13, 2015, 10:12 AM
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Did I make the A Main?
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that doesn't look like a JST-XH port, and yes, that sure does look like a 3 pin output for servo.... I would hook up a voltmeter to the pins and see if it's pushing out any voltage. I think the signal output is something like a variable 0.5 to 0.6V or something like that as you apply steering input where the other two pins should be a constant 5.0V or 6.0V depending on the BEC output. If your readings are in that ballpark, then it should control a 3 wire servo as you predicted.
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Old Apr 13, 2015, 12:53 PM
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If it's the 2.4ghz conversion esc or the newest scte or rally x esc then yes those 3 pins are for a 3 wire servo.

Number 5 in the 1st post of this tutorial shows different ways we mod a servo horn. http://www.microtforum.com/viewtopic.php?f=45&t=21711

Edit: I'm not sure which way the servo plugs into the esc so have a close look at the esc for any writing. Either that or check the manual.
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Old Apr 13, 2015, 06:42 PM
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Here is the esc manual. For a 3 wire servo the negative wire is towards the esc's antenna wire. http://losi.com/Products/Support.aspx?ProdID=LOSB9524
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Old Apr 13, 2015, 06:58 PM
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IT'S NOSE HEAVY!!!!!!!
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Just now got home and quickly plugged in a disposible servo, and it works!
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Old Apr 13, 2015, 07:03 PM
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Great to hear it works . Most 3 wire servos will work way better than Losi's overpriced 5 wire servo.
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Old Apr 13, 2015, 07:41 PM
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Hs55 case is just a hair too big (roughly equal to the thickness of one wall of its case) ...and a wee bit too much travel, as the "drive pin" spins up and out of the groove in the linkage, hmm...
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Old Apr 13, 2015, 08:14 PM
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Can you adjust the servo travel on your transmitter?

You might be able to cut the chassis to make it fit. I would just get another cheap servo the same dimensions as the stock 5 wire servo. The 2nd post in the tutorial I linked to lists a few parts and servos I've seen used in builds. The HXT500 from hobbyking works with a little shimming and is dirt cheap.
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Old Apr 13, 2015, 10:01 PM
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Ah...didn't even think about shimming a smaller one that i have.

Cheapy included transmitter has no end point adjments...well, actually, it has a "sensitivity" knob which can be turned down. The 4 yr old likes to mess with the knob the entire time he's using it, though.
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