New airsoft gun: how might I try to fix it

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
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Fri May 18, 2007 11:58 pm

I just bought an AEG from a friend for only $25! It is an ICS MP5 A4. The reason it was so cheap was because it was broken and I thought I could fix it. It might be the battery is just bad and i need to get a new one, or the motor has just failed. Not shure which one is the cause at the moment. Let me hear what you think.

Anyone ever had a motor go bad on your AEG?
Last edited by origin unknown on Sun May 20, 2007 1:35 am, edited 1 time in total.
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A-98
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Sat May 19, 2007 12:47 am

if its a bad motor...buy a new, working gun. motors are expensive, and hard to replace. if its a battery....i would buy a new battery, cause they are a tad expensive, but it will save you money in the long run. check the wiring also.
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jackssmirkingrevenge
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Sat May 19, 2007 12:52 am

try hooking it up to a chargin adapter, see if it runs.
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TwitchTheAussie
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Sat May 19, 2007 2:20 am

Could I get a pic? Sounds like I'd check the battery first and if the motors screwed just use the barrel
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Sat May 19, 2007 6:58 am

If non of the above works, bypass the trigger switch. They go bad from time to time, all eletric switchs do adventuly.
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hi
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Sat May 19, 2007 5:33 pm

no, i can almost garentee you that the motor is fine, and if its not then dont wast money on an "ultra high power motor", becaus the exact same motor can be purchesed at a RC airplane store for under $15.

my guess is that the speed controler is burn out, the thing that conroles the electricity from the battery to the motor. just srait electricity from the battery can NOT run the motor, the controler steps up the amps and gives it more power, so thats is probably burn out and can replaced for almost nothing.

hope i helped.

also, check al the switches, bateries, and anything else with a volt meter
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Sat May 19, 2007 5:40 pm

@hi
To step up the amps, wouldn't it have to drop the voltage??? And there is no way the speed controller can give it more power than the battery can deliver. It either drops amps for more volts, or drops volts for more amps.
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Sat May 19, 2007 5:47 pm

ESC's (electronic speed control) are different then step transformers. What the ESC does is act as a throttle, gives the motor a smooth transition from stop to full power in stead of all at once.
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Sat May 19, 2007 5:48 pm

Insomniac wrote:@hi
To step up the amps, wouldn't it have to drop the voltage??? And there is no way the speed controller can give it more power than the battery can deliver. It either drops amps for more volts, or drops volts for more amps.
you obviously dont fly rc airplanes or work with electronics, because you can do both.do you really think that you can start a car with 12 volts? you cant even shock yourself with 12 volts. you can step up voltage and amps, you have to if you want to power anything at all, even electric fans step up the voltage a little.

I dont really want to explain it because it would take me all day, but basicly if a battery is rated at 1000 milli amp hours, then it can supply 1 amp for 1 hour. RC cars dont work for three hours because they draw more than 3 amps....

i suggest you stick with spudding and dont become and electrition.... no offence.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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hi
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Sat May 19, 2007 5:52 pm

jrrdw wrote:ESC's (electronic speed control) are different then step transformers. What the ESC does is act as a throttle, gives the motor a smooth transition from stop to full power in stead of all at once.
nope, it also steps up the amps.

if it is a 25amp ESC, the it draws a maximum of 25 amps from the battery, even if its a 1000 mAh batery. if it did work off of the 1000 mAh that it was rated at, then it wuld last for exactly 1 hour, but since the esc steps up the amps, it only runs for a few minutes if you just run the motor.

think of what its rated at as kinda like and engine idoling, but when you run it through an ESC, then its like steping on the gas in a car.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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Sat May 19, 2007 6:19 pm

Lol hi I do have an rc plane... although it is only a 3ch rtf parkflyer, so I didn't have to do any of the electronics.
I'm starting to understand what you are saying but I'm still a little confused. If the motor can't draw the amps it needs from the battery, why can the esc do it? I understand how an esc could step up the voltage, but how can it draw more amps than the motor can. Eg Power a LED with an AA battery and it will run for hours, but put a little 1.5V motor on it and it will only run for a few minutes. There is no esc involved in either of those examples, but the motor will still run, and still draw a lot of power fromt he battery really quickly. (compared to the LED)

Basically what I'm trying to say is how come the esc can draw X amps from a battery, why can't a motor draw those amps?

I understand how stupid my first post was now, of course you can supply more power for a shorter period of time. I wasn't thinking. When I said that I was imagining a constant, set amount of power, say 12V at 1 amp, I was just thinking that the esc couldn't put out any more than what was going in. I didn't take into account that you could draw more than 1 amp from the power supply.
I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

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hi
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Sat May 19, 2007 6:36 pm

simple, because the motor doesnt have a built in esc. you can draw up to 16 times what the batery is rated at, some batterys can even supply more. So if a battery is rated at 1 amp for 1 hour, then you can suck 16 amps out of it, but i wont last very long. thats why batterys get really hot sometimes.

think of ann esc as a vacume cleaner the sucks up electricty and dumps it out the other side much faster.

the motor doesnt work that way, it just takes in what ever is provided to it.

if you take the gun apart then look where the wires go, you will see a little circuit bord, that is the esc.

on an airplane, the esc is adjustable, so thatyou can make the power go up and down. on and airsoft gun it is fixed to maybe 15 to 25 amps (it depends on the gun, and also what the motor needs to pull back the spring).
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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Sat May 19, 2007 7:03 pm

This is the bit that confuses me. Say I have 2 1300mah AA batterys in series, connected to a small 3V motor. It will run for much less than an hour, meaning it is drawing more than 1300ma.(I think) If a motor like that can draw the amount of amps it needs, why do you need an esc to 'pump' extra electricity to the motor??? And how come the battery won't supply that extra power to a motor, when it will to an esc? the battery doesn't go 'Hmm, I'm connected to an esc, better work harder'
I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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hi
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Sat May 19, 2007 7:20 pm

you batteries are A. not charged completly or B. wired in a way that they burn up extra energy as heat. does anything get hot when you run it?

charge them so that you know that they are 100% charged, then run just one battery rather tha two and see how that goes. are you sure that the battery is conneted to nothing but the motor? if it is then the motor should turn very slowly, maybe say around 200 RPM.

i cant really eplain this any simpler than an esc takes energy away from a battery really fast.

it like if you have a bucket of water and it is holding 20 gallons. if you drill a 1/32'' hole in it, then it will leak very slowly, but if you put a pump into the bucket then it drains much faster. does that make sence? now replace the pump with the esc and the bucket with the battery and your set.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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Insomniac
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Sat May 19, 2007 7:26 pm

Yeah I understand what you are saying, but the batteries I use just to muck around with were in perfect condition, they were fully charged and trust me, the motor was doing WAY more than 200 rpm (I had it connected to a small propeller, and the motor was on a balsa wood stick with a fin on the back, and the whole thing was on a string connected to the ceiling) It was kinda like one of those 'flying bird' toys on steroids (the prop kept striking the wall as it got so fast that centrifugal force got it circleing really close to the ceiling, meaning it was getting closer to the wall as well. And the wiring wasnt bad, it was an ultra simple circut (batterys in series, to crappy 3V motor and back to batterys)

I'll ask my dad later (he's an electrician)
I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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