Haven't Used my M4 in a year - No longer fires?

[RabidNinja64]

Just some quick clarification;

• My Rifle is the PJ4 CASV
  
• The gun was working prior to being put in storage.
  
• Battery was fully discharged then charged (1.0 Amp 2C LiPo)
  
• Initial "test", the motor had a very faint whirring prior to troubleshooting - Problem found?
  
• Tested voltage & continuity; Came back at 8.34 volts, with continuity dropping from a 1.34 to a .8 instantly (For you sparkies in here)
  

My brother is suggesting that it's something to do with the selector plate, as when I purchased the weapon, it had an issue with constantly firing when on auto, when the trigger was pulled, did unlock it, however and had no problems since, until now. Regardless, I'm a bit of a noob at the technical stuff for AEG's.

 

[Katana]

1amp 2c lipo? You mean 20C right? Maybe I'm missing something here but that battery could light maybe a small bulb but not an airsoft gun..

If you fully discharged your lipo and charged it again, it is probably dead and could of been very dangerous but it's still a 8 volts? You did say you charged it up again so that is probably why

Try a new battery would be the first thing...a whirring could be that it is trying to turn over but can't although in my experience it usually just makes this clunk or click/ no sound

Not sure about the constantly firing on auto but that sounds like the trigger shuttle is sticky? Deffo try a new battery to get that bitch pumpin' and jumpin'

Also, 1000mah is kinda shite and I would recommend something with at least 1300 as the motor needs some petrol to start.

 

[Samurai]

I think he meant 2 cells.

My first guess would also be the battery. If it was laying around for a year, it might have been damaged.

I don't understand the term continuity relating the battery, but I'm not a sparkie.

 

[RabidNinja64]

1amp 2c lipo? You mean 20C right? Maybe I'm missing something here but that battery could light maybe a small bulb but not an airsoft gun..

If you fully discharged your lipo and charged it again, it is probably dead and could of been very dangerous but it's still a 8 volts? You did say you charged it up again so that is probably why

Try a new battery would be the first thing...a whirring could be that it is trying to turn over but can't although in my experience it usually just makes this clunk or click/ no sound

Not sure about the constantly firing on auto but that sounds like the trigger shuttle is sticky? Deffo try a new battery to get that bitch pumpin' and jumpin'

Also, 1000mah is kinda shite and I would recommend something with at least 1300 as the motor needs some petrol to start.

Apologies, I do mean 20C  Damn typos! Referred to the site I bought it from (For technical info). http://www.taiwangun.com/en/electric/pj4-casv-black-p-j

I believe we went with the battery based on the fact my brother had a slightly more powerful one, and have a spare 11.1 that I daren't use for the sake of my internals. It's a G&P 1000mAH, so a generic and cheap one, but has worked with this gun on many other games previously. 

Regardless of the charge, I've tested the other batteries with my gun and my backup, and the backup works fine no problem, the gun is practically dead. not firing, as if there's no battery inside, even when connected.

 

I think he meant 2 cells.

My first guess would also be the battery. If it was laying around for a year, it might have been damaged.

I don't understand the term continuity relating the battery, but I'm not a sparkie.

" In electronics, a continuity test is the checking of an electric circuit to see if current flows (that it is in fact a complete circuit)." - Used a Voltmeter for this, got my readings and ensured that the battery was giving out 8 volts. Battery was tested in another gun, works fine.

A slight issue did occur, however, as my second continuity test (on auto), I slipped and shorted the battery while still connected, making a slight spark. I don't run anything like a MOSFET, the gun is as stock the day she was purchased, but if the motor isn't dead, im almost certain it is now.

 

[RabidNinja64]

No worries guys, just found the issue; My solder connections on the rifles connector are VERY VERY finnicky and were'nt connected properly. They've got heatshrink on them, so the damage isn't visible, but the cause is that my wires are a little too long, and seeing as it's rear-wired and I have short arms, I tend to keep my stock adjusted one notch out, so the connector cables are bended inwards, battery or not. Will get round to fixing it ASAP, but AshOnSnow, you are my savior.

 

[Lozart]

"In electronics, a continuity test is the checking of an electric circuit to see if current flows (that it is in fact a complete circuit)." - Used a Voltmeter for this, got my readings and ensured that the battery was giving out 8 volts. Battery was tested in another gun, works fine.

If you're going to throw quotes around at least make sure they're correct.

Continuity is a measure of electrical resistance, using a voltmeter will not show you this. A continuity test transmits a small electrical current through a circuit to ensure "continuity" ie a continuous circuit has been established. A continuity test of a battery is not possible with a standard meter, however what you did was measure the output voltage of the battery under no load. A battery condition meter would be more useful as this will place the battery under load and measure the loaded output of the battery (often less). This is somewhat redundant having tested the battery in another gun though as it would definitely point towards the problem being in the original gun.

At this point a continuity test WOULD be useful - set your multimeter to continuity or use a dedicated continuity meter and put it across the terminals on the lead to which you would connect the battery (DO NOT CONNECT THE BATTERY WHILE YOU DO THIS) and pull the trigger. The only resistance you should see will be the resistance of the motor windings which should be low. If you have a break somewhere in the circuit then you will get a high resistance reading or "open circuit" indication depending on your meter.

 

[Katana]

Make sure to check your compression as AEG's that have been stored away for a long time usually suffer from crap air seal due to o-rings crapping out and the lube can dry up.

 

[RabidNinja64]

If you're going to throw quotes around at least make sure they're correct.

Continuity is a measure of electrical resistance, using a voltmeter will not show you this. A continuity test transmits a small electrical current through a circuit to ensure "continuity" ie a continuous circuit has been established. A continuity test of a battery is not possible with a standard meter, however what you did was measure the output voltage of the battery under no load. A battery condition meter would be more useful as this will place the battery under load and measure the loaded output of the battery (often less). This is somewhat redundant having tested the battery in another gun though as it would definitely point towards the problem being in the original gun.

At this point a continuity test WOULD be useful - set your multimeter to continuity or use a dedicated continuity meter and put it across the terminals on the lead to which you would connect the battery (DO NOT CONNECT THE BATTERY WHILE YOU DO THIS) and pull the trigger. The only resistance you should see will be the resistance of the motor windings which should be low. If you have a break somewhere in the circuit then you will get a high resistance reading or "open circuit" indication depending on your meter.

Ugh im so sh*tty with words today  :blink:

Firstly, thank you for the in-depth and CORRECT definition of Continuity; last time I listen to my brother and his "electrical knowledge" and c+p wiki quotes in a rush.

I should've mentioned that I first checked the continuity of the gun, just as you explained, and did get low resistance readings. THEN I checked voltage of the battery and got back the standard 7.4 volts (Though it was somewhere around 8. something IIRC), but, again, in my hazy rush for tech support, I got the 2 muddled up.